T h e co n trib u tio n of A p titu d e Testing to th e V ocational R eh ab ilitatio n of A dults w ith T ra u m a tic B ra in In ju rie s
n ' • . •
i , , i i r . . , by
Jocelyne Lacroix
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B.A., Universile du Quebec a Trois-Riviercsk* ~ «<. ,™ ^ ^ ^ University du Qudbec & Trois-Rivieres
A Dissertation Submitted in Partial Fulfillment o f the Requirements for the Degree of DOCTOR O F PHILOSOPHY
in the Departm ent o f Psychology We accept this dissertation as conforming
to the required standard
D r R Spellacyi Supervisor (Department o f Psychology)
Dr, L, Costa, Departmental M ember (D epartm ent o f Psychology)
Dr. M . Masson, Departmental M ember (D epartm ent o f Psychology)
—
--r. j, Anderson, Outside M ember (D epartm ent olE ducation)
■; N *-■ \ ' — ^ — — —
-D r J.W. Mac-Donald, External Exam iner (-D irector o f Psychological Services, O.F, Strong Centre)
© JO C El Y N E LACROIX, 1992 University of Victoria
Alt rights reserved. D issertation may not be reproduced in w h ole or in part, by p h otocop yin g or other m eans, w ithout the perm ission o f the author,
Q
SERVICES 1625 North 1000 East I.ogan, Utah 84321, Phone: (801) 752-5698 Fax: (801) 752-5712 A ugust 25, 1992 Jocelyn# Lacroix D ear Jocelyne;T hank you fo r your kind letter o f A ugust 19, 1992.
PAQ Services grants you permission to include th e P A Q jo b dim ensions and aptitude attributes in; an appendix in y ou r dissertation.
W e wish you luck in the defense o f your dissertation. D r. M echam spoke highly o f the scholarly w o rk that you had done. He was im pressed w ith your careful research and concise reporting.
Please let us know if w e can be o f further assistance. Sincerely,
C onnie M echam PA Q Services C R M /
Societe
Canadienne
C I D I H
S ociete canadienne de !a Classification internationals d es d6ficioncos, d e s incapacites et d es handicaps. 1 Le 2 septemL re 1992 C.P. 225 Lao S a ln t-C h a rte s Q uribcc C a n a d a GOA 2H0 (418) 520-9141 pQSto 202
Madame Jocelyne Lacroix
OBJET: Autorisation de reproduction.
Chdre madame,
Tel que demandd, ll me fa it plaisir de vous autoriser & reproduire le matdriel relid d la proposition d'un nouveau moddle conceptual et de nomenclatures produites dans le cadre des travaux de recherche que j'a i dirij’ds pour la Socidtd Canadienne de la C1DJH et qul ont dtd publlds dans la revue "ftdse.au Internatio nal CIDIH" et cela, dans le cadre de votre thdse de doctorat.
En vous remerciant de votre inter&t pour nos travaux, veuillez, madame Lacroix, recevoir tous nos voeux de succds dans votre ddmarche doctorate,
Patrick Fouyeyrollas President
lie p i
A B S T R A C T
Neuropsychologisls are asked to provide information regarding a person’s ability to work following a traumatic brain injury (TBI), The tests used by Neuropsychologists were not constructed to identify specific abilities required for successful jo b performance. The lack o f criterion-related validity information makes it difficult to relate data obtained from neurospychological tests to specific occupations (Clemmons, 1985; Heaton & Chelune, 1978; Prigatano et at, 1986). This presents serious limitations for vocational assessment and rehabilitation of persons with traumatic brain injuries,
The General Aptitude Test Battery (GATB) is the vocational aptitude battery most widely used in vocational assessment, The GATB’s relationship to work demands makes it the most practical assessment tool available for job screening and matching, interpretive data for the GATB with persons with brain damage are scant (Clemmons, 1985; Cole, 1984), The person’s ability to w ork following a traumatic brain injury results from the interaction between their abilities/disabilities and demands o f occupations. Research in neuropsycho logy related to the vocational abilities o f brain-injured individuals has centred on measu ring the person’s incapacity,
This research investigates the GATB as an aptitude test battery for use w ith individuals with brain injuries and its usefulness for jo b matching with this population. The relation ship between the person’s measured aptitudes (GATB) and aptitude demands o f occupa tions (PAQ) is examined. This is refeired to as the person-job fit measure.
The GATB was administered to sixty (60) individuals with TBI. The Position Analysis Questionnaire (PAQ) was used to analyze participants’ occupations. It provides an estimate of the GATB aptitude scores o f incumbents successfully perform ing the position analyzed, that is, the aptitude demands o f the job,
Two categories o f occupations were analyzed;
"Can do"'. Occupations participants have the ability to perform, including positions currently held and jobs they have held since being injured and are no longer performing lor reasons unrelated to the brain injury; and
"Cannot do": occupations participants are unable to return to, or w ere unable to maintain for reasons related to the brain injury,
O ccupations were considered only if the person's ability or inability to do the jo b could be verified with the employer, co-worker(s), or (he professionals who assessed her (his) vocational potential.
T he structure o f the GATE) was investigated first with a large sample of regular jo b applicants and the confirmed structure was verified with the study sample. The GATB perform ance o f this group o f persons with TBI was examined, Lastly, the ability of the m easure of person-job fit to correctly classify participants by jo b category was analyzed. The results confirmed that the eight GATB aptitudes can be regrouped into three compos ites. Although this is useful for som e applications, for clinical intervention in a vocational rehabilitation process, the use o f all eight GATB aptitudes is recommended.
T he GATE' scores o f participants in this study tended to be lower than the Genera! W orking Population on many o f the GATB aptitudes, This reinforces the need for voea* tional rehabilitation intervention to help brain-injured persons enter o r reenter the work force.
Results indicated that the measure o f person-job fit using the GATB in conjunction with the PAQ provided a good indicator o f that person’s ability or inability to do a specific job, T h e person-job fit measures obtained from die GATB cognitive and perceptual aptitude com posites are the best predictors o f ability to work with this sample. The usefulness o f the GATB m otor aptitude and com posite is questionable,
E x am in ers:
T 7~l— --- -r~ * v ’
j
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Dr, F. Spellacy, Supervisor (Department of Psychology)Dr. L. Costa, Departmental M ember (Department o f Psychology)
. '■■■ J
Dr, M« M asson, Departmental Member (Department of Psychology)
Dr, J. A nderson, Outside M ember (Department o f Education)
J.W. MuM acDonald, External Examiner (Director o f Psychological Services, G.F. Strong Centre)
V
T a b l e o f C o n t e n t s i
A bstract , , ... , . , , , ...» , ... . . . it Table o f Contents ... , ... . . . V
List o f Tables ... ... ... xii
List o f Figures ... ... ... ... . . . xii.i A cknow ledgem ents... ... ... ... xiv
:i Dedication ..., ..., , ... ... XV C hapter One IN T R O D U C T IO N ... ... 1
' Chapter two LITERATURE R E V IE W ... . . . 5
f. VOCATIONAL IMPLICATION O F BRAIN I N J U R Y ... . . . 5
A. Return-to-W ork P ro b le m s ... ... 5
I . H igh Unemployment Rate ... . . . 6
2, Work Definition . . ..., ... ... 6
3., Factors Affecting Em ployability... . . . 8
(a) Severity of injury... , , . , . ..., ... ... 8
i (b) Pre-injury employment status... ... 9
(c) Follow-up period. , ... ... ... 10
(d) Demographic factors. ... . 10
4. Transfer o f S k ills ., ... . . ... , ... ... II 5. Vocational Goal Selection... ... ... II S u m m a ry: Return-to-W ork Problems , ... ... ... 11
B. N europsychological A ssessm ent o f Work A b ility ... ... ... 12
1. N europsychological Tests and Vocational O utcom e... . . . 13
(a) Individuals with epilepsy... . ______ 14 (b) Mixed etiologies... . . . 15
-(e) Participants in rehabilitation programs. ... .. ... .... 17
2. Clinical Judgm ent o f Work A b ility ... ... 18
S u m m a ry: Neuropsychological A ssessm ent o f Work A b ility ... . . . 18
C, Vocational A ssessm ent o f Work A bility. ... .. 19
1. Job M a tc h in g ... ... ... 19
2. The G A T B . . . ... ... 20
Conclusion . . . — ... ______ 21 II. THE GATB... ... ... ... .. ... 21
A, H istory/Basic D escrip tio n ... ... .. . . 21 B, N orm s... ... ... .. ____ _ 22
1, United States, 2. Canada
22
2222
23 23 23 24 25 C. Test B i a s . . , . ... 1. Sex ... ... ... 2. Geographical A r e a . ... . . ... 3. A g e ... ... 4. Ethnic M inorities , ... ... ... 5. E d u c a tio n ... >...Sum m ary: GATB N orm s/Biases... .. 25
D, Factor Structure o f the G A T B ... 26
1, Initial Factor A nalysis... - 26
2. Subsequent Factor A n aly ses... . . 26
Sum m ary: GATB Factor A n a ly s is ... 28
E. Psvqhometrie Properties... 29
1. V alidity ...— 29
(a) Content. . v . ... 29
(b) Predictive validity/criterion-related validity... 29
Sum m ary: V alid ity — 32
2. Reliability ... 32
(a) Over time ... *... 32
(b) Between forms... 33
Sum m ary: Psychometric P ro p e rtie s ... 33
F, T he GATB and the Disabled P o p u la tio n ... 33
1. Standardized Tests and Disabled Individuals... 33
2. The GATB and Disabled Individuals ... 34
3. Neurological Im p a irm e n t... 34
(u) Epilepsy. . ... 34
(b) Psychiatric impairment... 37
(e) Mixed etiologies... 38
Sum m ary: The GATB with N eurologically Impaired In dividu als... 38 G. T he GATB’s Relationship to N europsychological Test Batteries
Summary: The GATB and Neuropsychological Te s t s . . . . H. Critiques o f the G A T B ... C o n c lu sio n ... III. THE POSITION ANALYSIS Q UESTION N AIRE (P A Q )..
A. Introduction: Job M a tc h in g ... ... B. Definition/Description ... ... C. History o f the PAQ ...
39 41 41 43 43 43 44 44
D. Reliability... . ... ... Sum m ary, Inter-rater R eliab ility . ... ... E. Job Dimensions ... ...
1. Job Dimensions Based on Attribute Profiles
2, Job Dimensions Based on Job D a ta ... S u m m a ry ; Job D im ensions ... F. Job Component Validity o f the PAQ... S u m m a ry : PAQ Job C om ponent Validity w ith G A TB... C o n c lu s io n ... ... ... IV. HYPOTHESES AND Q U ESTIO N S... . , ... A. Structure o f the G A T B ... ...
H ypotheses ... . ...
B. GATB Performance o f Traumaticraly Brain-Injured Inuivtdu Hypotheses , ... ... C. Person-Job F i t ... ...
H ypotheses... ... Q u estio n s... ... C hapter Three M ETH O D AND PR O C ED U R E S... ...
I. PA R TIC IPA N TS... ... ... A. Selection C riteria ... ... ... 1. Presence of a Traum atic Brain Injury... 2. Age Range o f 18 to 54 at Time o f GATB Testing
3. Absence o f O ther Disorders ... . ... . . . . . 4. A Minimum of O ne Year P o st-In ju ry ...
5. L'm ited D isability... ... .. 6. Vocational H istory... ...
B. Recruitm ent P ro ced u re. ... C. University o f Victoria Human Subjects Procedure . . . . D. Recruitm ent and Selection o f Study S am ple ... .. E. Descriptive Statistics o f Study Sample ... , ...
1. A g e ... . ... ... 2. S e x ... . . ... ... ... 3. E d u c a tio n ... ... ... 4. Work S tatus — , 5. Description o f Occupation ... ... .. vii 45 45 45 46 47 48 48 51 52 52 53 53 54 54 54 55 55 56 56 56 56 56 57 57 57 57 57 58 58 59 59 61 61 63 65
Sum m ary : Descriptive Statistics o f Study Sample II. INSTRUMENTS U S E D ... A. G A T B ... B. P A Q ... Hi. PROCEDURE... A. Interview ... B. Release o f In fo rm atio n .. . . C. M e a s u r e s ...
I V, SUMMARY O F DEPENDENT AND INDEPENDEN A. Independent Variables ...
I . Dem ographic... ...
2, V oeationa! ... ... 3. M ed ica l ... ... 4, P sy ch om etric, ... 5. Aptitude Dem ands of Occupations B, Criteria or D ependent V ariables... V. CLINICAL ANALYSIS ... .. Chapter Four DATA A N A L Y S IS ...
I. GATB STRU CTU RE . . . . ...
A, Hypothesis Tested ... 1. Hypothesis A I, ... ... ... 2. The Statistical A nalysis Procedure Used. 3. Results ... ... B, Hypothesis T e s t e d ...
1. Hypothesis A2. ... 2. THe Statistical Analysis Procedure Used 3. R e s u lts . ...
TV A R AB LES
Sum m ary
...
II. GATB PERFO RM A N CE O F BRAIN-INJURED INDIVIDUALS A. Hypothesis T ested ...
1. Hypothesis B l. ... 2. The Statistical Analysis Procedure Used, 3. Results... ... B, Hypothesis T ested . ...
2, The Statistical Analysis Procedure U sed . . . ... . . . 3. Results ... ... S u m m a ry .
... ... , , , , ...
.
III. PERSON-JOB F I T ... ... ... .. A. Hypotheses T ested ,. ... ... ... ... 1. Hypothesis C l ... .. 2. The Statistical Analysis Procedure U se d . ... . . . . . 3. R e s u lts ... ... ... ... ... B. H ypotheses T e ste d .. ... ... ...1, Hypothesis C2. ... . . . ... ... 2, The Statistical Analysis Procedure U sed ... .. 3, R e s u lts . ... ... ... ... C. Question Investigated ... ...
1. Question C l ... ... 2. The Statistical Analysis Procedure Used... 3. Results... D. Q uestion Investigated... 1, Question C 2 . ... . . . . 2, The Statistical Analysis Procedure Used ... 3, R esults ... ... ... ...
Sum m ary
. ... ... ... ...
I V. ADD ITIO NA L STATISTICAL ANALYSES ... , , ... . . . . . A, GATB Scores of the Study Sam ple and Age. ... . , ... 1. Statistical Analysis Procedure Used. ... ... 2. R esults ... ... ... B, GATB Scores o f the Study Sample and Education at Intake,
1. Statistical Analysis Procedure Used ... ... 2. R e s u lts. ... ... ... C, GATB Scores o f the Study Sample and Em ploym ent Status at Intake. . . 1. Statistical Analysis Procedure Used... 3. R e s u lts , ... ... ... ...
Summary.
... ...
V. CLINICAL A N A L Y S IS ... ... A, International Classification of Impairments, Disabilities and Handicaps
(IC ID H V ... *
B, Climcal Analysis! Case o f A.F, ... 1. Participant's inform ation... ... ...
2. Vocational Profile ... 104
3. Risk Factors: C auses ... ... ... . ... 105
4. Organic Systems: Im pairm ents... 106
5. Abilities: D isabilities, ... . ..., . 107
Sum m ary: Abilities/Disabilities ... I l l 6. Environmental Factors: O bstacles/Facilitators... 11.2 7. Life Habits: Situation of H andicap... . , 113
(a) Situation of handicap at work: work aptitude... 114
S u m m a ry: Situation of handicap a t work: work a p titu d e ... 1.17 (b) Abilities/disabilities and aptitude attributes of the occupation, 118 S u m m a ry: Abilities/disabilities and aptitude attributes of the occupation 122 C. C on clusion ... 122
Chapter Five D ISC U SSIO N ... , ... 124
L GATB S T R U C T U R E ... 124
II. THE GATB W ITH BRAIN-INJURED IN D IV ID U A L S ... 126
A. Performance o f brain-injured individuals ... 126
B. Suggestions for clinical use o f the GATB with brain-injured individuals. 127 1, Speededness ... 128
2, Answer S h e e t ... 129
3, Subtest # 3* Spatial Perception Aptitude, G A T B -S — . 129 4, Subtest #7, Form Perception Aptitude, G A T B -P ... 129
5, M otor Aptitudes, GATB-F and M ... 129
6, Com puterizing th e G A T B ... 130
III. M EASURE OF PERSON-JOB F I T ... 130
A. The concept o f "situation o f handicap" (IC ID H )... 129
B. The measure o f person-job fit w ith the study s a m p le ... 132
C. Clinical use o f the m easure o f person-job fit... 133
IV. C O N C L U SIO N ... 134
V. LIMITATIONS O F TH E PRESEN T STUDY AND FUTURE R E S E A R C H .. 136
xi
Appendix A The General Aptitude Test Battery (G A T B )... .. 150
A ppendix B Position Analysis Questionnaire (P A Q )... 153
A ppendix C Information M ailed out to Potential P articipants ... 164
Appendix D Consent Forms ... ...„ . , ... 166
A ppendix E Inter-Rater Reliability PAQ ... 168
Appendix F Data Collection Questionnaire ... ... „, | 7 1 A ppendix G Template O f Letter Sent With Release O f Information . . 176
A ppendix H Internationa! Classification o f Impairments Disabilities and Handicaps ... ... 178
Appendix I Non Parametric Test o f Significance Using a Randomization Procedure... 200
List of Tables
Table 1 Multiple correlations o f PAQ Overall Job Dimension Scores
with GATB Test C riteria... 50
Table 2 Recruitment and Selection per Referral Source ... 58
Table 3 Inler-Rater Reliability; PAQ Data Processing... 69
Table 4 Inter-rater reliability: Intraclass c o rre la tio n , ... 70
Table 5 M ean GATB Scores o f Study S a m p le ... 81
Table 6 M ean GATB M otor and Non-m otor Com posite Scores o f Study Sample ... 84
Table 7 Person-job Fit per Job Category for each GATB A ptitude... 87
Table 8 Mean Person-job Fit per Job Category for each GATB C om posite. . . 89
Table 9 Classification per Category o f Occupation D iscrim inant Function A n aly sis... 92
Table 10 Correlations Between GATB Composites and Job T y p e ... 92
Table 11 Multiple Regression o f Job Type onto Measure o f Person-job F it (Com posite)... 93
Table 12 Correlation: GATB A ptitude and A ge... 95
Table 13 Correlation: GATB A ptitude and Secondary Education at Intake . . . . 96
Table 14 A nova: GATB Aptitude and Post-Secondary Education at In ta k e . . . . 97
Table 15 M ean G ATB Scores of Unemployed (G l) and Em ployed (G2) Participants at Intake... 99
Table 16 Situation o f Handicap at Work: Work Aptitude and Aptitude Demand o f Occupation Rental Truck Service W orker ... 116
Table 17 Inter-Rater Reliability (PAQ e n te r-A c t) ... 168
List of Figures
Figure 1, Age at In ju ry ...*... , ... ... 59
F igure 2, Age at In ta k e ,..., ... ... 60
Figure 3, Sex R atio... ... 61
Figure 4, Education at In ta k e ..., . , , . 62
Figure 5, Post-Secondary Education at Intake... 62
F igure 6. Em ploym ent Status at I n ta k e ... ... 63
F igure 7, Attempt to Work Post-Injury vs Work Status at Intake ... 64
F igure 8, Confirmatory Factor A nalysis with OATB Data o f Regular Job A p plicants... . . , , , ... 77
Figure 9. Confirmatory Factor Analysis with Study S a m p le ,... 79
Figure 10, Confidence Intervals: Mean GATB Scores, Study Sample ... 82
A C K N O W L E D G E M E N T S
This research was supported in part by the Innovations Program o f Em ployment and Immigration Canada,
The endorsem ent of the p eject by Frank Spellacy and Associates, G,F. Strong Rehabilita tion Centre, the Vocational Consulting Group, Headwork, and the Victoria Vocational College is gratefully acknowledged, as is the collaboration o f individuals who have sustained traumatic brain injuries,
The author is thankful to members o f her doctoral com m ittee chaired by Dr, F. Spellacy for their review and suggestions, The author thanks Dr, M ichael A, Hunter for his professional advice with research design and data analysis, The author wants to acknowledge the work of Mr, David Almida and Ms. Francine Giroux, in com puter data m anagement and statistical analysis and Mr. Richard Chadwick, for developing the com puter program necessary for some of the analysis.
D E D IC A T IO N
To Ted w ho’s unbound enthusiasm for life inspired me to take on this challenge.
I
n t r o d u c t io nThis chapter presents the purpose o f the study and an overview o f the research, describing the methodology and scope o f the study. The organization and layout o f the dissertation are outlined.
Epidemiologic investigations conducted in the United States during the past ten years have reported between 422,000 and 500,000 head injuries per year (Anderson & M cLaurin, 1980; Rapp & Spivack, 1986; Rosenthal, Griffith, Bond, & Miller, 1990), Although the 1986 census in Canada inquired about disabilities, head or brain injury was not included as a separate category. Extrapolating from the American data, however, an incidence o f more than 50,000 victims per year is estimated.
%
All surveys (National Head and Spinal Cord Injury, 1980; National Head injury Founda tion, 1986; U.S. Department of Education, 1981 in above epidemiologic studies) identified people under 30 years o f age as the most vulnerable, accounting for approxim ately 70% o f closed head injury (CHI) victims. Because a large num ber o f victims are o f w orking age, researchers have given special attention to the vocational outcome o f individuals with brain injuries.
Reintegration into the labor force is the ultimate goal o f many individuals and rehabilita tion programs, Return to work is often used as a measure of overall recovery from injury and o f the success o f rehabilitation programs,
A key factor in the vocational rehabilitation process leading to jo b placem ent and main tenance is the. initial jo b matching. Job matching is the process o f fitting a person’s abilities and disabilities with the demands and characteristics o f occupations,
The primary aim o f this study was to investigate the utility o f the G eneral Aptitude Test Battery (GATB, United States Department o f Labor, 1970) for job matching with in dividuals who have sustained traumatic brain injuries.
2
The GATB w as used in combination with the Position Analysis Questionnaire 'PAQ), a measure of the aptitude demands of occupations, to produce a measure o f person job fit. Person-job fit is a m easure o f the com petence (or inadequacy), related to work aptitudes, that an individual has o r may experience in a specific occupation, The study also provides further information on the GATB performance o f individuals with brain injuries,
The dissertation is organized into five chapters and a series o f appendices. Chapter Two presents the m ajor findings o f a review o f literature pertinent to the study. The perceptual, cognitive, and behavioral dysfunctions consequent to brain injuries have serious educa tional, vocational, and social implications. The first part o f Chapter Two details the problems that brain-injured individuals experience obtaining and maintaining em ploy ment, and the factors that determine an individual’s employment potential following a traum atic brain injury. Work ability is typically assessed with psychological and neuro psychological tests. These tests are sensitive to brain dysfunctions, but, as the literature review reveals, lim ited in their ability to actually predict vocational outcome. The General Aptitude Test Battery (GATB), the most com monly used tool ip vocational counselling and rehabilitation, m easures the same w ork-related aptitudes by w hich the Canadian Classification and D ictionary o f Occupations (C-CDO) breaks down occupations into job demands. The second part o f Chapter Two focuses on the GATB, describing its history, characteristics, validity as a predictor o f w ork performance, relationship to neuro psychological tests, and strengths and it’s weaknesses as a vocational assessm ent tool for specialists w orking with the disabled population,
In order to study the GATB’s usefulness for jo b matching with brain-injured individuals, the relationship between their measured aptitudes and the aptitude demands o f specific occupations had to be exam ined, Thus, the third part o f the chapter focuses on the Position Analysis Q uestionnaire (PAQ), a tool that measures the aptitude demands o f various jobs. The PAQ deals with jo b characteristics as they imply human characteristics or behaviors that can be quantified and analyzed, Literature on the PAQ’s history, reliability, validity, and uses is presented, The factors that guided selecting it as a job analysis procedure arc summarized. The chapter concludes with a presentation o f the hypotheses and questions raised by the literature review.
C hapter Three presents the methods and procedures used to investigate the hypotheses and que^Mons posed, Sixty people between the ages o f 18 and 54 participated in the study, recruited from a rehabilitation centre, three private clinics, and a vocational college. The procedure for requesting participation and the criteria for selecting participants are described. A description o f the study sample and descriptive statistics o f the demographic variables (age, sex, education, employment) are offered, A presentation o f th#* instruments used — the GATB and the PAQ — and the procedure used to gather data follows. The occupations that were analyzed were divided into tw o categories: jo b s participants cou I do, and job s they could not do, The chap'or concludes with a summary of the dependent and independent variables.
Chapter Four presents the statistical analysis procedure used to test every hypothesis and exam ine each question. The results of the data analyses follow, starting with the structure o f the GATB. The results o f GATB factor analysis are presented, followed by the applica tion o f the confirmed model to the sample o f traum atically brain-injured people. In the next section, the GATB scores o f the participants are exam ined in relation to the hypotheses slated. The scores are compared with those o f the General Working Population, and the relationship between mean GATB scores and participants’ age, education, and em ployment status are analyzed.
Finally, the central question of the study is addressed. The measure o f person-job fit is presented, and the extent o f the fit is analyzed for all GATB aptitudes and com posites and jo bs participants could and could not do. The utility o f the person-job fit rtieasure for judging a traum atically brain-injured person’s ability to w ork is examined, The last part of Chapter Four consists o f a clinical case analysis that presents a detailed exam ination o f the interaction betw een one o f the participant's abilities and disabilities consequent to traum atic brain injury and the demands o f his occupation.
In Chapter Five, the results presented in the previous chapter are discussed, The implica tions of the findings, for research and clinical intervention purposes, are presented, starting with those related to the structure of the GATB. Following is a discussion o f the use o f the GATB with individuals with traum atic biain injuries. Suggestions for alternative adm inistrations o f the GATB and possible modifications to the battery that may facilitate its use with traum atically brain-injured individuals are presented. The significance o f the measure o f person-job fit is discussed last. The conceptual fram ew ork o f the measure, the
4
m easure’s usefulness for jo b matching, and its applications in the vocational rehabilitadon process are addressed,
Finally, the conclusions and the limitations o f the study are presented, ending with suggestions for future research.
L
it e r a t u r eR
e v ie wThis chapter consists o f four parts. The first deals with the vocational im plication o f brain injury, focusing specifically on the problems that people with brain injuries experience obtaining and maintaining employment. A brain-injured person’s ability to w ork is usually assessed by psychological and neuropsychological tests, which are sensitive to brain dysfunctions, but have limited validity as predictors of w orkability. The General Aptitude Test Battery (GATB), used in vocational counselling and rehabilitation, measures aptitudes related to work demands and may be useful to determ ine vocational options for brain-in jured individuals. Thus the second part o f the section concentrates on the GATB, present ing a review o f the GATB’s characteristics and of related literature. Vocational rehabilita tion involves assessing not only a person’s spared and impaired abilities, but also the demands o f occupations. The third part o f this chapter presents a review o f the Position Analysis Questionnaire (PAQ), the jo b analysis tool used to measure jo b dem ands, and related literature. The chapter concludes with a presentation of the hypotheses and ques tions raised by the literature surveyed.
I. VOCATIONAL IMPLICATION OF BRAIN INJURY
A. Return-to-Work Problems
Brain injuries affect a variety o f cognitive, behavioral, and physical abilities. Deficits in these areas, individually o : in combination, are barriers to obtaining and m aintaining em ploym ent. In the past decade, a great deal o f research has focused on the problems encountered in the vocational rehabilitation o f traumatically brain-injured persons (Ben- Yishay, Silver, Piasetsky, Sc Rattok, 1987; Fraser, 1988; Fraser, Dikrnen, et al, 1988; Heaton & Chelune, 1978; Prigatano et al. 1984,1986; Wehman, Kreutzer, Wood, M orton, & Sherron, 1988; Wehman, Kreutzer, Stonnington & Wood, 1988). A lthough a detailed examination o f the literature dealing with the vocational outcome o f brain injury is beyond the scope o f this study, a brief review o f the m ajor problems is presented.
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1.
H igh Unemployment RateSecuring and maintaining employment is the first challenge that brain-injured individuals face. Work status following a brain injury— that is, whether a person is employed or unem ployed— is a com m on m easure o f vocational-outcom e studies. The literature reviewed indicates that 12 to 82% of persons with a traumatic brain injury are un employed. P o st-1970 studies have revealed higher unemployment levels, reflecting, per haps, an increase in the number o f survivors o f severe injuries. The highest em ploym ent rate recorded was am ong bntin-injured people w ho had participated in a comprehensive rehabilitation program: Ben-Vishay et al. (1987) and Prigatano et al, (1984, 1986) reported that 42 to 60% o f participants returned to com petitive employment 1 to 3 years after being discharged from hospital,
The wide range in the overall unemployment rate reflects the multiple factors that in fluence an individual’s ability to obtain and maintain employment, and the fact that; researchers have controlled for different determ inants and defined factors such as severity o f injury and em ploym ent status differently.
2. Work Definition
T he term em ployed usually refers to paid, com petirive employment, M any researchers use the expressions com petitive employment and competitively em ployable, but competitive is rarely defined.
Competitive alludes to a work market in which employers arc concerned primarily with identifying and hiring applicants who will perform optimally, It is important to know the basic components o f a com petitive labour market in order to identify the areas o f skill that m ust be assessed. N eff (1968), Wehman (1981), and Rush (Ed.) (1986) suggested that w orking in a com petitive labour market encom passes: (a) possessing or having the ability to acquire the skills and interest required o f specific occupations or families o f occupa tions; (b) having the capacity to obtain em ploym ent by competing on the open labour market; and (c) being capable o f maintaining employment, All of these abilities can be impaired following a brain injury. In order to determ ine an individual’s ability to compete, the brain injury’s im pact on these abilities must be assessed, It is also necessary to define the terminology used as a m easure of vocational outcome and to specify the tools that
assess the elements of the co n cep t To conclude that brain-injured persons, individually or as a group, are competitively employable has serious implications in the areas o f com pen sation and availability o f vocational rehabilitation services. Psychologists must be cautious in their use of the terminology addressing work status.
The period o f tim e an individual must work in order to be classified as either em ployed or unemployed has varied among studies. Employed w as defined by Sayless, Varney and Roberts (1989) as having worked 75 percent o f the time during the last 2 years, by Dennerll, Rodin, Gonzales, Schwartz and Lin (1966) as having worked 10 out o f 12 months, and by Newman, Heaton and Lehman (1978) as having worked full-time for the last 6 months. These sam e researchers (listed in the sam e order) each defined unemployed as not having worked m ore than 25% o f the time during the last 2 years, having worked 3.8 out of the last 12 months, and not having worked during the last 6 months.
The employed group may o r may not have been differentiated on the basis o f part-tim e and full-time work. Part-time employment, also referred to as underemployment (Clemmons, 1985), was usually defined by the Humber of hours w orked in a week, or as a percentage o f time worked, ranging from 75% to 25%. Wehman, Kreutzer, West, et al. (1989) proposed a monthly em ploym ent ratio to measure em ployment: the num ber o f months a person worked during a determined phase over the total number o f months he or she could have worked. The post-injury phase started on the date o f hospital discharge. W ehm an’s measure of vocational outcome appears less arbitrary ai?d thus m ore useful.
General categories of work, such as skilled versus unskilled and competitive versus sheltered/subsidized, w ere operationalized (Ben-Yishay et al. 1987; Bowman, 1991; Najcnson, Groswasser, M endelson & Hackett, 1980). Fraser, Dikmen, et al. (1988) used the Dictionary o f Occupational Titles (DOT) to classify occupations and their levels of complexity. Descriptive measures of em ployment have included the Hollingshead occupa tional rating (Dikmen & M organ, 1980) and the level attained in a sheltered workshop (Malgady, Barcher, Davis and Towner, 1980). Q ualitative measures, such as work perfor mance, were determined by supervisors* ratings (Clemmons, 1985).
The aptitude demands o f Various jobs were measured in two studies. Clemmons (1985) used the Occupational A ptitude Pattern (OAP), which determines the m inimum aptitude requirements o f an occupation as listed in the D ictionary o f O ccupational Titles (DOT).
Newman et al, (1978) used a research tool called the Minnesota Job Requirements Q uestionnaire (MJRQ), which estim ates aptitude demands based on clients* ratings o f the jobs. The M JRQ has not been subsequently developed as a commercially available
measure,
3. Factors Affecting Employability
Subgroups w ithin the population o f brain-injured people have experienced varying degrees of difficulty finding and m aintaining em ploym ent, depending on such factors as severity o f injury, pre-injury employment status, post-injury <me lapse, and sex, age, and education,
(a) Severity o f injury.
T he severity o f a brain injury has been variously defined. Comm on measures used are the Glasgow C om a Scale score, the duration o f post-traumatic amnesia, and the length o f hospitalization, A brain injury has been classified as severe if the post-traumatic amnesia lasted more than 24 hours (Oddy & Humphrey, 1980) or at least 2 clays (Brooks et al, 1987), and/or if the patient’s G lasgow Coma score at the tim e o f injury was 8 or less (Levin et al. 1979). Fraser, Dikmen, et al. (1988) classified injuries as mild (124-), moderate (9-11), or severe (3-8) according to Glasgow Com a scores. Rimel et al, (1981) defined a m ild head injury as one presenting the combination o f a minimum score o f 13 on the Glasgow Coma Scale, loss o f consciousness for up to 20 minutes, and up to 48 hours’ hospitalization.
Em ploym ent rates ranging from 29 to 84% were recorded am ong those with severe head injuries (29% , Brooks, McKinlay, Symington, Beattie & Cam psie, 1987; 44% , Levin, G rossman, Rose & Teasdale, 1979; 61% at 6 months, 82% at 1 year, and 84% at 2 years, O ddy & Humphrey, 1980). A m ong those with m ild head injuries, the rates ranged from 76 to 91% (76% , Rimel, Giordani, Barth, Bot; and Jane, 1981; 91% O ’Shaughnessy & Fowler, 1984), Fraser, Dikmen, et al. (1988) reported an overall return-m work rate o f 73% in a sample in which 60% o f the participants had sustained mild head injuries.
S om e authors have suggested a r orer vocational outcome, including inability to work at all, as the length o f coma increases (Dresser et al, 1973) and as the length o f
post-traumatic am nesia increases (Levin et al. 1979; Oddy & Humphrey, 1980). However, other researchers did n o t find a significant relationship between vocational outcom e and the severity o f injury as measured by the duration o f post-traumatic amnesia (Brooks et al. 1987; Johnson, 1987). This m ay be due in part to the lack o f common measures of post-traumatic amnesia.
Severity o f injury has also been measured by the deficits present following the injury. Dresser et al. (1973) found significantly greater chances o f unemployment among patients with aphasia, visual im pairm ent, combined m otor deficits, and seizures. Their study included penetrating head injuries, and a significant relationship between depth o f injury and unemployment was observed. Levin et al. (1979) found that post-injury oculoves- tibular deficits were associated with greater levels o f impairment, which in turn were related to poor vocational outcome.
On the whole, residual cognitive, emotional, and behavioral sequelae o f brain injuries greatly exceed physical deficits as a cause o f difficulty in long-term vocational rehabilita tion (Brooks et al, 1987; Bruckner & Randle, 1972; Clemmons, 1985; Lezak, 1987; Prigatano et al. 1986). An individual’s ability to return to work is affected by a variety of deficits: memory problems, personality change, loss o f em otional control, concentration problems, slowed mental processing, social isolation, aspontaneity, and a tendency to fatigue (Fahy, living & Millae, 1967; Long, Gouvier & Cole, 1984; Thomsen, 1984; Van Zomeren & Van Den Berg, 1985; Najenson, Groswasser, Mendelson & Hackett, 1980; Groswasser, M endelson, Stern, Schechter & Najenson, 1977). A num ber of studies indi cate that brain injuries producing greater memory, learning, and personality deficits result in poorer work adjustments than do injuries similar in severity, but producing fewer deficits in these spheres (Bond, 1975; Bruckner & Randle, 1972; Weddell, Oddy, & Jenkins, 1980). Although physical limitations appear less restrictive, Wehman, Kreutzer, Stonnington, et al. (1988) found that they were barriers to placement in supported employment programs when th e y were com bined with cognitive impairments.
(b) Pre-injury employment status.
Some studies compared pre- and post-injury em ploym ent rates. Levin et al. (1979) found that the em ployment rate dropped from 96% before injury to 44% after injury. Participants in their study had sustained severe head injuries, and their employment status was
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measured 6 months to 9,5 years after their injuries, Rimel et al. (1981), considering only those people who w ere em ploye* before they w ere injured, observed a post-injury em ploym ent rate of 66% , Brooks et a l (1987) measured participants’ em ploym ent status over a 7-year period, and noted that the em ploym ent rate dropped from 86% before injury to 29% after injury.
O f those w ho were employed prior to being injured and who successfully returned to w ork, many took on less dem anding positions (Brooks et al. 1987, Clemmons, 1985; Fraser, D ikm en, et al. 1988; M cM ordie, Barker, & Paolo 1990).
(c) Follow-up period.
Follow -up periods have varied enormously, from 3 months (Rimel et al, 1981) to between 7 and 9.5 years (Brooks et al, 1987; Levin et al, 1979), Brooks and colleagues found no evidence that em ploym ent likelihood increases more than 2 years post-injury, and a reexam ination o f Thomsen (1984) supports this conclusion. Ben-Yishay et al, (1987) noted a decline in em ploym ent rate in a post-discharge period o f I to 3 years,
(d) Demographic factors,
The relationship between dem ographic factors and return to work following a brain injury has not been consistently addressed, and studies have produced varied conclusions, Rao et al. (1990) noted that the brain-injured individuals who returned to work w ere younger, had shorter com a periods and stays in rehabilitation centres, and had higher institutional discharge scores. Brooks et al. (1987) and M cM ordie el al, ( 1990) suggested that chances o f em ploym ent decrease for brain-injured individuals aged 40 and older, Although Rimel et al, (1981) found a higher percentage o f em ploym ent with increasing age, their sample appears to have included children, and it did not sufficiently define increasing age.
T he sex variable has been difficult to study because most samples are predominantly male. Brooks et al. (1987) suggested a nonsignificant trend o f a higher return-to-work rate for females. M cM ordie et al, (1990) surveyed a group of brain-injured adults (n - 177) and reported that females were m ore likely than m ales to return to work, Rimel et al, (1981) found higher rates o f post-injury em ploym ent among individuals with higher education levels and socioeconom ic status. Wehman, Kreutzer, Stonnington, e t at. (1988) noted increased likelihood o f placement am ong those with higher educational levels. Brooks et
al. (1987) found that pre-injury occupational level did not significantly relate to return to w ork follow ing a head injury,
4. Transfer o f Skills
Difficulties transferring acquired skills have been observed am ong brain-injured in dividuals in vocational rehabilitation. Prigatano e t al, (1986), following the evaluation o f the O klahom a rehabilitation program, suggested that work trials be included in vocational rehabilitation, since patients are not able to transfer skills acquired through clinical rehabilitation to the work environment. The levels o f functioning patients dem onstrate in structured rehabilitation settings is not always exhibited ui the w orkplace (Weinberger, 1985). In response to this problem, the supported employment model (Fraser, 1988; Wehman, Kreutzer, Stonnington, et al. 1988; Wehman, Kreutzer, Wood, ct al. 1988; Kreutzer, Wehman, M orton,& Stonnington, 1988; Wehman, Kreutzer, West, et al. 1989; Wehman, Kreutzer, Wood et al, 1989; Wehman, West, et al. 1989) extends vocational rehabilitation intervention to the work site,
5. Vocational Goal Selection
O ne of the difficulties encountered <n the initial stage of community vocational rehabilita tion is setting realistic vocational goals. The organically based deficits associated with brain injuries— lack o f awareness and impaired judgement, for instance — and the denial o f deficits that is often observed after a traum a have frequently resulted in unrealistic vocational goals, w hich have in turn led to failure (Ben-Yishay, 1987; Prigatano et al. 1986; Wehman, Kreutzer, Stonnington, et al. 1988). The impact o f this problem is reflected in unem ploym ent rates that were higher 3 years post-injury than they were at 1 year post-injury (Ben-Yishay et al. 1987).
S u m m a ry:
Return-to-Work Problems
Research into return to work following a brain injury has exposed problem s in obtaining and maintaining employment. Researchers have examined the roles o f several moderating factors and used many definitions of work, A patient’s socioeconomic status, the injury itself, and post-injury rehabilitation are factors that determine his or her em ploym ent
potential. High rates o f unem ploym ent remain even alter rehabilitation intervention, Brain-injured individuals who return to work are likely to occupy lower-level positions, and many have trouble m aintaining employment.
The most common evaluation o f work success is w hether people are employed or un em ployed, and w hether those who are employed work full-time or part-time. Other measures, in order of the frequency with which they are used, are categorization o f position held, jo b perform ance as rated by employers, and jo b demands as rated by participants. Information about participants' work status has been obtained from patients in the majority o f studies, and from employers occasionally.
A marked lack o f consideration has been given to specific definitions of the variables used to measure vocational outcome, Definitive measures of the demands of occupations held or unsuccessfully maintained by brain-injured individuals are noticeably limited. The two studies that determined the aptitude demands o f the subjects’ occupations (Clemmons,
1985; Newman et al. 1978) used treasures that w ere later abandoned,
The prevalence o f problems that brain-injured individuals experience entering and re entering the work force calls for vocational rehabilitation intervention, The leading rehabilitation programs include vocational rehabilitation components within the treatment centre (Ben-Yishay et al. 1987; Prigatano et al, 1986) or in the community (Praser, 1988; Wehman, Kreutzer, Stonnington, et al. 1988).
W hether set in a holistic rehabilitation program or a com m unity vocational service, the vocational rehabilitation process begins by assessing individuals’ abilities. This leads to jo b matching and setting realistic vocational goals.
B. Neuropsychological Assessment of Work Ability
G iven the nature of the deficits caused by a traum atic brain injury, an individual’s ability to w ork is usually assessed by a Neuropsychologist. M any researchers have studied the relationship between neuropsychological tests and work ability, focusing on two areas: the tests’ ability to predict vocational outcome, and their usefulness in making a clinical judgem ent o f the person's capacity to work.
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Neuropsychological Tests a n d Vocational OutcomeThe majority o f researchers investigating the predictive and discriminative abilities o f neuropsychological tests have used expanded versions o f the Halstead-Reitan Battery (Bowman, 1991; Clemmons, Fraser, Dodrill, Trejo & Freelove, 1987; Clemmons, 1985; Dennerl! et al, 1966; Dikmen & Morgan, 1980; Heaton & Chelune, 1978; Newman et at. 1978; Schwartz, Dennerll, & Lin, 1968), The Minnesota M ultiphasic Personality Inven tory (MMPI) is most often included as a personality m easure (Bowman, 1991; Heaton & Chelune, 1978; Kunce & Worley, 1970; Newman et al. 1978; Wehman, Kreutzer, Ston nington, et al. 1988). Occasionally, studies have focused on the usefulness o f individual tests (Tinker Toy Test: Bayless et al. 1989; Wechsler A dult Intelligence Scale (WAIS): Shalock & Harper, 1980; Webster, 1974, 1979).
Research indicates that com posite scores are more powerful predictors than individual tests. The composite scores used were derived from established indexes, such as the Halstead-Reitan Impairment Index (Bowman, 1991; Dennerll et al. 1966, Newman et al. 1978; Fraser, Dikmen, et al. 1988) the WAIS Performance (PIQ), Verbal (VIQ), and Full Scale (FIQ) IQs (Clemmons, 1985; Heaton & Chelune, 1978, Newman et al. 1978), and the Wechsler Memory Quotient (Heaton & Chelune, 1978; Prigatano et al. 1986). Som e researchers (Acker in Uzzell & Gross (Eds.), 1986; Dikmen & M organ, 1980; Kunce & Worley, 1970) regrouped tests in factors, on the basis o f face validities or clinical ju d g ments, and obtained average factor scores. In the Santa Clara M edical Centre (CMC A cker in Uzzell & Gross (Eds.), 1986) Head Injury Project, test scores were transformed to a common measure (t or Z) and converted to an impairment index based on a Lickert scale. Some individual and subtest scores were also found to be significantly related to em ploy ment status, including Digit Sym bol in the WAIS (Prigatano et al. 1984; Stuss et al. 1985) Visual Reproduction and Paired A ssociates in the W echsler M emory Scale (W M S) (Prigatano et al. 1984), the Paced Auditory Serial Addition Task (PASAT) (Brooks et al. 1987; Oronwull, 1977), Finger Tapping (Dennerll, 1966), Stroop Color-Word Interference Test (Stroop) (Clemmons & Dodrill, 1983), Trail B (Dennerll et al. 1966; Heaton & Chelune, 1978), Category Test (Dennerll et al. 1966; Heaton & Chelune, 1978), and M M PI (Bowman, 1991; Heaton & Chelune, 1978).
It is not surprising that composite scores are more often found as predictors: Work is a com plex task requiring a com bination o f abilities, and a composite synthesizes a group o f skills, more accurately reflecting the global criterion measured as work/no work,
The following section presents a brief review of literature from different categories o f study, in order to illustrate the use o f neuropsychological tests in predicting ability to work, (a) Individuals with epilepsy.
Several researchers have exam ined the differences between the neuropsychological functioning o f employed and unemployed epileptic patients. Dennerll et al. (1966) found that unemployed epileptic patients sccicd significantly lower 011 the WAIS than employed patients did, and performed significantly poorer on I I of the 15 Halstead-Reitan tests. The personality and psychological adjustm ent measures used were the California Psychologi cal Inventory (CPI) and the Edwards Personal Preference Schedule (EPPS), These measures indicated that levels o f social com petence are related to increased chances o f em ploym ent. It is worth noting that the unemployed patients had significantly fewer years o f education, histories o f earlier onset and longer duration o f epilepsy, and poorer respon ses to medication than those in the employed group, Although they were considered only mildly impaired, the unemployed patients’ overall neuropsychological impairment was significantly greater than that o f the em ployed group,
Schwartz et al, (1968), using a battery of tests almost identical to that used by Dennerll, found that a particular combination o f neuropsychological and personality measures suc cessfully identified the em ploym ent status o f 77% o f the employed participants and 80% o f the unemployed, The best individual predictors o f current em ploym ent status were three WAIS subtests (Comprehension, Similarities, and Digit Symbol) and two CPI scales (Self-Acceptance and Social Presence, both o f which load on the social competence factor). Possible neurological differences between the groups were not reported,
Dikmen and Morgan (1980) grouped a series of 36 neuropsychological tests into six com posites (Verbal, Visual-Spatial, Flexibility in Thinking, Memory and Alertness, Motor, and Concept Formation) according to face validities, They investigated the ability o f individual and com posite tests to differentiate between employed and unemployed epilep tic persons, and high and low occupational status (Hollingshead occupational status
ratings), individual and com posite measures o f Flexibility in Thinking and M emory and Alertness consistently differentiated between employed and unemployed, and the com posites differentiated between high and low occupational status. The unem ployed low- status group performed the worst and the employed high-status group the best on neurop sychological tests. The unemployed group generally had fewer years of education, and low occupational status was associated with an earlier onset and longer duration o f seizures. Clemmons and Dodrill (1983) examined the em ploym ent status o f 42 young adults with epilepsy, 38 o f whom were high school students at the time o f testing. The average follow-up period was 6,44 years. The neuropsychological measures that were significant predictors o f em ploym ent status were WAIS IQ scores, the percentage o f neuropsychologi cal test scores outside the normal limits, and the MM PI. The average IQ o f the 56% who were unemployed was at the low end of the normal range, and significantly low er on all three IQ scores than that o f the employed. A higher percentage o f neuropsychological test scores outside the normal limit was observed am ong the unemployed, The M M PI was not found to be related to em ploym ent status at follow-up.
In summary, research suggests that unemployed persons with epilepsy are more likely to have histories o f earlier onset o f seizures, to have less education and attain lower occupa tional status, and, often, to have lower WAIS IQs. At least one study has related this population’s neuropsychological problems to difficulties with flexibility o f thinking, atten tion, and memory, Information on personality characteristics is sparse, but studies indicate that social com petence is more often found among the em ployed than the unemployed. Clemmons (1985) concluded that the leading cause o f unem ploym ent am ong people with epilepsy is not the presence o f seizures, but organically based intellectual and psychosocial deficits.
(b) Mixed etiologies.
Studies by researchers at the Colorado University Health Science Centre (Heaton & Chelune, 1978; Heaton & Pendleton, 1981; Newman, Heaton & Pendleton, 1978) are good exam ples o f research into the role o f neuropsychological tests in m easuring w ork ability, T he patients studied had sustained brain injuries o f various origins— trauma, Cerebral Vascular A ccident (CVA), tumors, anoxia, epilepsy, psychiatry, and surgery. U sing the Halstead-Reitan battery o f neuropsychological tests, expanded with the WAIS, M M PI,
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three subtests o f the Peabody Individual Achievement Test (PIAT), and WMS, Heaton & Chelune, (1978) investigated the predictive validity o f test performance for work s t a t u s - full-time, part-time, or unemployed—-in a sample o f 381 patients. They concluded that; neuropsychological tests and MMPI are useful in predicting work status. T h e full-time employed performed best, the unemployed poorest, and the part-time employed at an intermediate level. Participants in all three groups were within the normal range on the WAIS Full Scale IQ, a fact that supports Lezak’s (1987) conclusion that Full Scale IQ is not a useful m easure o f cognitive abilities following a traumatic brain injury, There were greater differences between the VIQ and PIQ scores o f unemployed participants; they scored lower than average on the PIQ. The employed participants scored within the normal range on the Halstead-Reitan Im pairm ent Index, and the unemployed obtained scores within the mild to moderately impaired range on most o f the Halstead-Reitan tests. M ore personality disturbances were observed in the unemployed group,
The researchers carried out multiple regression and discriminant function analysis with half o f the sample, allowing for cross-validation, O f the 10 best predictors o f unem ploy ment, the Halstead-Reitan Impairment Index was the single best predictor, T he stepwise discriminant function analysis used selected measures— Russell’s Average Impairment Rating (AIR), WAIS-VIQ and PIQ, PIAT, and/or the MMPI scales— to discriminate between full-tim e em ployed and unemployed. Using neuropsychological tests alone, the em ployment status o f 74.2% o f the participants was correctly identified. Using only the M M PI, alm ost 79% were correctly identified. These classification rates compare well with the 84% categorization rate obtained from the combination o f neuropsychological and personality testing, False negative and false positive were not calculated. Adding the education variable as a predictor lowered the classification rate, Based on these findings, the authors suggested that current adaptive ability as tapped by many o f the n euro psychological tests may predict likelihood o f em ploym ent, but is Jess helpful for identify ing accessible jobs,
Newman et al. (1978) followed up 78 persons who had been referred for neurop sychological testing. The interval between testing and follow-up was at feast 6 months for 81% o f the group. The participants who had been employed in the previous 6 months com pleted the M innesota Job Requirements Questionnaire (M JRQ), which rates jo b
requirements and estimates dem ands with respect to the nine ability factors of the General Aptitude Test Battery (GATB),
Newman and his colleagues used the neuropsychological tests as predictors o f future employment Status, income, and estimated cognitive and perceptual aptitude requirements, T he tests correlated not only with employment status, but with income and aptitude requirements, Using stepw ise multiple regression, the researchers found that the AIR index was the most sensitive predictor o f chronic unemployment. Using an AIR index cutoff point of 1.61, 78% o f the unemployed were correctly identified. It is worth noting, however, that 18% were falsely identified as unemployed, and 14% falsely classified as employed, The WAIS-FSIQ and the MMPI psychopathic deviate scale best predicted the cognitive demands o f the jobs, Jobs requiring perceptual/m otor abilities were associated with good spatial relation test scores and relatively low M M PI depression scores, but not with scores on any o f the m ajor cognitive tests. In general, th e M M PI did not have much predictive utility.
Because the MMPI was less predictive of future em ploym ent (Newm an et al. 1978) than o f current em ploym ent (Heaton & Chelune, 1978), Heaton and his colleagues suggested that cuirent unemployment is associated with negative em otional reaction. Elevations on many scales, particularly depression, they said, could be consequent to prolonged un employment. Wehman, Kreutzer, Stonnington, et al. (1988) noted that brain-injured individuals p'. ..eed through supported em ploym ent program s showed more emotional stability and less depression on the M M PI than did nonplaced referrals.
(c) Participants in rehabilitation programs.
In their follow-up study, Ben-Yishay and colleagues (1987) investigated the relationship between functional, behavioral, and interpersonal process measures and return to work. They did not specify which tests were used. They concluded that o f the five predictors found useful, three were behavioral, psychological, and personality measures, and two w ere measures of cognitive processing.
Prigatano et al. (1986) noted that both the W AIS-Digit Symbol test and the Katz-R adjustm ent scale significantly differentiated between em ployed and unemployed par ticipants who had com pleted the rehabilitation program,
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Wehman, Kreutzer, Stonnington, et al, (1988) found no relationship between the neuro psychological im pairm ent o f placed and nonplaced groups o f brain-injured individuals referred to supported em ploym ent programs,
2. Clinical Judgm ent o f Work A bility
In clinical settings, Psychologists use neuropsychological tests to delineate the cognitive and behavioral consequences of brain injuries, and to predict the likely impact o f deficits on everyday functioning. To determ ine an individual’s ability to work, clinical N euro psychologists rely on their know ledge o f what the tests measure, clinical observations and experience, and reports from occupational trials. Because the tests ere constructed without regard for the abilities successful work performance requires, the vocational im pact o f the deficits observed via testing cannot be determined from inform ation provided by the tests’ psychometric properties (construct or criterion validity), Neuro- psychologists make judgm ents on an individual’s ability to work on the basis o f their experience using the tests and on seeing how the client performs in a rehabilitation setting. Psychologists translate the spared abilities and deficits into general functioning abilities related to work. Experienced clinicians (Heaton & Pendleton, 1981; Kay & Silver, 1988; Lezak, 1987) have assessed work ability by clinically interpreting neuropsychological test data. These clinicians repeatedly stress the need to use qualitative behavioral observations beyond test scores to jud ge a person’s work ability,
Based on present knowledge o f the relationship between neuropsychological tests and w ork ability, even experienced clinicians are limited to general statements. In offering an opinion on a person’s ability to fulfil a specific jo b or work duties within a specific occupational field, a Psychologist can only extrapolate from the deficits observed in the testing situation and the description o f the w ork that’s available. In many instances, Neuropsychologists have limited and general information about jo b demands,
S u m m a ry:
Neuropsychological Assessment of Work Ability
At present, Neuropsychologists usually assess brain-injured individuals’ ability to w ork on the basis o f neuropsychological tests, Although these tests are essential tools, sensitive to neuropsychological dysfunction, they present serious limitations for vocational assessment, In
view o f the lack of criterion-related validity information about the tests, many authors (Clemmons, 1985; Heaton & Chelune, 1978; Prigatano et al. 1986) have pointed out the difficulty o f relating data obtained from neuropsychological tests to specific jobs. The correlational analysis examining the relationship between tests scores and vocational outcom e are generally not based on know ledge of the specific relationship between neuropsychological measures and work demands.
Studies of the predictive ability o f neuropsychological tests have concentrated on em ploy m ent status (employed, unemployed, or underemployed) rather than on job demands. Composite scores are generally better predictors of work status, and greater impairment as measured by neuropsychological tests indicates more problems in the workplace. Without further research including work demands, however, it is difficult to identify the factors explaining the correlations found and if the findings are applicable across occupations. M ost clinicians have limited opportunities to observe individuals in their natural environ ments, or even in rehabilitation settings, There is a definite need for a brief, yet valid m easure of w ork ability that is sensitive to the deficits that follow brain injury. Prigatano, Pepping & Klonoff, in Uzzell & Cross (Eds.), (1986) noted that “if we are going to make recom m endations about the reintegration o f an individual into the com munity following brain damage, based on test results, we need to have a better understanding o f how our current test procedures relate to such aspects o f functioning as job performance and independence in activities o f daily living” (p. 164).
C. Vocational Assessment of Work Ability
By investigating the assessment methods and tools used in vocational counselling, we may be able to increase our ability to use test data in the rehabilitation o f brain-injured persons.
1. J o b M atching
Job matching, the process of analyzing the com patibility o f an indi vidual’s abilities and the dem ands o f a specific occupation or family o f occupations, is an im portant initial step in the vocational counselling and rehabilitation process. To find an acceptable worker-job fit, we m ust assess the abilities deemed necessary to successfully perform work, and know the dem ands o f specific types o f work.
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Commercial com puter job-m atching program?, used in vocational exploration search a database of all available jobs for those that match specific vocational profiles. In vocation al rehabilitation, individuc'job matching is more appropriate, so that job modification can be investigated and work adjustm ent strategics can be developed, In both cases, the dem ands of a considered occup ation are assessed using a job analysis procedure,
2. T h e GATB
The most widely used measure o f work-related aptitude is the General Aptitude Test B attery (GATB). The GATB is available in 13 languages and is used in 35 countries (D roege, 1984). Standardization and validation studies have been conducted in 16 countries. In Canada, it is usually the aptitude test o f choice in government and private vocational rehabilitation agencies.
T he GATB’s relationship to w ork demands as classified by the Canadian Classification an d Dictionary o f O ccupations (CCDO) makes it the most relevant aptitude test available for jo b selection (Botterbusch & M ichael, 1985). A major reference text compiled by the C anada Em ploym ent and Immigration Commission, the CCDO lists more than 7,(XX) Canadian jo b titles and their requirem ents in the areas of physical demands, environmental conditions, general educational development, aptitudes, interests, and temperament. The D ictionary o f Occupational Titles (DOT) is the American counterpart o f the CCDO. T he GATB measures the same nine aptitudes by which the CCDO breaks down occupa tions. A person’s tested abilities can therefore be matched with the criteria listed in the C C D O to select possible occupations w ith aptitude requirements equal to or less than his or her capabilities. Although many cognitive abilities not explicitly measured by the GATB—judgm ent, abstract reasoning, and speed o f processing, for example-—may be im portant to job performance, occupational norms are not yet available for them, The nine aptitudes the GATB does measure, however, have been found to account for much o f the ability judged relevant to the world o f work (Alhelstan, in Kottke, Stillwell & Lehmann (Eds.), 1982).
