The Bender Gestalt and Symbol Digit Modalities Tests as Cerebral Dysfunction Screening Instruments :a Comparative Evaluation

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1 Andrews University Digital Andrews University Dissertations Graduate Research 1984 The Bender Gestalt and Symbol Digit Modalities Tests as Cerebral Dysfunction Screening Instruments :a Comparative Evaluation Bruce R. Wright Andrews University Follow this and additional works at: Part of the Analytical, Diagnostic and Therapeutic Techniques and Equipment Commons, and the Psychology Commons Recommended Citation Wright, Bruce R., "The Bender Gestalt and Symbol Digit Modalities Tests as Cerebral Dysfunction Screening Instruments :a Comparative Evaluation" (1984). Dissertations. Paper This Dissertation is brought to you for free and open access by the Graduate Research at Digital Andrews University. It has been accepted for inclusion in Dissertations by an authorized administrator of Digital Andrews University. For more information, please contact repository@andrews.edu.

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5 W right, B ruce R. THE BENDER GESTALT AND SYMBOL DIGIT MODALITES TESTS AS CEREBRAL DYSFUNCTION SCREENING INSTRUMENTS; A COMPARATIVE EVALUATION Andrews University Ed.D University Microfilms intern et ionel 300 n. zeeb R oad. Ann Arbor. Ml *8106 Copyright 1984 by Wright, Bruce R. All Rights Reserved

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9 Andrews U n iv e rs ity School of E du catio n THE BENDER GESTALT AND SYMBOL DIGIT MODALITIES TESTS AS CEREBRAL DYSFUNCTION SCREENING INSTRUMENTS: A COMPARATIVE EVALUATION A D is s e r ta tio n P re se n te d in P a r t i a l F u lfillm e n t o f th e R equirem ents fo r Che Degree Doctor of E du catio n by Bruce R. W right August 1984

10 THE BENDER GESTALT AND SYMBOL DIGIT MODALITIES TESTS AS CEREBRAL DYSFUNCTION SCREENING INSTRUMENTS: A COMPARATIVE EVALUATION A d i s s e r t a t i o n p re s e n te d in p a r t i a l f u l f i l l m e n t o f th e req u ire m e n ts fo r th e d eg re e Doctor o f E du catio n by Bruce R. W right APPROVAL BY THE COMMITTEE: Chairm an: Selma a J C haij ^ c h o o ^ o f ^Eiucd'txon Committee Member : E. S ta n le y Chace Committee Manber: R o b ert C.^aslSCey D ate approved Commi C^ar^Iegi] W.C.A. F utcher E x te rn a l Exam iner: Conrad A. R e ic h e rt

11 (^ C o p y rig h t by Bruce R. W right 1984 A li R ig h ts Reserved

12 ABSTRACT THE BENDER GESTALT AND SYMBOL DIGIT MODALITIES TESTS AS CEREBRAL DYSFUNCTION SCREENING INSTRUMENTS: A COMPARATIVE EVALUATION by Bruce R. W right Chairm an: Selma A. C haij

13 ABSTRACT OF GRADUATE STUDENT RESEARCH D is s e r ta tio n Andrews U n iv e rs ity School o f E du catio n T i t l e : THE BENDER GESTALT AND SYMBOL DIGIT MODALITIES TESTS AS CEREBRAL DYSFUNCTION SCREENING INSTRUMENTS: A COMPARATIVE EVALUATION Name o f r e s e a r c h e r : Bruce R. W right Name and d eg ree o f f a c u l t y a d v is o r : Selma A. C h a ij, Ph.D. D ate com pleted: A ugust 1984 Problem One of th e problem s c o n fro n tin g th e p s y c h o lo g is t in an i n s t i t u tio n a l s e ttin g i s th e s e l e c t i o n o f a p p r o p r ia te in s tru m e n ts fo r the s c re e n in g and d ia g n o s is o f a v a r i e t y of p s y c h o lo g ic a l p ro b lem s. Among th e more s u b tle and y e t f a r - r e a c h in g problem s o f t h i s s o r t a re th o se a s s o c ia te d w ith d i s e a s e, traum a, or c o n g e n ita l d e f e c t o f th e c e n t r a l nervous system. I t was th e p u rp o se of t h i s stu d y to e v a lu a te th e u s e fu ln e s s of two w ell-know n p s y c h o lo g ic a l t e s t s as s c re e n in g in stru m e n ts fo r n e u ro lo g ic a l d y s fu n c tio n in a la r g e and v a r ie d i n s t i t u t i o n a l p o p u la tio n.

14 Method The Bender V isual-m otor G e s ta lt T est (EOT) and Symbol D ig it M o d a litie s T est (SDMT) were a d m in is te re d to one hundred in c a r c e ra te d m ales from fo u r i n s t i t u t i o n s o p e ra te d by th e Michigan D epartm ent o f C o r r e c tio n s. The a tte n d in g n e u r o lo g is t a t th e p riso n h o s p i t a l had d iag n o sed t h i r t y - f i v e s u b je c ts a s h av in g i n t r a c r a n i a l l e s i o n s, clo se d head traum a, or c h ro n ic c e r e b r a l d is e a s e p ro c e ss, and s i x t y - f i v e a s f r e e from s i g n i f i c a n t c e n t r a l nerv o u s system d is o rd e r. Scores o b ta in e d from th e SDMT and from th e BGT s c o re d w ith th e Main c r i t e r i a w ere compared to optimum c u t- o f f sc o re s p ro v id ed by th e t e s t and sc o rin g method a u th o rs to d eterm in e p re se n c e o r ab sen ce o f b r a in damage in th e sample s u b je c ts. The fre q u e n c ie s o f c o r r e c t d ia g n o se s fo r b oth t e s t s, and fo r th e com bination of th e two t e s t s by adding th e sc o re s to g e th e r, were compared by means of th e C h i-sq u a re s t a t i s t i c fo r c o r r e la te d sam ples. R e s u lts The two t e s t s proved to be v i r t u a l l y o p p o site in t h e i r s e n s i- tiv ijiy. The SDMT was s i g n i f i c a n t l y more s e n s itiv e to th e p re se n c e of b r a in damage in the sam ple s u b je c ts, w h ile the BGT was s i g n i f i c a n t l y more s e n s i t i v e to th e absence of b r a in damage. A d m in is tra tio n o f th e two t e s t s to g e th e r, and a d d itio n o f t h e i r sco res made no s i g n i f i c a n t improvement in th e freq u en cy o f c o r r e c t d ia g n o sis of th e a b s e n s e o f b r a in damage in th e stu d y sam ple, and o n ly a s l i g h t, s t a t i s t i c a l l y i n s i g n i f i c a n t, improvement in th e d ia g n o s is of the p re se n c e o f b ra in damage in th e stu d y sam ple.

15 C onclusions The e x te n t to which the two t e s t s a s s e s s common n e u ro - b e h a v io ra l fu n c tio n s ap p e a rs to be s i g n i f i c a n t l y l e s s th an was expected. The BGT dem onstrated a h ig h e r o v e r a ll p e rc e n ta g e o f c o r r e c t d ia g n o se s, b u t by v i r t u e of i t s g r e a te r s e n s i t i v i t y to th e absence o f b ra in damage in th e sam ple, a ls o produced a h ig h e r f r e quency of f a l s e n e g a tiv e d ia g n o s e s. The SDMI, in c o n t r a s t, dem onstrated a low er o v e r a ll c o r r e c t d ia g n o s tic r a t e and a h ig h e r frequency of f a l s e p o s itiv e d ia g n o s e s. From th e d a ta o b ta in e d, i t ap p ears th a t th e g r e a t e s t d ia g n o s tic a ccu racy can be o b ta in e d w ith th e SDMT a lo n e, or used in co n ju n c tio n w ith o th e r, more c a r f u l l y c o n s tru c te d and s ta n d a rd iz e d t e s t s of v isu o -g rap h o -m o to r n e u ro p sy c h o lo g ic a l f u n c tio n s than th e Bender V isual-m otor G e s ta lt T e s t.

16 TABLE OF CONTENTS LIST OF TABLES... ACKNOWLEDGEMENTS... v v i C hapter I. THE PROBLEM... 1 I n tr o d u c tio n... 1 S tatem en t of th e P r o b le m... 6 P urpose of th e S t u d y... 7 R esearch H ypotheses... 7 A ssum ptions... 7 D e f in itio n of Terms... 9 S ig n ific a n c e of the S t u d y I I, REVIEW OF THE LITERATURE O v e r v ie w H i s t o r i c a l and T h e o re tic a l P e r s p e c tiv e s R esearch in N eu ro p sy ch o lo g ical A s s e s s m e n t R esearch R e la tin g to D evelopm ent and Use of th e Bender G e s ta lt T e s t R esearch w ith th e Symbol D ig it M o d a litie s T e s t S u m m a r y I I I. THE RESEARCH METHODOLOGY O v e r v ie w R esearch D esign S u b je c t S e le c tio n P r o c e d u r e s In s tru m e n ta tio n The Bender G e s ta lt T e s t The Hain Scoring System f o r th e B G T The Symbol D ig it M o d a litie s T e st The N u ll H ypotheses and D ata A n a l y s i s The S t a t i s t i c a l A n aly sis M eth o d o lo g ical L im ita tio n s S u m m a r y IV. PRESENTATION OF THE FINDINGS O v e r v ie w N ull H ypothesis

17 Review o f th e h y p o t h e s i s R e s u lts D i s c u s s i o n N ull H y p o th esis Review o f th e H y p o t h e s i s R e s u l t s D i s c u s s i o n N ull H y p o th esis Review o f th e H y p o t h e s i s R e s u l t s D i s c u s s i o n N u ll H y p o th esis Review o f th e H y p o t h e s i s R e s u l t s D i s c u s s i o n N u ll H y p o th esis Review o f Che H y p o t h e s i s R e s u l t s D i s c u s s i o n N ull H y p o th esis Review o f th e H y p o t h e s i s R e s u lts D i s c u s s i o n S um m ary V, SUMMARY, CONCLUSIONS, AND IMPLICATIONS O v e r v i e w S um m ary F i n d i n g s N ull H y p o th esis N ull H y p o th esis N ull H y p o th esis N ull H y p o th esis N ull H y p o th esis N ull H y p o th esis C o n c l u s i o n s Im p lic a tio n s Im p lic a tio n s fo r C lin ic a l P r a c tic e Im p lic a tio n s fo r F u rth e r R esearch A PPE N D IC E S D e s c rip tio n o f the R esearch P r o je c t C e r t i f i c a t i o n of Informed Consent to P a r t i c i p a t e in N eu ro p sy ch o lo g ical A ssessm ent R esearch R elease o f M edical In fo rm atio n T e s t F ig u re s fo r the Bender G e s ta lt T e s t

18 5. Hain S coring System Manual fo r th e B G T Hain Score sh e e t f o r th e B G T Symbol D ig it M o d a litie s T est F o r m A d m in is tra tio n and Scoring I n s tr u c tio n s fo r th e SDMT A du lt Norms fo r Mean W ritte n and O ral (R e te s t) SDMT S co res by Age Group and E d u c a tio n a l L ev el Memoranda and C orrespondence R e la tin g to D epartm ent o f C o rre c tio n s A pproval of th e P r o j e c t C orrespondence G ran tin g P erm issio n to Reproduce and Use C opyrighted M a te ria ls LIST OF REFERENCES V IT A E

19 LIST OF TABLES 1. Hain S coring System Signs and W eights fo r th e B G T D ata fo r th e C h i-sq u a re A n a ly sis o f th e BGT and SDMT S cores o f Brain-Damaged S u b je c ts D ata fo r th e C h i-sq u a re A n a ly sis of th e BGT and SDMT f l o r e s o f Non-Brain-Damaged S u b j e c t s D ata fo r th e C h i-sq u a re A n a ly sis f o r th e Comparison of th e BGT and BGT+SDMT f o r Brain-Damaged S u b j e c t s D ata fo r th e C h i-sq u a re A n a ly s is fo r th e Comparison of th e BGT and BGT+SDMT fo r Non-Brain-Damaged S u b je c ts Data fo r th e C h i-sq u a re A n a ly sis fo r th e Comparison of th e SDMT and SDMT+BGT fo r Brain-Damaged S u b je c ts Data fo r th e C h i-sq u a re A n a ly sis fo r th e Comparison of th e SDMT and SDMT+BGT fo r Non-Brain-Damaged S u b je c ts... 56

20 ACKNOWLEDGEMENTS To th e M ichigan Departm ent o f C o rre c tio n s fo r t h e i r i n t e r e s t in and su p p o rt of th i s p r o je c t; to D r. R obert R. Walsh f o r th e o r ig in a l s u g g e s tio n of th e re s e a rc h to p ic, and f o r h is kind a s s i s ta n c e in a rra n g in g fo r Departm ent o f C o rre c tio n s ap p ro v al o f th e p r o j e c t, a s w e ll a s in a rra n g in g sc h e d u a ls fo r d a ta c o l le c tio n ; to my m other M rs. Verna W right, my w ife Judy, and our c h ild re n J e f f r e y and R ebecca, whose continued f i n a n c i a l and em o tio n al su p p o rt made th e way so much sm oother; to my com m ittee members, E. S ta n le y Chace, R obert F ad eley, and W. G. A. F u tc h e r, fo r t h e i r h e lp f u l c r i t i c i s m, guid an ce, and c r e a tiv e in s ig h ts ; and to my d i s s e r t a t i o n a d v iso r Selma C h a ij, fo r her optim ism, u n f a ilin g p a tie n c e, and su p p o rt d uring th e p re p a ra tio n of th is stu d y, I e x p re ss my h e a r t f e l t g r a titu d e and a p p r e c ia tio n. VI

21 CHAPTER I THE PROBLEM In tro d u c tio n Development of neuropsychology as a d i s c i p l i n e has e s s e n t i a l l y p a r a lle le d t h a t of the v a rio u s o th e r bran ch es o f psy ch o lo g y. In c h a r a c t e r i z i n g neuropsychology as e x is tin g " a t th e i n t e r s e c t i o n of th e n e u ro sc ie n c e s... and th e b e h a v io ra l s c ie n c e s " (1978, p. 1 ), Hecaen and A lb e rt d i r e c t l y ad d ress t h i s f a c t and s im u lta n e o u s ly p o in t o u t a n o th e r so u rce of n e u ro p sy c h o lo g ic a l developm ent, namely m e d ic in e. In d eed, as one p e ru se s th e h is to r y o f psychology and m e d ic in e, p a r t i c u l a r l y the s p e c ia lty a re a of n e u ro lo g y, one i s s tr u c k by th e l a r g e number of in d iv id u a ls whose names a re common to b o th d i s c i p l i n e s, and whose re s e a rc h has formed the t h e o r e t i c a l b a s is fo r each. As i s th e case in any tru e s c ie n c e, where sy s te m a tic o b s e rv a tio n i s the b a s is fo r in fe re n c e, n europsychology is based upon s y ste m a tic b e h a v io ra l o b s e rv a tio n and a n a ly s is of b e h a v io ra l d i s t u r bances th a t a r e f u n c tio n a lly r e l a t e d to a l t e r a t i o n s in norm al b r a in fu n c tio n. Such a view i s c o n s is te n t w ith a d e f i n i t i o n of n e u ro p sy chology as " th e stu d y of n e u ra l mechanisms u n d e rly in g human b e h a v io r" (Hecaen & A lb e r t, 1978, p. l ). N eu ro p sy c h o lo g ic a l a ssessm en t has developed in re sp o n se to the needs o f v a rio u s d i s c i p l i n e s concerned w ith p s y c h o lo g ic a l fu n c tio n in g. P s y c h ia tr y, C lin i c a l P sy ch o lo g y, C ounseling P sychology, and N eurology have each c o n trib u te d t h e i r 1

22 unique im petus to n e u ro p sy c h o lo g ic a l a sse ssm e n t p r a c t i c e. In th e c l i n i c a l s e t t i n g, the p r a c t i t i o n e r is c a lle d upon to e v a lu a te m an i f e s t b e h a v io r, a sse ss symptom i n t e n s i t y, fo rm u la te d ia g n o s tic im p re s s io n s, and develop rem ed ial p ro c e d u re s. When t h i s s e t t i n g i s such t h a t th e p r a c titio n e r i s con fro n ted w ith la r g e numbers o f p e o p le d is p la y in g a wide v a r ie ty o f n e u ro lo g ic a l o r b e h a v io ra l d i s o r d e r s, some means o f d is c rim in a tin g s t r i c t l y b e h a v io ra l problem s from th o s e th a t a r e n e u ro lo g ic a lly based i s e s s e n t i a l. T h is d i f f e r e n t i a l d ia g n o s tic p ro c e ss may be viewed a s o c c u r r in g in two s ta g e s. The f i r s t s ta g e, or s c re e n in g p h ase, in v o lv e s a more g e n e r a liz e d, broad ap p ro ach. At t h i s l e v e l th e d i a g n o s t i c i a n i s concerned p rim a rily w ith th e n e c e s s ity to d e te rm in e (1) w h e th e r or n o t s i g n i f i c a n t le v e ls of d y sfu n c tio n e x i s t to w arran t f u r t h e r e v a l u a tio n, and (2) what broad c a te g o r ie s of d y s fu n c tio n a re s u s p e c te d. The second phase o f th e p ro cess may be viewed a s a com plim ent to o r l o g i c a l ex ten sio n of th e f i r s t. When i t has been d e te rm in e d th a t a s i g n i f i c a n t n e u r o lo g ic a l problem e x i s t s or is in d ic a te d by th e f in d in g s from the sc re e n in g p ro ced u re, th e a c tu a l d ia g n o s tic p ro c e s s b e g in s. At t h i s le v e l, more s p e c if ic in fo rm a tio n i s so u g h t. Among th e i s s u e s to be s e ttle d a re w hether the problem is p sy c h o g e n ic, neur o l o g i c a l, o r hormonal in o r i g i n. I f i t i s determ ined t h a t th e problem i s e s s e n t i a l l y n e u r o lo g ic a l, the l o c a t i o n, e x te n t, and sp e c i f i c n a tu r e o f the le s io n m ust be determ ined a s a c c u r a te ly a s p o s s i b l e. Lezak (1976) has p o in ted out t h a t such d a ta a r e e s s e n t i a l n o t o n ly to the d ia g n o s tic p ro c e s s, but to th e fo rm u la tio n o f r e h a b i l i t a t i o n p la n s as w e ll. In In approaching t h i s ta sk, the c l i n i c a l p s y c h o lo g is t o r

23 n eu T o p sy c h o lo g ist sh ares much in common w ith th e n e u r o lo g is t. Each is co n cern ed w ith the m a n ife st b e h a v io r of th e p a t i e n t a l b e i t fo r d i f f e r e n t p r a c t i c a l re a so n s, and each r e l i e s, w holly o r in p a r t, upon s y s te m a tic a lly o b ta in e d b e h a v io ra l o b s e rv a tio n s a s t h e i r prim ary d a ta so u rc e. Most o fte n th e se s y s te m a tic b e h a v io ra l o b s e rv a tio n s have tak en th e form of one or a n o th e r t e s t in stru m e n t or b a t t e r y. One common c o n cern shared by both d i s c i p l i n e s i s fo r th e r e s t o r a t i o n of the p a t i e n t to a s near a norm al fu n c tio n in g l e v e l as p o s s ib le. Y e t, in s p ite of th e s e c o m m o n a litie s, th e d if f e r e n c e s between the d i s c i p l i n e s o fte n c r e a te a s i g n i f i c a n t d eg ree o f c o n fu sio n and a m b ig u ity. T his c o n d itio n i s nowhere more a p p a re n t th an in th e d e f i n i t i o n s g iv en to key co n cep ts w hich a r e, in tu r n, d i r e c t l y r e la te d to d i f f e r e n c e s in th e manner in w hich each d i s c i p l i n e ap p ro ach es t h e ir common g o a ls. Smith (1962), in an e x te n s iv e rev iew o f th e th en e x ta n t l i t e r a t u r e of neuropsychology, d i r e c t l y ad d ressed a number o f th e se a m b ig u itie s. W hile c r i t i c a l l y a n a ly z in g re s e a r c h d e s ig n s, in stru m en t a t i o n, and proposed concept d e f i n i t i o n s, he o b serv ed : The in c re a s in g a p p lic a tio n o f p s y c h o lo g ic a l t e s t s in r o u tin e n e u r o lo g ic a l d ia g n o s tic s tu d ie s r e f l e c t s th e u n iv e r s a lly acknowledged fin d in g th a t, however d e f in e d, th e m en tal f u n c tio n s th e se t e s t s a re assumed to m easure a re a p p a re n tly im paired in th e o v e r whelm ing m a jo rity of p a t i e n t s w ith b ra in le s i o n s, (p. 312) Y e t, i t i s p r e c is e ly th e a sse ssm e n t a s p e c t of neuro p sy ch o lo g ic a l d ia g n o s is in which much of th e a m b ig u ity and c o n c e p tu a l c o n fu sio n is p e r p e tu a te d. A b r ie f survey of th e la r g e and grow ing number of n e u ro p s y c h o lo g ic a l t e s t s a v a ila b le le a d s to a re c o g n itio n o f th e accu racy o f S m ith 's o b se rv a tio n even now, more th an tw enty y e a rs l a t e r. Two c o n s id e r a tio n s seem c r i t i c a l in t h i s r e g a rd. F i r s t i s th e f a c t chat many o f Che in stru m en ts even now b ein g used in n e u ro p sy c h o lo g ic a l

24 s c re e n in g and d ia g n o s is, p a r t i c u l a r l y th o se th a t were developed and sta n d a rd iz e d e a r l i e r than d u rin g th e l a s t te n or tw enty y e a r s, w ere pro b ab ly d esig n ed fo r such p u rp o ses a s i n t e l l e c t u a l or p e r s o n a lity a ssessm en t. S econdly, i t must be k e p t in mind th a t no d i r e c t l i n k between s p e c if ic n e u ra l c e l l a s s e m b lie s and m a n ife st b eh av io r has ev er been c o n c lu s iv e ly e s ta b lis h e d. H ence, th e d ia g n o s tic ia n i s e v a l u a tin g b e h a v io ra l c o r r e l a t e s of n e u ro p s y c h o lo g ic a l or e le c tro c h e m ic a l e v e n ts r a th e r th a n th e e v e n ts th e m se lv e s. Thus, to th e a lre a d y e x i s t ing problem s o f c o n c e p tu a l am b ig u ity and c o n fu sio n, th e c l i n i c i a n adds th e r i s k o f e r r o r r e l a t e d to i n d i r e c t m easurem ent. A sso c ia te d w ith the tr a d e - o f f betw een b read th of co v erag e and p r e c is io n a lr e a d y n o te d, the d e g re e o f o v e rla p between two o r more in stru m e n ts used in c o n ju n c tio n w ith one a n o th e r a lso c o n fro n ts th e c l i n i c i a n. T hat i s, th e t e s t s may be view ed a s o v e rla p p in g to th e e x te n t th a t th e y a re m easuring th e same n e u ro p sy c h o lo g ic a l e v e n ts. W hile d i f f e r e n t t e s t s a re u n lik e ly to o v e rla p co m p letely, i f th e y a re m easuring sh ared b e h a v io rs some d e g re e of o v e rla p can be a n t i c i p a t e d. O bviously th e n, th e re i s an in v e rs e r e l a t i o n s h i p between th e e x te n t of o v erlap (th e e x te n t to which th ey a l l m easure the same th in g s ) between two or more t e s t s and t h e i r combined d is c rim in a tin g pow er. A lthough developm ent of some s in g le " b e s t" t e s t or b a t t e r y fo r sc re e n in g o r d ia g n o sin g b ra in damage h as lo n g been an i n t r i g u i n g p ro s p e c t, to d a te no such b a tte r y o r t e s t has been produced. In s p i t e of c o n tin u in g r e s e a r c h and developm ent t h a t has produced numerous t e s t s and b a t t e r i e s d e sig n e d fo r a s s e s s in g v a r io u s types of n e u r o lo g ic a l d y s fu n c tio n, none has achieved u n iv e r s a l a c c e p ta n c e. M oreover, in s p i t e of in c re a s in g s o p h is tic a tio n in b o th in stru m e n ts and e v a lu a tio n

25 p ro c e d u re s, th e n e u ro p s y c h o lo g is t s t i l l m ust r e l y upon m easurem ent of the b e h a v io ra l c o r r e l a t e s o f n e u ra l e v e n ts r a t h e r th an th e n e u ra l ev en ts th em selv es fo r d a ta, and he or she s t i l l o f te n r e l i e s upon te s t s th a t w ere desig n ed and s ta n d a rd iz e d fo r o th e r u s e s. Some of th e se in s tru m e n ts have become so w idely used in n e u ro p sy c h o lo g ic a l assessm en t, t h a t they have a c q u ire d " s ta n d a rd " s t a t u s. In many c a se s th ese t e s t s have re p e a te d ly d em o n strated a c c e p ta b le l e v e l s o f v a l i d i t y and r e l i a b i l i t y in n e u ro p sy c h o lo g ic a l d ia g n o s tic a p p l i c a t i o n s. In th e p re s e n t s tu d y, a s id e from g e n e ra l t h e o r e t i c a l c o n s id e r a tio n s e s s e n t i a l to u n d e rsta n d in g h i s t o r i c a l p e r s p e c tiv e s and e v a lu a tin g th e c u rre n t s t a t u s o f th e n e u ro p s y c h o lo g ic a l assessm en t f i e l d, th e fo c u s i s e s s e n t i a l l y e m p iric a l. The two t e s t s to be compared may be viewed as r e p r e s e n t a t i v e, in a se n s e, of th e two c la s s e s of d ia g n o s tic t e s t s j u s t n o te d. The Bender V isu al-m o to r G e s ta lt (h e r e a f te r r e f e r r e d to as th e Bender G e s ta lt T e s t, th e Bender G e s ta lt, or sim ply th e BGT) has co n tin u e d to enjoy wide p o p u la r ity among c l i n i cia n s even in th e fa c e of c o n tin u in g e q u iv o c a l e v id en ce re g a rd in g i t s u s e fu ln e s s a s a n e u ro d ia g n o s tic in stru m e n t and in s p i t e of o r i g i n a l l y being d e sig n e d fo r o th e r u s e s. On th e o th e r hand, th e Symbol D ig it M o d a litie s T e st (SDMT), a c a r e f u l l y d esig n ed and s ta n d a rd iz e d t e s t s p e c i f i c a l l y in ten d ed fo r n e u ro d ia g n o s tic u se, i s su p p o rted by a growing body of r e s e a rc h a t t e s t i n g to i t s v a l i d i t y and r e l i a b i l i t y. A d d itiv e o r s u b tr a c tiv e s e le c tio n i s one p r a c t i c a l consequence of e v a lu a tio n, and s e le c tio n o f th e m ost p a rsim o n io u s, econom ical, and e f f e c t i v e t e s t s p o s s ib le i s a problem faced by every c l i n i c i a n. In a c l i n i c a l s e t t i n g, such c o n cern s a re o f somewhat g r e a te r importance than i s th e s p e c if ic t h e o r e t i c a l h e r ita g e of th e t e s t o r b a tte r y.

26 I t i s w ith in t h is g e n e ra l c o n te x t th a t the p r e s e n t study a d d re sse d th e q u e s tio n of the v a l i d i t y and r e l i a b i l i t y of th e s e two w id ely used psyc h o lo g ic a l t e s t s when used a s n e u ro p sy c h o lo g ic a l sc re e n in g in s tru m e n ts e i t h e r in d iv id u a lly or in co m b in atio n. S ta te m e n t o f th e Problem Exam ination o f th e Bender G e s ta lt and Symbol D ig it M o d a litie s t e s t s su g g e sts th a t b o th in s tru m e n ts tap common v is u a l- m o to r, v i s u a l - p e r c e p tu a l, i n t e g r a t i v e, and c o o rd in a tio n s k i l l s. At th e same tim e, w hereas th e Bender G e s ta lt i s p e rh a p s more in v o lv e d in e l i c i t i n g in fo rm a tio n about p e rc e p tu a l q u a l i t i e s, the Symbol D ig it M o d a litie s T e st ap p ears p a r t i c u l a r l y s e n s i t i v e to d e f i c i t s in la n g u a g e -re la te d sym bolic fu n c tio n s and n o n -lan g u ag e a b s t r a c t sym bolic c o g n itiv e fu n c t i o n s. To th e e x te n t t h a t th e two t e s t s do n o t o v e rla p th e n, a h ig h e r deg ree of d is c rim in a tin g power may be expected from the combined use of th e two t e s t s. In th e face of f in d in g s to be p re se n te d in c h a p te r I I, i t is somewhat s u rp ris in g t h a t, a lth o u g h i t has been su g g ested t h a t use of Che two t e s t s to g e th e r would p ro v id e a u s e f u l, q u ic k sc re e n in g b a t t e r y fo r use in a neurology p r a c t i c e (C a n te r, 1978), a p p a re n tly no a tte m p t has been made to d i r e c t l y compare th e two t e s t s o r to a s s e s s the d eg ree of o v erlap betw een them, i f any. N e ith e r has th e re a p p a re n tly been any attem p t to d i r e c t l y compare th e p erform ance of th e two t e s t s u sin g th e same sample o f s u b j e c t s. In a tte m p tin g to a d d re ss b o th of th e above is s u e s, th e p r e s e n t stu d y y ie ld e d d a ta r e le v a n t to th e u t i l i t y of both in stru m e n ts used in d iv id u a lly or to g e th e r to e v a lu a te n e u ro lo g ic a l d y s fu n c tio n. M oreover, th e stu d y p ro v id ed a means of f u r th e r te s tin g of S m ith 's a s s e r t i o n (c ite d in W alker, 1983) th a t

27 7 "The SDMT is pro b ab ly Che m ost econom ic, s e n s i t i v e, v a l i d and u s e f u l s in g le t e s t fo r d i f f e r e n t i a l d ia g n o s is and fo r g e n e ra l c l i n i c a l a sse ssm e n t" (p. 485). Purpose of th e Study The purpose of t h i s stu d y was to e v a lu a te th e a b i l i t y o f th e Bender G e s ta lt and Symbol D ig it M o d a litie s t e s t s to d is c r im in a te b r a in damaged s u b je c ts r e p r e s e n tin g a broad spectrum o f e tio lo g y, ty p e, e x te n t, and lo c u s o f le s io n from non-brain-dam aged s u b je c ts. R esearch Hypotheses In o rd e r to p ro v id e fo c u s and d ir e c t i o n to th e c u r r e n t s ty d y, two re s e a r c h h y p o th eses w ere proposed: 1. The SDMT w i l l d is c r im in a te th e p re se n c e o r absence of b r a in damage in th e sam ple s u b je c ts s i g n i f i c a n t l y b e t t e r than th e Bender G e s ta lt T est when th e two a re used i n d iv id u a lly. 2. Combining Che o b ta in e d sco res fo r th e two t e s t s w i l l p ro d u ce a s i g n i f i c a n t l y h ig h e r freq u en cy o f c o r r e c t d ia g n o se s o f th e p re se n c e o r absence o f b r a in damage than w ill be o b ta in e d by e i t h e r t e s t used a lo n e. Assumptions I d e a lly, in r e s e a r c h en d eav o rs, a l l v a r i a b l e s e x c e p t th e e x p e rim e n ta l v a r ia b le or v a r i a b l e s a re c o n tr o lle d by some means so t h a t a c a u s e - e tf e c t r e l a t i o n s h i p can be p o s ite d betw een th e tre a tm e n t p ro c e d u re and observed change in th e ex p erim en tal v a r i a b l e. In p r a c t i c e how ever, such a s tr a ig h tf o r w a r d procedure i s seldom p o s s ib le. T his i s p a r t i c u l a r l y tr u e in s o c ia l o r e d u c a tio n a l r e s e a r c h, where the u se of human s u b je c ts p re c lu d e s a b s o lu te c o n tr o l of a l l p o t e n t i a l l y

28 8 r e le v a n t v a r ia b le s. When such c o n d itio n s p r e v a il, the r e s e a r c h e r Is c a lle d upon to d e s ig n c o n tr o ls In to h is p ro ced u res by means o f s p e c ia l s u b je c t s e le c tio n te c h n iq u e s, s t a t i s t i c a l tre a tm e n t of th e d a t a, and by th e accep tan ce o f c e r t a i n a p r i o r i assum ptions re g a rd in g th e n a tu r e, r e l a t i o n s h i p, and r e l a t i v e In flu e n c e of any known u n c o n tro lle d v a r i a b le s upon th e outcom es o f th e stu d y. The p re s e n t stu d y u n av o id ab ly In c o rp o ra te d a somewhat c i r c u l a r r e la tio n s h ip betw een th e c r i t e r i o n and e x p e rim e n ta l v a r i a b l e s. That I s, th e n e u r o lo g is t. In e s ta b lis h in g a d ia g n o s is of th e p re s e n c e o r absence of b ra in damage, f r e q u e n tly r e l i e s upon n e u ro p sy c h o lo g ic a l t e s t r e s u l t s to g u id e In th e f i n a l d ia g n o s is, and I t may be t h a t In some cases one or th e o th e r o f th e two t e s t s being e v a lu a te d In th e p re s e n t study p ro v id ed p a r t o f th e d ia g n o s tic d a ta. A gain, v a r ia n c e s In c l i n i c i a n com petence and tho ro u g h n ess In perform ing e v a lu a tio n s fo r such d ia g n o s tic d a ta w ere beyond th e c o n tr o l of t h i s r e s e a r c h e r. Because th e p r e s e n t stu d y was d esigned to ap proxim ate a s c re e n in g p ro c e d u re, w h erein such In fo rm a tio n as p re v io u s c o n ta c t w ith a n e u r o lo g is t o r e v a lu a tio n by a n e u ro p sy c h o lo g ist was u n a v a ila b le or a t b e st In c o m p le te, c o n tro l of th e se v a r ia b le s was Im p o ssib le. The re s e a rc h e r was th u s fo rc e d to d e lin e a te assum ptions re g a rd in g them. For th e p u rp o se s o f th e p re s e n t s tu d y, fo u r a p r i o r i assumptio n s were made: 1. D iag n o sis of c e r e b r a l d y sfu n c tio n or b ra in damage by a q u a lif ie d n e u r o lo g is t Is t a c i t evidence o f b ra in damage In th e su b j e c t s so d iag n o sed. 2. D ia g n o sis of no s i g n i f i c a n t d is o r d e r or traum a by a

29 q u a lif ie d n e u r o lo g is t i s t a c i t ev idence th a t th e s u b je c t so diag n o sed is fre e o f s i g n i f i c a n t b ra in damage. 3. P rio r knowledge of th e n a tu re of th e r e s e a r c h as a fu n c tio n of th e inform ed c o n se n t p ro v is io n s of the stu d y w i l l have no a p p re c ia b le e f f e c t, p o s i t i v e o r n e g a tiv e, upon t e s t perfo rm an ce. 4. The s p e c i f i c n a tu r e o f any p a r t i c u l a r n e u ro p s y c h o lo g ic a l t e s t s o r t e s t b a t t e r i e s used to a s s i s t the n e u r o lo g is t in a r r i v i n g a t the f i n a l d ia g n o s is w i l l have no a p p re c ia b le e f f e c t upon th e outcom es of the c u r r e n t t e s t i n g p ro c e d u re. D e f in itio n of Terms R ecognizing t h a t th e p re s e n t study in t r u d e s, to a d e g re e, upon s e v e r a l d i s c i p l i n e s and t h a t confusion r e l a t i n g to th e meaning or use o f sh ared term s o r c o n c e p ts thus becomes l i k e l y, the fo llo w in g o p e r a tio n a l d e f i n i t i o n s a re o ffe re d fo r c e r t a i n o f th e s e term s used in the p r e s e n t stu d y. B rain Damaged - s h a ll r e f e r to a f u n c tio n a l d im in u tio n o r lo s s r e l a t e d to i n t r a c r a n i a l le s io n o r trauma r e g a r d l e s s of e tio lo g y. C e re b ra l Im pairm ent - s h a ll be co n sid ered an e q u iv a le n t of b ra in damage and s h a l l be so d e fin e d. Demographic F a c to rs - s h a ll r e f e r to a h i s t o r y of head i n j u r y, b ra in d i s e a s e, c o n g e n ita l anom aly, chronic a lc o h o lis m, o r lo n g -te rm su b sta n c e abuse in th e ab sen ce of an accompanying d ia g n o s is of b r a in damage. D ia g n o sis - s h a l l be u n derstood to mean an e x h a u s tiv e and thorough n e u ro p s y c h o lo g ic a l e v a lu a tio n designed to l o c a l i z e and e v a l u a te a su sp e c te d le s i o n and th e a s s o c ia te d b e h a v io r a l d e f i c i t s. S creen in g - s h a l l be understood to r e f e r e i t h e r to the t e s t s

30 10 or to th e p ro cess in v o lv ed in a s c e r ta in in g w hether or not s i g n i f i c a n t le v e l s of n e u ro lo g ic a l d e f i c i t e x is t in the s u b je c t to w a rra n t f u r th e r d ia g n o s tic r e f e r r a l. Standard S coring - s h a l l r e f e r to the u se of the s c o r in g p ro ced u re s fo r a given t e s t, developed by the t e s t a u th o r or p u b l i s h e r, or to sta n d a rd iz e d s c o rin g m ethods developed f o r a g iven t e s t by p e rso n s o th e r than the o r i g i n a l t e s t au th o r or p u b lis h e r. S ig n if ic a n c e o f the Study The l i t e r a t u r e re v ie w to be p re se n te d in c h a p te r I I r e v e a l s th a t th e f i e l d of n e u ro p s y c h o lo g ic a l assessm en t is c h a r a c te r iz e d a t th e p re s e n t tim e by c o n d itio n s of f lu x. I t has been a s s e r te d t h a t th e d i s c i p l i n e is in i t s in fa n c y. M oreover, i t has been su g g e ste d t h a t, alth o u g h one can lo o k back some seventy y e a rs e v a lu a tin g th e f i e l d 's developm ent, p r o g r e s s has been slow. C o ro lla ry to t h i s a s s e r tio n i s th e n o tio n th a t a v a i l a b l e measurement te c h n iq u e s a re t h e r e f o r e somwhat crude by com parison to th o se a v a ila b le to th e more "m a tu re " d i s c i p l i n e s. While v ary in g d e g re e s of refin em en t and s o p h i s t i c a t i o n may be found in the v a rio u s t e s t s a v a ila b le to the n e u ro p sy c h o lo g ic a l d ia g n o s tic ia n or r e s e a r c h e r, th e f a c t s t i l l rem ains th a t in n e u ro p sy ch o lo g i c a l assessm en t, b e h a v io ra l c o r r e la te s of n e u ra l p ro c e s s e s and n o t th e p ro c e s s e s them selv es c o n tin u e to be m easured. The two t e s t s used in th e p re s e n t study in a se n se r e p r e s e n t an " e a r ly ", more i n t u i t i v e, p erh ap s l e s s w e ll- s ta n d a r d iz e d in stru m en t (th e Bender G e s ta lt T e s t) which c o n tin u e s to be u s e d, and a more r e c e n tly developed in s tru m e n t (th e Symbol D ig it M o d a litie s T e st) th a t has been s p e c i f i c a l l y d e sig n e d

31 11 to d is c r im in a te n e u ro lo g ic a l d e f i c i t s. Even as th e two t e s t s to some e x te n t r e p r e s e n t d i f f e r i n g f o c i, they a r e a ls o among the most w id e ly used t e s t s in n e u ro p sy c h o lo g ic a l sc re e n in g, and a re o fte n in c lu d e d in d ia g n o s tic b a t t e r i e s. T h e re fo re, in l i g h t of th e o fte n c o n f l i c t i n g f in d in g s re p o rte d in th e v a rio u s co m p arativ e s t u d i e s, and p a r t i c u l a r l y th e fre q u e n t c r i t i c i s m o f th e co n tin u ed use o f th e Bender G e s t a l t T e st a s a s c re e n in g o r d ia g n o s tic in s tru m e n t, th e f in d in g s from th e stu d y p ro v id e a d d i t i o n a l d a ta re g a rd in g th e r e l a t i v e e f f ic a c y o f b o th t e s t s fo r such a p p l i c a t i o n s. Beyond t h i s, th e stu d y f u r t h e r illu m i n a t e s is s u e s o f n eu ro p sy ch o lo g i c a l assessm en t in h e re n t in th e somewhat d i f f e r e n t n a tu r e s o f th e two t e s t s, and th u s th e p o t e n t i a l l y d i f f e r e n t n e u ro p sy c h o lo g ic a l p ro c e sse s e v a lu a te d. F in a lly, th e stu d y te n d s to su p p o rt r a t h e r th an c a l l in to f u r t h e r q u e s tio n th e a s s e r t i o n o f Sm ith ( c ite d in W alker, 1983) th a t "The SDMT i s p ro b ab ly th e m ost econom ic, s e n s i t i v e, v a l i d and u s e fu l s in g le t e s t fo r d i f f e r e n t i a l d ia g n o s is and fo r g e n e ra l c l i n i c a l asse ssm e n t" (p ), and th e s u p p o rtin g o p in io n o f B ig le r and E h rfu rth (1980) th a t " r e g a r d le s s o f how th e BG i s sco red or a n a ly z e d, as a s in g le m easure or a s an a d ju n c t sc re e n in g m easure... i t s c l i n ic a l u se as a n e u ro d ia g n o s tic te c h n iq u e i s sp ecio u s a t b e s t ' (p. 5 8 ).

32 CHAPTER II REVIEW OF THE LITERATURE Overview Reviewing e x is tin g l i t e r a t u r e r e l a t i n g to a g iv e n re s e a r c h problem p r e s e n ts th e r e s e a r c h e r w ith a number of dilem m as. On th e one hand i s th e o b lig a tio n to rev iew and p re s e n t r e s e a r c h w hich b e a rs d i r e c t l y upon the q u e s tio n under c o n s id e r a tio n. On th e o th e r h an d, redundancy o r r e p e t i t i o n se rv e s no u s e fu l p u rp o se. The p r e s e n t rev iew should be viewed as r e p r e s e n t a t i v e r a th e r th an e x h a u s tiv e in th e se n se th a t the l i t e r a t u r e c it e d p ro v id e s s u f f i c i e n t b re a d th to e s t a b l i s h th e n e c e ssa ry h i s t o r i c a l and t h e o r e t i c a l m ilie u f o r th e s tu d y, and a ls o a re a so n a b ly com prehensive review o f c u r r e n t r e s e a r c h in n eu ro p s y c h o lo g ic a l a sse ssm e n t. A lthough em phasis has been p laced upon s tu d ie s in v o lv in g one o r th e o th e r of th e t e s t s b eing e v a lu a te d in th e p re s e n t s tu d y, f u r th e r r e s e a rc h u t i l i z i n g o th e r in s tr u m e n ts, b u t b e a r ing g e n e ra lly upon is s u e s of n e u ro p sy c h o lo g ic a l a sse ssm e n t or n e u ro - d ia g n o s tic problem s, have been in c lu d e d. In th e p re s e n t rev iew a d is c u s s io n o f so u rc e s r e l a t i n g to h i s t o r i c a l and th e o r e t i c a l developm ent and s tu d ie s g e n e r a lly r e l a t e d to n e u ro p sy c h o lo g ic a l a ssessm en t a re follow ed by s e c tio n s p re s e n tin g s tu d ie s r e l a t e d to the developm ent and u se o f th e Bender G e s ta lt T e s t, v a rio u s o b je c tiv e s c o rin g system s fo r th e Bender G e s t a l t, and f i n a l l y. 12

33 13 studies dealing with the development and use of Che Symbol Digit Modalities Test. H is to r ic a l and T h e o r e tic a l P e rs p e c tiv e s A lthough i t is p o s s ib le to tr a c e th e developm ent of n e u ro p sy c h o lo g ic a l assessm ent from a n t i q u i t y, to do so in th e c o n te x t of th e p r e s e n t study would add l i t t l e to u n d e rsta n d in g th e c u r r e n t pro b lem. H ence, o n ly cu rso ry a t t e n t i o n i s g iv en to h i s t o r i c a l is s u e s p r i o r to th e b eg in n in g of th e n in e te e n th c e n tu ry and to p h ilo s o p h ic a l t r e n d s o n ly to th e e x te n t of e s t a b l i s h i n g th e prim ary sch o o ls o f n e u r o lo g ic a l o r n e u ro p sy c h o lo g ic a l th o u g h t in th e tw e n tie th c e n tu ry. W ertheim er (1979) speaks to t h i s is s u e in sum m arizing the h i s t o r i c a l r o o ts o f e x p e rim e n ta l psychology, and th u s i n d i r e c t l y of neuropsychology a s w e ll, when he says:... a lth o u g h th e o r i g i n s of many of th e tre n d s c u lm in a tin g in th e ex p erim en tal psychology o f 1860 and beyond, can be seen in G reek and p r e - r e n a is s a n c e th o u g h t, i t is p rim a rily th e h i s t o r y o f id e a s sin c e the r e n a is s a n c e which c a s ts l i g h t upon th e a c a dem ic o r t g e i s t and Z e i t g e i s t o f m id -n in e te e n th c e n tu ry E urope, w here ex p erim en tal p sy chology was bo rn. (p. 49) In this regard, one can consider five lines of development in scientific thought that bear directly upon the problem at hand. From physiology came the demonstration of anatomic differences between sensory and motor neurons, the study of the electrical nature of nerve impulses, development of the neuron theory, and the growing controversy between globalist and localizationist explanations for observed neurological phenomena. From biology and natural history came Darwin's concepts of natural selection which led directly to the theory of evolution, and revolutionized scientific thought. From physics came the atomic theory of matter, and from mathematics came more

34 14 s o p h is tic a te d q u a n tif ic a tio n based on knowledge produced in th e d e v e l oping f i e l d of s t a t i s t i c s. F in a lly, th e re was in Europe a t th a t tim e, a s tro n g tendency toward academ ic dominance in most s c i e n t i f i c in v e s t i g a tio n. T hat i s, most of th e re s e a rc h of th e tim e tended to be done in academ ic s e t t i n g s or under th e a u s p ic e s o f u n i v e r s i t i e s, an o b s e r v a tio n to which e s ta b lis h m e n t of a la b o r a to r y by W ilhelm Wundt a t the U n iv e rs ity o f L eip zig in 1879 b e a rs w itn e s s. The in flu e n c e of a l l th e se v a rio u s f a c t o r s may be tra c e d in th e f i e l d s o f neurology and n europsychology. A dom inant c o n tro v e rsy has been betw een g l o b a l i s t and l o c a l i z a t i o n i s t view s o f n e u ro lo g ic a l phenomena. In g e n e ra l te rm s, th e l o c a l i z a t i o n i s t p o s itio n i s th a t any b e h a v io ra l m a n if e s ta tio n th a t may be observed in v o lv e s a more or l e s s s p e c if ic n e u ra l lo c u s, w hereas th e g l o b a l i s t p o s itio n i n t e r p r e t s th e s e same phenomena from an a ll-e n c o m p a ssin g, e s s e n t i a l l y u n ita r y c o n c e p tu a liz a tio n o f th e nerv o u s system. W hile th e modern o b se rv e r w ith th e b e n e f it of h is to r y and of th e p o s t- r e n a is s a n c e s c i e n t i f i c r e v o lu tio n to aid h is p e r c e p tio n, may conclude t h a t each p o s itio n c o n tr ib u te s some s i g n i f i c a n t co n cep ts to c u rre n t u n d e rs ta n d in g s of nervous system fu n c tio n, such e c le c tic is m has not alw ays p re v a ile d. In deed, the h i s t o r i c a l developm ent of neuropsychology has w itn essed an ebb and flow in the in f lu e n c e of each p o s itio n. R eise (1959) speaks of "Rufus of Ephesus... th e f i r s t medi c a l w r ite r th a t adopted a g lo b a l view of th e nervous system " (p. 2 7 ). T h is view of th e nervous system ap p ears to have dom inated n e u ro lo g ic a l th o u g h t more o r le s s c o n s i s t e n t l y u n t i l th e m iddle of th e n in e te e n th c e n tu ry, when the mounting body of ex p e rim e n ta l r e s e a r c h began to more c le a r l y su p p o rt th e co n cep t of lo c a l i z a t i o n of f u n c tio n. In a

35 15 b r i e f rev iew of the h is to r y o f n eu ro p sy ch o lo g y, Hecaen and A lb e rt (1978) a s s e r t th a t: The l o c a l i z a t i o n i s t s can d a te th e b e g in n in g o f t h e i r movement as A p r il 18, 1861, when Broca d e sc rib e d a p a tie n t who had l o s t th e f a c u lty of a r t i c u l a t e d language and who had a l e f t h em isp h ere l e s i o n. Broca concluded th a t th e p o s t e r i o r - i n f e r i o r p o r tio n of th e f r o n t a l lobe c o n tr o lle d t h i s b e h a v io ra l f a c u lty, (p. 14) F ranz G a l l 's d o c tr in e of o rg an o lo g y, l a t e r re fin e d and r e c h r is te n e d "phrenology" by h is p u p il Spurzheim, may be view ed a s a p re c u rs o r o f th e l o c a l i z a t i o n i s t approach a lth o u g h h is work l a t e r came to be re g a rd e d as p s e u d o s c ie n tif ic. However, i t i s in th e work o f B ro ca, no ted above, and th e l a t e r work of W ernicke (c ite d in Hecaen & A lb e r t, 1978, p. 14) th a t l o c a l i z a t i o n i s t th e o ry found e a r ly and p e rh a p s i t s s tr o n g e s t s u p p o rt. Y e t, even as th e l o c a l i z a t i o n i s t movement was g a in in g s t r e n g t h and b e g in n in g to dom inate n e u ro p s y c h o lo g ic a l th o u g h t d u rin g th e l a t t e r p a r t o f th e n in e te e n th c e n tu r y, o th e r i n v e s t i g a t o r s were r e p o r tin g f in d in g s w hich ch allen g ed th e dom inant v ie w p o in t, and which s e t in to m o tio n i n t e l l e c t u a l and t h e o r e t i c a l f o rc e s th a t would e v e n tu a lly f o r c e a r e t u r n to more g l o b a l i s t i c view s o f n e u ra l fu n c tio n. W ertheim er (1979) n o te s th e work of P i e r r e F lo u ren s who ab o u t 1820 moved away from th e extrem e l o c a l i z a t i o n i s t view s e x e m p lifie d by th e p h re n o l o g i s t s. F lo u re n s "... used th e method of e x t i r p a t i o n ( s u r g ic a l r e m o v a l), stu d y in g th e r e l a t i o n o f lo s s o f b r a in t i s s u e to changes in b e h a v io r, and concluded t h a t th e b r a in a c ts e s s e n t i a l l y as a w h ole, a lth o u g h c e r t a i n lo b es do have f a i r l y s p e c i f i c f u n c tio n s " (p. 2 7 ). The l o c a l i z a t i o n i s t p o s itio n c o n tin u e d to dom inate n e u ro p sy c h o lo g y, b u t a growing u n d e rc u rre n t of g l o b a l i s t r e s e a r c h c h a r a c t e r iz e d th e f i e l d u n t i l a f t e r World War I had ended. Perhaps as a

36 16 fu n c tio n of th e sim ple accu m u latio n o f on-going re s e a r c h begun p r io r to the w ar, b u t more l i k e l y in flu e n c e d by o b s e rv a tio n s o f b r a in damage among r e tu r n in g servicem en, an abandonm ent o f extrem e l o c a l i z a t i o n i s t p o s itio n s came a b o u t. The tre n d tow ard a more h o l i s t i c view of n e r vous system fu n c tio n begun by F lo u re n s th u s r e s u l t e d, a c e n tu ry l a t e r, in a r e a s s e r t i o n of g l o b a l i s t th e o ry. Many f a c to r s d o u b tle s s c o n tr ib u te d to t h i s change, but Heilman and V a le n s te in (1979) s i n g l e o u t th e d i s c r e d i t i n g o f phrenology as a c o re f a c t o r, su g g e stin g t h a t by i t "... o th e r l o c a l i z a t i o n i s t th e o r ie s became s u sp e c t" (p. 2 7 ). The more h o l i s t i c tre n d in n e u ro p s y c h o lo g ic a l r e s e a r c h begun by F lo u ren s and co n tin u ed a f t e r World War I, i s p erh ap s now here b e t t e r ex em p lified th an in th e work of K arl L a sh le y, who in 1938 proposed h i s theory o f mass a c tio n. T his fo rm u la tio n s t a t e s th a t "The b e h a v io ra l r e s u l t o f a le s i o n depends on th e amount o f b ra in removed more th an on the l o c a tio n of th e le s io n " ( c ite d in Heilman & V a le n s te in, 1979, p. 7 ). In t h e i r own d is c u s s io n o f th e e f f e c t of b r a in l e s i o n s upon lan g u ag e, Hecaen and A lb e rt (1978, p. 35) echo t h is p o s i t i o n. D uring th e y e a rs s in c e th e end of World War I, th e two p r i n c i p a l sch o o ls o f neuropsychology have c o n tin u e d to d e v e lo p. In a d d itio n to L a s h le y 's work noted above, th e em erging school o f G e s t a l t p sy c h o l ogy seems to have had a pronounced e f f e c t upon m id - tw e n tie th c e n tu ry n e u ro p sy c h o lo g ic a l th e o ry. C e r ta in ly, th e m a s s -a c tio n th e o ry and th e n o tio n o f t o t a l o rg a n iz a tio n d e riv e d from G e s ta lt th e o ry had th e e f f e c t o f f u r t h e r d i l u t i n g th e p o ten cy of th e l o c a l i z a t i o n i s t p o s i t i o n. However, in th e p e rio d betw een th e two w orld w ars "... th e two m ain sch o o ls o f th o u g h t... came to lo s e a l l h e u r i s t i c v a lu e by t h e ir