Computer aided treatment of patients with injuries of the spinal cord

376

-COMPUTER AIDED TREÄTMENT OF PATIENTS WITH INJURIES OF THE SPINAL CORD

by

H.G. S t a s s e n , A. van L u n t e r e n , R. Hoogendoorn,

G.J. van d e r K o l k , P. B a l k , G. M o r s i n k , J.C. Schuurman. D e l f t , U n i v e r s i t y o f T e c h n o l o g y , D e p t . o f Mech. Eng.

Lab. f o r Measurement and C o n t r o l , Man-Machine Systems Group, D e l f t , The N e t h e r l a n d s .

A b s t r a c t

The r e h a b i l i t a t i o n p r o c e s s o f s p i n a l c o r d i n j u r y p a t i e n t s i s c a r r i e d out by a m u l t i d i s c i p l i n a r y team. Such a s t e p a s s u r e s t h a t a l l d a t a needed f o r t h e t r e a t m e n t a r e a v a i l a b l e ; however, I t a l s o créâtes the p r o b l e m o f t h e exchange o f a c c u r a t e and u p - d a t e d i n f o r m a t i o n t o a l l members o f t h e team.

In o r d e r t o s o l v e t h i s p r o b l e m a s t u d y o f t h e e n t i r e r e h a b i l i t a t i o n p r o c e s s bas been made; t h a t i s t h e dynamics o f t h e t r e a t m e n t i t s e l f have been m o d e l l e d , and the i n f o r m a t i o n streams i n r e l a t i o n t o the o r g a n i s a t i o n s t r u c t u r e have been t r a c e d .

In a p p l y i n g the model d e v e l o p e d , a d i g i t a l Computing f a c i l i t y has t o be

i n t r o d u c e d i n the r e h a b i l i t a t i o n c e n t e r . In o r d e r t o be aware o f t h e conséquences o f such an i n t r o d u c t i o n a s t u d y o f t h e i n f o r m a t i o n f l o w s and o f t h e o r g a n i s a t i o n has t o be e x e c u t e d , s i n c e i t i s i m p o r t a n t t o know how s t r o n g l y a u t o m a t i o n o f the d a t a p r o c e s s i n g c o u l d a c t on t h e f u n c t i o n i n g o f t h e i n d i v i d u a l s t a f f members. F i n a l l y , t h e conséquences as f a r as t h e y can be o v e r l o o k e d a t t h i s moment w i l l be d i s c u s s e d . A f i r s t e x p e r i m e n t w i t h t h e i n t r o d u c t i o n o f a démonstration System i n t h e c l i n i c a l s e t t i n g w i l l be e l u c i d a t e d .

1. INTRODUCTION

The World H e a l t h O r g a n i s a t i o n d e f i n e s r e h a b i l i t a t i o n as t h e m u l t i d i s c i p l i n a r y p r o c e s s t o b r i n g , and t o keep, h a n d i c a p p e d p a t i e n t s i n a s t a t e o f h e a l t h i n which they can f u n c t i o n i n t h e most o p t i m a l way i n t h e i r s o c i a l and p h y s i c a l e n v i r o n m e n t . Hence, i n d e a l i n g w i t h s p i n a l c o r d i n j u r y p a t i e n t s , t h e réhabilitation p r o c e s s i s c a r r i e d o u t by a m u l t i d i s c i p l i n a r y team c o n s i s t i n g o f members from t h e médical the o c c u p a t i o n a l and p h y s i o - t h e r a p e u t i c a l , t h e s o c i a l and p s y c h o l o g i c a l , and the t e c h n i c a l d i s c i p l i n e s . Such a s e t up assumes t h a t a l l d a t a needed f o r t h e treatraent w i l l become a v a i l a b l e t o a i l team members, c o r r e c t l y and i n t i m e . I t t h u s r e q u i r e s an a c c u r a t e exchange o f u p - d a t e d i n f o r m a t i o n t o a i l team members.

Because t h e m u l t i d i s c i p l i n a r y a s p e c t i n r e h a b i l i t a t i o n m e d i c i n e i s such a b a s i c p o i n t . A d e t a i l e d s t u d y was s e t up w i t h t h e f o l l o w i n g g o a l s i n mind. • To a c h i e v e a b e t t e r u n d e r s t a n d i n g o f t h e dynamics o f the e n t i r e r e h a b i l i t a t i o n p r o c e s s . • To s t u d y t h e p o s s i b i l i t i e s o f d i r e c t d i g i t a l d a t a p r o c e s s i n g o f t h e t r e a t m e n t d a t a . • To p r o p o s e , i f w o r t h w h i l e , a d a t a a c q u i s i t i o n system i n o r d e r t o automate t h e d a t a p r o c e s s i n g w i t h i n t h e r e h a b i l i t a t i o n c e n t e r . T h i s p r o p o s a i s h o u l d i n c l u d e t h e conséquences i n r e l a t i o n t o t h e O r g a n i z a t i o n , t h e d a t a t r a n s f e r U n e s and t h e d i f f e r e n t t a s k s o f t h e p e r s o n n e l .

A t t h i s s t a g e t h e f i r s t two g o a l s have been r e a l i s e d , t h e l a s t one i s under s t u d y and a g r e a t d e a l o f t h e work has been done.

2. THE REHABILITATION PROCESS

The s t u d y o f t h e r e h a b i l i t a t i o n p r o c e s s o f s p i n a l c o r d l e s i o n s was e x e c u t e d a t t h e r e h a b i l i t a t i o n c e n t e r "De H o o g s t r a a t " a t Leersum, The N e t h e r l a n d s . The s t u d y s t a r t e d i n 1973 and c a n be d i v i d e d i n t o f i v e main phases, which a r e l i s t e d as f o l l o w s : • R e c o r d i n g o f t h e d a t a c o n c e r n i n g t h e t r e a t m e n t o f t h e p a t i e n t and h i s / h e r s t a t e o f h e a l t h . • D e s c r i p t i o n o f t h e s t a t e o f h e a l t h o f t h e p a t i e n t , and d a t a r e d u c t i o n • Development o f a p r o g n o s i s model o f t h e f u t u r e s t a t e o f h e a l t h o f t h e p a t i e n t . • A n a l y s i s o f t h e r e h a b i l i t a t i o n p r o c e s s dynamics on t h e b a s i s o f t h e t r e a t m e n t ( i n p u t ) and t h e s t a t e o f h e a l t h ( o u t p u t ) . • P r e d i c t i o n o f an o p t i m a l t r e a t m e n t p l a n . I n t h e p e r i o d o f 1973-1975 58 p a t i e n t s were o b s e r v e d on a weekly b a s i s ; 74 t r e a t m e n t v a r i a b l e s as w e l l as 148 s t a t e o f h e a l t h v a r i a b l e s were r e c o r d e d . The a v e r a g e p e r i o d o f t r e a t m e n t o f t h e p a t i e n t was a b o u t 43 weeks. The d a t a c o l l e c t i o n was c a r r i e d o u t by t h e t r e a t m e n t team members. The d a t a can be c l a s s i f i e d a s i n p u t and o u t p u t v a r i a b l e s c o n c e r n i n g t h e m e d i c a l a s p e c t s ( 84 and 39 v a r i a b l e s ) , t h e A c t i v i t i e s o f D a i l y L i v i n g (41 and 19), t h e p s y c h o - s o c i a l v a r i a b l e s (6 and 7) and t h e s u p p o r t o f a s s i s t i v e d e v i c e s and home a d a p t a t i o n s

(3 and 19), r e s p e c t i v e l y . The m e d i c a l v a r i a b l e s were r e l a t e d t o a s p e c t s l i k e u r i n a r y t r a c t i n f l a m m a t i o n , p r e s s u r e s o r e , and p a r a - o s t e o a r h t r o p a t h y ; t h e ADL v a r i a b l e s c o n c e r n e d a c t i v i t i e s l i k e d r e s s i n g , e a t i n g , p e r s o n a l h y g i e n e and w h e e l c h a i r r i d i n g ; t h e p s y c h o - s o c i a l v a r i a b l e s d e s c r i b e d t h e r e l a t i o n w i t h

t h e p a r t n e r , t h e f a m i l y and t h e team members, e m o t i o n a l s t r e s s , e t c . ; and f i n a l l y

goals

Figure 1: Blook diagram of the rehabilitation process of a patient with a spinal

cord lesion.

-

-o r t h -o s e s and h-ome a d a p t a t i -o n s . The i n p u t v a r i a b l e s were q u a n t i f i e d -on t h e b a s i s o f the d u r a t i o n o f t h e t r e a t m e n t and the k i n d o f t r e a t m e n t . To be a b l e t o compare the c o m p l e t e l y d i f f e r e n t o u t p u t v a r i a b l e s w i t h each o t h e r , a l l v a r i a b l e s were s c o r e d a t a s c a l e from 0 t o 5 i n the o r d e r o f a d e c r e a s i n g r e s t r i c t i o n t h a t a p a r t i c u l a r v a r i a b l e may have on t h e f u n c t i o n i n g o f t h e p a t i e n t , i . e . 0 i s i m p o s s i b l e , 1 i s v e r y r e s t r i c t i v e , 2 i s r e s t r i c t i v e , 3 i s

l i g h t l y r e s t r i c t i v e , 4 i s may become r e s t r i c t i v e and 5 i s n o t r e s t r i c t i v e a t a l l .

The d a t a r e d u c t i o n o f the o u t p u t v a r i a b l e s was a c h i e v e d by t h e f o l l o w i n g p r o c e d u r e . By u s i n g t h e knowledge and e x p e r i e n c e s o f t h e c l i n i c a l s t a f f a number o f v a r i a b l e s c o u l d be s k i p p e d because t h e y d i d n o t p r o v i d e a d d i t i o n a l i n f o r m a t i o n . F u r t h e r m o r e a number o f v a r i a b l e s d i d n o t change a t a l l , and so t h e y d i d n o t g i v e any dynamic i n f o r m a t i o n about t h e t r e a t m e n t p r o c e s s . From t h e 148 v a r i a b l e s o n l y 67 remained. As a n e x t s t e p a c o v a r i a n c e a n a l y s i s was c a r r i e d o u t , r e s u l t i n g i n t o 12 major i n d e p e n d e n t v a r i a b l e s , i . e . p r e s s u r e s o r e , m i c t u r i t i o n , p a r a o s t e o - a r t h o p a t h y , d y s r e g u l a t i o n , s p a s t i c i t y , communicat-i o n and p e r s o n a l h y g communicat-i e n e , wheel c h a communicat-i r a c t communicat-i v communicat-i t communicat-i e s , a b communicat-i l communicat-i t y t o s t a n d communicat-i n an u p r communicat-i g h t p o s t u r e , p e r i o d t h e p a t i e n t i s o u t o f h i s bed, a c c e p t a t i o n a t home, mood, and the r e l a t i o n w i t h the members o f t h e t r e a t m e n t team. In t h i s l i s t o f v a r i a b l e s the s u p p o r t v a r i a b l e s were l e f t o u t , because they t u r n e d out t o be j u s t a r e s u l t of the m e d i c a l , the ADL and t h e p s y c h o - s o c i a l v a r i a b l e s . The f i n a l r e s u l t was checked by means o f the D e l p h i r a n k i n g method. The v a r i a b l e s were j u d g e d by 20 s p e c i a l i s t s on the b a s i s of t h e f o l l o w i n g t h r e e a s p e c t s : D i r e c t danger f o r l i f e , c l i n i c a l t r e a t m e n t , and p o s t - c l i n i c a l f u n c t i o n . A l t h o u g h a r e d u c t i o n o f the t w e l v e v a r i a b l e s j u s t mentioned t o o n l y f o u r , b e i n g t h e m e d i c a l , ADL, p s y c h o - s o c i a l

and s u p p o r t v a r i a b l e s , was found t o be too rough f o r p r a c t i c a l u s e , F i g . 2 shows as an example what r e h a b i l i t a t i o n m e d i c i n e a c t u a l l y means: L i v i n g w i t h

Figure 2: The four major variables as a function of the treatment -period. y o u r h a n d i c a p (no i n c r e a s e o r d e c r e a s e i n t h e m e d i c a l s t a t e ) , l e a r n i n g t o use

what i s l e f t (a s t r o n g i n c r e a s e i n ADL p e r f o r m a n c e ) , becoming a p s y c h o - s o c i a l l y s t a b l e p e r s o n ( o n l y s m a l l v a r i a t i o n s i n the p s y c h o - s o c i a l s t a t e ) , and r e c e i v i n g t h e n e c e s s a r y s u p p o r t i n a s s i s t i v e d e v i c e s e t c ( i n c r e a s e i n t h e s u p p o r t v a r i a b l e ) . The f i g u r e a l s o shows v e r y c l e a r l y t h a t t h e s u p p o r t v a r i a b l e may be c o n s i d e r e d t o be a r e s u l t o f the p r o g r e s s o f t h e o t h e r v a r i a b l e s . M o s t l y a time a t l e a s t

10 weeks i s found, m a i n l y due t o the p r o c e d u r e s n e s e s s a r y t o o b t a i n f i n a n c i a l

s u p p o r t .

From F i g . 2 one l e a r n s t h a t t h e d i s c h a r g e o f the p a t i e n t from t h e r e h a b i l i t a t i o n

c e n t e r i s m a i n l y d e t e r m i n e d by t h e moment t h e home a d a p t a t i o n s and a s s i s t i v e d e v i c e s a r e a v a i l a b l e , s i n c e i n g e n e r a l most o f t h e o t h e r v a r i a b l e s have r e a c h e d a s t e a d y s t a t e v a l u e a t l e a s t 10 weeks e a r l i e r . I t was t h e r e f o r e

w o r t h w h i l e t o i n v e s t i g a t e whether i t i s p o s s i b l e t o p r e d i c t t h e m e d i c a l , ADL, p s y c h o - s o c i a l and s u p p o r t v a r i a b l e s o v e r a 10 weeks p e r i o d , so t h a t p o s s i b l e

s u p p l i e s can be a r r a n g e d i n t i m e . Two p r e d i c t i o n methods have been s t u d i e d , i . e . one b a s e d on a d e s c r i p t i o n o f t h e o u t p u t v a r i a b l e s by a Semi-Markov S e r i e s , and one on t h e s t a t e v a r i a b l e d e s c r i p t i o n .

The dynamics o f t h e Semi-Markov S e r i e s a r e g i v e n by: The p r o b a b i l i t y t h a t a v a r i a b l e makes a change from a c e r t a i n v a l u e i d i r e c t l y t o a n o t h e r v a l u e j a t any t i m e , and by t h e p r o b a b i l i t y t h a t t h e v a r i a b l e has a v a l u e i d u r i n g (n-1) weeks

b e f o r e a t r a n s i t i o n i s made t o t h e v a l u e j on week n. In u s i n g t h i s d e s c r i p t i o n i t i s assumed t h a t t h e f u t u r e changes o f a v a r i a b l e d e s c r i b i n g t h e s t a t e o f a p a t i e n t depend o n l y on t h e p r e s e n t s t a t e o f h e a l t h and on t h e amount o f t i m e t h e p a t i e n t has been i n i t . By c o u n t i n g t h e t r a n s i t i o n s i n t h e measured d a t a , t h e p r o b a b i l i t i e s can be e a s i l y f o u n d . Hence, g i v e n t h e s e p r o b a b i l i t i e s b a s e d on a p o p u l a t i o n o f p a t i e n t s , and g i v e n t h e d a t a p o i n t o v e r a c e r t a i n p e r i o d o f a p a r t i c u l a r p a t i e n t , a p r o g n o s i s can be made. F i g . 3 shows an example, where

Figure 3: The prognosis over a 10 weeks period of medical, ADL, psycho-social

and supply variables based on a 10 weeks record of a particular patient.

f o r - f o u r v a r i a b l e s b a s e d on t h e d a t a measured o v e r a 10 weeks p e r i o d a p r o g n o s i s

f o r t h e n e x t 10 weeks has been o b t a i n e d , whereas F i g . 4 shows a p r o g n o s i s o v e r 28 weeks based on the p r e v i o u s 10 o r 20 weeks, r e s p e c t i v e l y .

A more s o p h i s t i c a t e d method t o p r e d i c t t h e f u t u r e v a l u e o f t h e v a r i a b l e s i s based on a s t a t e v a r i a b l e d e s c r i p t i o n . S i n c e i n p u t and o u t p u t v a r i a b l e s have been measured the dynamics o f the e n t i r e r e h a b i l i t a t i o n p r o c e s s c a n be d e t e r m i n e d . Hence w i t h t h e model y ( k + l ) = A y ( k ) + B u ( k ) , where y ( k ) i s t h e s t a t e v a r i a b l e as w e l l as t h e o u t p u t

380

-v e c t o r , u(k) i s the i n p u t t r e a t m e n t -v e c t o r , A i s the system m a t r i x and B i s the i n p u t m a t r i x , t h e s t a t e v a r i a b l e can be p r e d i c t e d g i v e n a c e r t a i n t r e a t m e n t p l a n .

Figure 4: Prognosis of an ADL variable over a 28 weeks period based on the data measured over the previous 10 or 20 weeks.

The m a t r i x A and B can d i r e c t l y be f o u n d from the i n p u t / o u t p u t d a t a measured. F i g . 5 g i v e s an example o f such a prédiction. Of c o u r s e , i f t h e t r e a t m e n t p l a n

i s a s t a n d a r d one, t h i s method can h e l p i n o v e r s e e i n g t h e conséquences o f a p a r t i c u l a r t r e a t m e n t f o r a g i v e n p a t i e n t . However, o f t e n i t i s t h e t r e a t m e n t p l a n i t s e l f t h a t s h o u l d be d e f i n e d . Thus t h e p r o b l e m s h o u l d t h e n be f o r m u l a t e d as an o p t i m i z a t i o n problem. G i v e n the r e h a b i l i t a t i o n p r o c e s s dynamics, and

5 U 3^ 2 1 a c t u a l ,,. 'v v a l u e p r e d i c t i o n S T A N D I N G 0 10 20 30 — t i m e [ w e e k s ] good score U 3 2 1 .1 I , " l ' w ' R E L A T I O N WITH A T T E N D A N T S 10 20 30

time [weeks]

Figure 5: Four predictions of state variables of a partioular patiënt on the basis of the initial state at the seoond week of treatment and a given treatment plan.

g i v e n t h e i n h e r e n t l i m i t a t i o n s i n t r e a t m e n t p o s s i b i l i t i e s , one has t o o p t i m i z e a c o s t f u n c t i o n c o n c e r n i n g the b e n e f i t s o f t h e t r e a t m e n t on t h e one s i d e and

t r e a t m e n t p l a n ; t h i s f i n a l s t e p i s p r e s e n t l y under s t u d y .

A l t h o u g h n o t a l l d e t a i l s o f t h e s t u d y can be g i v e n h e r e , a number o f i n t e r e s t i n g c o n c l u s i o n s has been r e a c h e d .

• The i n t r o d u c t i o n o f a c y b e r n e t i c m o d e l l i n g a p p r o a c h i n the r e h a b i l i t i o n c e n t e r y i e l d e d t h a t t h e team members became t o r e a l i z e t h a t a s y s t e m a t i c r e c o r d i n g by means o f c h e c k l i s t s a t r e g u l a r t i m e s i n c r e a s e d t h e i r u n d e r s t a n d i n g o f what the team was d o i n g a c t u a l l y .

Moreover i t opened t h e p o s s i b i l i t y t o e v a l u a t e the r e h a b i l i t a t i o n p r o c e s s . One a l s o became aware o f t h e e f f i c i e n c y o f u n i f o r m l y q u a n t i f i e d i n f o r m a t i o n exchange i n a m u l t i d i s c i p l i n a r y team.

• The 153 v a r i a b l e s o r i g i n a l l y r e c o r d e d i n o r d e r t o d e s c r i b e the p a t i e n t ' s s t a t e o f h e a l t h c o u l d be r e d u c e d t o o n l y 65 v a r i a b l e s w i t h o u t any l o s s o f i n f o r m a t i o n ; out o f t h e s e measurements t w e l v e s t a t e v a r i a b l e s c o u l d be d e t e r m i n e d f o r a s u f f i c i e n t d e s c r i p t i o n o f t h e p a t i e n t ' s s t a t e o f h e a l t h . • The m e d i c a l , ADL, and p s y c h o - s o c i a l v a r i a b l e s show t h a t a t l e a s t 10 weeks e a r l i e r a p a t i e n t c o u l d be d i s c h a r g e d f r o m t h e r e h a b i l i t a t i o n c e n t e r , i f i n t i m e the s u p p l y o f a s s i s t i v e d e v i c e s was s t a r t e d . The p r e d i c t i o n models were such p r o m i s i n g t h a t i t was b e l i e v e d t h a t on t h e b a s i s o f t h i s model t h e t r e a t m e n t p e r i o d c o u l d i n d e e d be d e c r e a s e d by t e n weeks, whereas t h e q u a l i t y o f c a r e w i l l r e m a i n t h e same.

• The d e s c r i p t i o n o f t h e r e h a b i l i t i o n p r o c e s s dynamics was f e l t t o be so a t t r a c t i v e and a c c u r a t e t h a t a p r o p o s a l o f an o p t i m a l t r e a t m e n t can be a w o r t h w h i l e c o n t r i b u t i o n as an i n p u t t o t h e t r e a t m e n t team, i n t h i s way a i d i n g i n making the f i n a l t r e a t m e n t p l a n d e c i s i o n .

• The g o a l s o f the t r e a t m e n t ( F i g . 1) seem t o be dependent on the r e s u l t s o b t a i n e d , t h a t means t h e g o a l s d u r i n g t h e e n t i r e r e h a b i l i t a t i o n p r o c e s s may change due t o new c i r c u m s t a n c e s . B e s i d e s t h a t , p a t i e n t and team members s h o u l d have e q u a l e x p e c t a t i o n s a b o u t what may be r e a c h e d . T h e r e f o r e a g o a l check l i s t has been d e v e l o p e d which has t o be f i l l e d o u t by p a t i e n t and team s e p a r a t e l y , once e v e r y t h r e e months. I n d i s c u s s i n g t h e d i f f e r e n c e s between t h e g o a l s o f t h e team members, i n c l u d i n g the p a t i e n t , one harmonizes the" j o i n t g o a l o f t h e t r e a t m e n t team. The r e s u l t s o f t h e i n t r o d u c t i o n o f t h e s e check l i s t were so s u c c e s s f u l t h a t p r e s e n t l y t h e method i s f u l l y a c c e p t e d as a s t a n d a r d p r o c e d u r e .

3 . THE DATA PROCESSING IN THE REHABILITATION CENTER: HUMAN FACTOR ASPECTS. The o v e r a l l i m p r e s s i o n o f t h e a p p r o a c h f o l l o w e d r a i s e d h i g h e x p e c t a t i o n s , so t h e i n t r o d u c t i o n o f an o n - l i n e d a t a p r o c e s s i n g system was c o n s i d e r e d . However, t h e i n t r o d u c t i o n o f s u c h a system means much more t h a n j u s t a k i n d o f a u t o m a t i o n o f d a t a h a n d l i n g . From t h e v i e w p o i n t o f man-machine communication i t y i e l d s a number of d i f f e r e n t a s p e c t s , among which t h e most i m p o r t a n t ones a r ei U:

• With t h e i n t r o d u c t i o n o f a d a t a p r o c e s s i n g system one s t a r t s t o c o n t r o l t h e i n f o r m a t i o n f l o w s a l o n g c a r e f u l l y p l a n n e d pathways, p r o b a b l y d i f f e r e n t from t h e e x i s t i n g ones. T h i s might l e a d t o s i t u a t i o n s where p e o p l e a r e n o t o r b a d l y i n f o r m e d , whereas o t h e r s a r e i n f o r m e d i n d i f f e r e n t ways.

• The i n f o r m a t i o n pathways a r e d i r e c t l y r e l a t e d t o t h e o r g a n i z a t i o n s t r u c t u r e o f a c l i n i c a l c e n t e r . A u t o m a t i o n t h u s may have i t s i n f l u e n c e on t h e e x i s t i n g o r g a n i z a t i o n s t r u c t u r e , t h a t i s the f o r m a l as w e l l as t h e i n f o r m a l s t r u c t u r e . • I f t h e i n f o r m a t i o n f l o w s a r e c h a n g i n g , and as a r e s u l t h e r e o f t h e o r g a n i z a t i o n

has t o be a d a p t e d , t a s k s o f d i f f e r e n t s t a f f members may be i n f l u e n c e d . Hence, t h e consequences o f s u c h an i n t r o d u c t i o n on t h e p e r s o n n e l ' s t a s k s and

3 8 2

-f u n c t i o n i n g s h o u l d be c a r e -f u l l y t a k e n under considération.

• The i n t r o d u c t i o n o f computer S y s t e m s i n a non-computer minded environment may l e a d t o a number o f i n t e r e s t i n g p r o b l e m s . F i r s t l y , t h e r e i s t h e p r o b l e m o f making t h e s t a f f familiär w i t h t h e new p o s s i b i l i t i e s o f t h e System, so t h a t n o t o l d methods a r e u s e d w i t h new equipment, b u t t h a t methods a n d equipment a r e u s e d i n an o p t i m a l way. Then, s e c o n d l y , one has t o t r a i n the f u l l y n a i v e s t a f f i n t h e use and opération o f t h e system.

m P r o t e c t i o n o f p r i v a c y i s a v e r y important i t e m i n d a t a p r o c e s s i n g i n h e a l t h

c a r e . O f t e n i t i s wrongly b e l i e v e d t h a t p r i v a c y p r o t e c t i o n w i l l dégrade when computers a r e u s e d .

The f i v e above mentioned items have been s t u d i e d e x t e n s i v e l y d u r i n g t h e l a s t few y e a r s , a l t h o u g h t h e e n t i r e p r o j e c t c e r t a i n l y w i l l r e q u e s t a n o t h e r c o u p l e o f y e a r s . To s t a r t w i t h , a d e t a i l e d s t u d y o f t h e i n f o r m a t i o n s t r u c t u r e a s w e l l as t h e O r g a n i z a t i o n s t r u c t u r e a t the r e h a b i l i t a t i o n c e n t e r has been c a r r i e d o u t , i n t h i s c o v e r i n g t h e f i r s t t h r e e i t e m s . P a r a l l e l h e r e t o a démonstration o f t h e p o s s i b i l i t i e s o f an i n f o r m a t i o n p r o c e s s i n g system has been worked o u t i n o r d e r t o g e t some f e e l i n g about t h e l a s t two i t e m s . In d i s c u s s i n g t h e i n f o r m a t i o n and O r g a n i z a t i o n s t r u c t u r e t h e emphasis o f t h i s p a r a g r a p h w i l l be on t h e methodology o f t h e s t u d y , b e c a u s e t h e r e s u l t s a r e so c l o s e l y r e l a t e d t o t h e p a r t i c u l a r s e t t i n g a t t h e r e h a b i l i t a t i o n c e n t e r t h a t i n u n d e r s t a n d i n g t h e r e s u l t s a d e t a i l e d d e s c r i p t i o n o f t h e r e h a b i l i t a t i o n c e n t e r i s r e q u i r e d . C o n s i d e r i n g o n l y t h e p r o c e s s i n g o f t h e t r e a t m e n t d a t a o f t h e s p i n a l c o r d lésion p a t i e n t s i t i s n e c e s s a r y t o o v e r s e e t h e i n f l u e n c e o f modem i n f o r m a t i o n Systems on t h e i n f o r m a t i o n exchange and t h e O r g a n i z a t i o n . T h i s has been a c h i e v e d by

a p p l y i n g t h e ISAC method d e v e l o p e d by t h e Department o f I n f o r m a t i o n P r o c e s s i n g and Computer S c i e n c e o f t h e R o y a l I n s t i t u t e o f T e c h n o l o g y and t h e U n i v e r s i t y o f S t o c k h o l m , Sweden. The ISAC method s t a n d s f o r t h e I n f o r m a t i o n System Work and A n a l y s i s o f Changes. Due t o t h e , i n gênerai, h i g h c o m p l e x i t y o f t h e problems

s t u d i e d , t h e method d i s t i n g u i s h e s f i v e i n t e r a c t i v e p h a s e s . Each p h a s e , i n d i v i d u a l l y , l e a d s t o a s e t o f d o c u m e n t a t i o n , i . e . g r a p h s and d e s c r i p t i o n s . S t a r t i n g w i t h a

g l o b a l r e v i e w g r a p h o f t h e e n t i r e system one zooms i n t o a s e t o f g r a p h s o f t h e différent Subsystems. The f i v e i n t e r a c t i v e p h a s e s a r e : (1) Change A n a l y s i s ;

(2) A c t i v i t i y S t u d i e s ; (3) I n f o r m a t i o n A n a l y s i s ; (4) Data System D e s i g n ; and (5) Equipment A d a p t a t i o n .

The Change A n a l y s i s d e a l s w i t h t h e s t u d y o f p o s s i b l e changes (improvements) i n the a c t i v i t i e s o f t h e O r g a n i z a t i o n . These p o s s i b l e changes a r e b a s e d on t h e i n s i g h t g a i n e d about t h e O r g a n i z a t i o n , t h e o b s e r v e d problems and t h e p r o b l e m s t o be

e x p e c t e d i n f u t u r e .

The major p u r p o s e o f t h e Activîty S t u d i e s i s t h e définition o f t h e i n f o r m a t i o n subSystems, t h a t i s t h e system o f i n f o r m a t i o n p r o c e s s i n g and n o t t h e a c t u a l

t r e a t m e n t p r o c e s s . The r e s u l t s c o n s i s t o f a g r a p h as w e l l as a l i s t o f i n f o r m a t i o n Subsystems, a c o s t - b e n e f i t a n a l y s i s , t h e r e q u i r e d f i n a n c i a l means, a t i m e s c h e d u l e and a définition o f t h e i n t e r a c t i o n between t h e subSystems. T h i s phase w i l l r e s u i t i n a f i n a l décision t o c o n t i n u e o r t o s t o p t h e p r o j e c t .

The I n f o r m a t i o n A n a l y s i s phase d e a l s w i t h a d e t a i l e d d e s c r i p t i o n o f a i l i n f o r m a t i o n subSystems. T h r e e s u c c e e d i n g a n a l y s e s have t o be e x e c u t e d . D u r i n g t h e P r e c e d e n c e A n a l y s i s one t r i e s , s t a r t i n g from t h e Output i n f o r m a t i o n s e t s , t o f i n d which p r e c e d i n g i n f o r m a t i o n s e t s a r e t h e r o o t s o f t h e O u t p u t s . T h i s p r o c e s s i s c o n t i n u e d u n t i l t h e i n p u t i n f o r m a t i o n s e t s o f t h e subsystem have been r e a c h e d . The n e x t

s t e p i s t h e Component A n a l y s i s , d u r i n g which an e x a c t d e s c r i p t i o n o f t h e i n f o r m a t i o n s e t s i s o b t a i n e d . F i n a l l y , a P r o c e s s A n a l y s i s i s e x e c u t e d , t h a t i s a d e s c r i p t i o n i s g i v a n i n which ways and under which r e s t r i c t i o n s t h e i n f o r m a t i o n s e t s a r e t r a n s f o r m e d i n t o o t h e r i n f o r m a t i o n s e t s .

The l a s t two p h a s e s , Data System D e s i g n and Equipment A d a p t a t i o n r e f e r t o t h e r e a l i z a t i o n o f t h e i n f o r m a t i o n p r o c e s s i n g S y s t e m . The DSD d e a l s w i t h t h e d e s i g n o f t h e System, t h a t i s t h e d e s i g n o f t h e s t r u c t u r e o f t h e system, t h e d e s i g n o f t h e r e q u i r e d components and t h e d a t a p r o c e s s i n g method - a u t o m a t i c o r manual o r a c o m b i n a t i o n ; b a t c h o r o n - l i n e o r i n - l i n e e t c -. Düring t h i s phase t h e component and p r o c e s s d e s c r i p t i o n s a r e t r a n s l a t e d i n t o d a t a s t r u c t u r e s and p r o c é d u r e s . The f i n a l s t e p o f t h e ISAC method i s t h e a d a p t a t i o n o f t h e d a t a system d e s i g n t o the computer c o n f i g u r a t i o n c h o s e n .

ACTIVITY GRAPH _{INFORMATION PRECEDENCE GRAPH}

fCHARGED PATIENT

Fi.gu.re 6: The aotivity graph and information graph of the treatment process of spinal cord injuries.

384

-In the manner as d e s c r i b e d b e f o r e the e n t i r e i n f o r m a t i o n a n d o r g a n i z a t i o n s t r u c t u r e o f the r e h a b i l i t a t i o n c e n t e r can be d e p i c t e d by g r a p h s . As an e x a m p l e t h e a c t i v i t y graph and the i n f o r a m t i o n precedence graph f o r the t r e a t m e n t p r o c e s s o f p a t i e n t s w i t h a s p i n a l c o r d l e s i o n w i l l be d i s c u s s e d now.

The a c t i v i t y graph: B e f o r e one i s a b l e t o s t a r t the treatment o f a p a t i e n t a n e x a m i n a t i o n has been e x e c u t e d , moreover d a t a from the h o s p i t a l have b e e n c o l l e c t e d , hence at the b e g i n n i n g of the t r e a t m e n t a c e r t a i n amount of d a t a i s a v a i l a b l e . With t h i s i n f o r m a t i o n , the p a t i e n t and the n e c e s s a r y means, one can s t a r t the t r e a t m e n t . D u r i n g t h i s p r o c e s s a d d i t i o n a l d a t a w i l l b e c o l l e c t e d on the b a s i s of w h i c h the treatment can be e v a l u a t e d , so t h a t a d e c i s i o n can be made whether the p a t i e n t w i l l be d i s c h a r g e d or whether the t r e a t m e n t has t o be c o n t i n u e d .

The i n f o r m a t i o n precedence graph: In o r d e r to b e a b l e t o e x e c u t e the r e h a b i l i t a t i o n p r o c e s s a p e r f e c t i n f o r m a t i o n exchange between the members of the t r e a t m e n t team i s n e c e s s a r y . The i n f o r m a t i o n precedence graph i l l u s t r a t e s how an i n f o r m a t i o n s e t

i s r e c o n s t r u c t e d from p r e c e d i n g s e t s . F o r i n s t a n c e , i n o r d e r to s u p p l y a p a r t i c u l a r a s s i s t i v e d e v i c e one needs a p r o g n o s i s as w e l l as d a t a about the t r e a t m e n t p r o c e s s i t s e l f . The t r e a t m e n t d a t a i s c o n s t r u c t e d from the r e h a b i l i t a t i o n r e c o r d s , treatment i n s t r u c t i o n s , and c o l l e c t e d t r e a t m e n t d a t a . A summary i n w h i c h a l s o the p r o g n o s i s i s i n c l u d e d w i l l r e s u l t i n the updated r e h a b i l i t a t i o n r e c o r d s s e t . The i n s t r u c t i o n s f o r the d i f f e r e n t d i s c i p l i n e s can be d e r i v e d a f t e r the t r e a t m e n t g o a l s as w e l l as the treatment p l a n a r e known. Combined w i t h the i n f o r m a t i o n g a t h e r e d d u r i n g the f i r s t e x a m i n a t i o n as w e l l as the r e h a b i l i t a t i o n d a t a r e c o r d e d one o b t a i n s updated r e h a b i l i t a t i o n r e c o r d . F i n a l l y the s e t d i s c h a r g e i n f o r a m t i o n i s o b t a i n e d by a f u r t h e r e v a l u a t i o n o f the t r e a t m e n t d a t a .

A l t h o u g h the method d i s c u s s e d i s a time consuming p r o c e d u r e , because the t r e a t m e n t of the b o d i l y handicapped p a t i e n t i s such a complex and m u l t i d i s c i p l i n a r y p r o c e s s , the method c e r t a i n l y l e a d s t o a v e r y c l e a r i n s i g h t i n the s t r u c t u r e o f i n f o r m a t i o n and o r g a n i z a t i o n o f the c l i n i c . There i s almost no need t o e l u c i d a t e how i m p o r t a n t the r e s u l t s a r e w i t h r e f e r e n c e t o the f i n a l d e s i g n of human t a s k s , t o t h e

i n t r o d u c t i o n of an i n f o r m a t i o n p r o c e s s i n g system and t o t h e man-computer communication.

4. A PRELIMINARY MAN-COMPUTER-COMMUNICATION STUDY.

In o r d e r t o g e t more i n s i g h t i n t h e d i r e c t problems r e l a t e d t o t h e i n t r o d u c t i o n o f a computer system i n t h i s p a r t i c u l a r s i t u a t i o n , i t was d e c i d e d i n an e a r l y s t a g e t o s e t up a s i m u l a t i o n so t h a t p r a c t i c a l e x p e r i e n c e s i n a c l i n i c a l s e t t i n g c o u l d be g a i n e d . The most i m p o r t a n t r e a s o n s can be s t a t e d as f o l l o w s :

® I t was n e c e s s a r y i n an e a r l y s t a g e t o t e s t t h e d i a l o g u e d e s i g n , when w o r k i n g w i t h n a i v e u s e r s . • In l i t e r a t u r e i t i s emphasized t h a t i t i s v e r y i m p o r t a n t t h a t from t h e b e g i n n i n g t h e f i n a l u s e r s o f a system a r e i n v o l v e d i n t h e p r o j e c t . T h e i r feedback i s v e r y e s s e n t i a l , and t h e i r i n v o l v e m e n t i s c r u c i a l f o r a s u c c e s s f u l i n t r o d u c t i o n o f a computer system.

F o r a d i a l o g u e between man and computer s e v e r a l p o s s i b i l i t i e s e x i s t . S e v e r a l a u t h o r s d i s t i n g u i s h between a number o f d i f f e r e n t t e c h n i q u e s , r a n g i n g from f u l l y Computer i n i t i a t e d t o f u l l y O p e r a t o r - i n i t i a t e d 5 , 6 . or as se en from t h e o p e r a t o r r a n g i n g

from p a s s i v e t o a c t i v e d i a l o g u e s . F o r c h o o s i n g a p a r t i c u l a r k i n d o f d i a l o g u e t h e f o l l o w i n g c r i t e r i a a r e g i v e n : L e v e l and k i n d o f e d u c a t i o n o f t h e u s e r s o f a system; f r e q u e n c y t h e system i s used and k i n d o f computer a p p l i c a t i o n . F o r t h e c a s e o f t h e r e h a b i l i t a t i o n c e n t e r t h e s o - c a l l e d m e n u - s e l e c t i o n seemed

t o be an a p p r o p r i a t e c h o i c e . T h i s i s a p a s s i v e d i a l o g u e , where the u s e r has t o choose from l i s t s o f p o s s i b i l i t i e s p r e s e n t e d on the s c r e e n , i n o r d e r t o

f i n d the i n f o r m a t i o n r e q u e s t e d . T h i s m e n u - s e l e c t i o n i s an e a s y - t o - l e a r n d i a l o g u e s t y l e , b u t i t w i l l become b o r i n g f o r e x p e r i e n c e d u s e r s . Hence, f o r them p o s s i b i l -i t -i e s t o r e a c h t h e -i n f o r m a t -i o n , b y p a s s e s , have t o be p r o v -i d e d . Important o t h e r a s p e c t s i n the d e s i g n o f a d i a l o g u e f o r n a i v e u s e r s a r e : The system has t o be f o o l p r o o f , t h e q u a n t i t y o f i n p u t - d a t a s h o u l d be m i n i m i s e d , and t h e a p p l i c a t i o n o f a b b r e v i a t i o n s f o r d a t a i n p u t i s v e r y désirable, i f and o n l y i f , s t r i c t r u l e s a r e g i v e n t o which an a b b r e v i a t i o n i s formed Important ergonomie a s p e c t s a r e : The f a c t whether the i n f o r m a t i o n i s p r e s e n t e d l i n e by l i n e o r page by page, t h e use o f c a p i t a l ? and lower c a s e l e t t e r s ; the use o f s p e c i a l f e a t u r e s such as r e v e r s e v i d e o ; t h e use o f s p e c i a l - p u r p o s e t e r m i n a i s as o f t e n i s a d v i s e d ->'^; t h e q u a n t i t y o f i n f o r m a t i o n p e r page and the s t a n d a r d i z a t i o n o f the l a y - o u t on the p a g e s .

Based on the l i t e r a t u r e r e v i e w e d a s m a l l démonstration t e s t system has been r e a l i s e d on t h e u n i v e r s i t y ' s IBM 370 system w i t h a B e e b i v e - t e r m i n a l . T h i s t e r m i n a l had a

r e v e r s e v i d e o f a c i l i t y , o n l y one programmable f u n c t i o n key c o u l d be a p p l i e d The d i a l o g u e was d e v e l o p e d i n CPS, an i n t e r a c t i v e s u b s e t o f P L / I . The s t r u c t u r e o f t h e t e s t system i s shown i n F i g . 7. E v e r y b l o c k i n t h i s f i g u r e r e p r e s e n t s a page on the s c r e e n . On the f i r s t page the u s e r has t o i d e n t i f y him- o r h e r s e l f

F I R S T P A G E N E W L Y REC0RD-E D P A T I REC0RD-E N T

bypass

L

3 ™ £

bypass

3 8 6

-( P r i v a c y p r o t e c t i o n ) , t h e n one h a s t o s t a t e w h e t h e r one wants t o f o l l o w t h e

b v p a s s o r t h e menu. The menu c o n s i s t s o f : A l i s t o f p a t i e n t s , a l i s t o f f i l e s

o f e v e r y p a t i e n t , and a l i s t o f c h a p t e r s o f a p a r t i c u l a r f i l e . As an example

t h e g o a l check l i s t as m e n t i o n e d i n p a r a g r a p h 2 was worked o u t . Then, f i n a l l y

one h a d t o i n d i c a t e w h e t h e r one wanted t o f i l l o u t o r j u s t t o o b s e r v e t h e g o a l

c h e c k l i s t . The r e a s o n f o r d i s t i n g u i s h i n g two v e r s i o n s o f t h e g o a l c h e c k l i s t

i n t h e menu i s t h e f a c t t h e o b s e r v a t i o n o f t h e l i s t as shown i n F i g . 8 i s

easy t o i n t e r p r e t , whereas d u r i n g t h e f i l l o u t phase t h e p o s i t i o n i n g o f an X,

P o r T ( F i g . 8) by a c u r s o r t a k e s more t i m e and l e a d s t o more m i s t a k e s t h a n

j u s t t y p i n g i n a code from

1 t h r o u g h 5. Hence i n t h e o b s e r v e v e r s i o n t h e d a t a

a r e p r i n t e d i n c o l u m n s , and i n t h e f i l l o u t v e r s i o n t h e d a t a t y p e d i n c o d e .

B e s i d e s t h i s menu sélection method t h e system was s e t up i n s u c h a way t h a t v i a

t h e b y p a s s one a l s o c o u l d r e a c h t h e d a t a . I n t h i s i n t e r a c t i v e p r o g r a m one

c o u l d use a b b r e v i a t i o n s .

As m e n t i o n e d b e f o r e ; an i m p o r t a n t a s p e c t i n c o m p u t e r i z i n g t h e d a t a h a n d l i n g

i s p r i v a c y p r o t e c t i o n . R u l e s have t o be f o r m u l a t e d a s answers t o t h e q u e s t i o n s :

• Who i s a l l o w e d t o e n t e r a new p a t i e n t i n t h e d a t a b a s e , and who i s a l l o w e d

t o e n t e r a p a r t i c u l a r d a t a a b o u t a p a t i e n t ? How c a n one p r e v e n t t h a t p e o p l e

who a r e n o t a u t h o r i s e d t o do s o , w i l l change d a t a ?

• Who i s a l l o w e d t o r e a d t h e i n f o r m a t i o n , and how c a n we p r e v e n t p o s s i b l e

m i s u s e o f t h e System?

COAL CHECK L I S T _{DATE : 10- -15} PATIENT NAME STATUS m ADMISSION DATE ANAKNESIS BAKKER 0015 05-29-1980 TETRAPLEGIC NO UNKT10WN Ï E S REALIZED NOT A P P L I C A B L E QUESTIONS PATIENT TERK BOTH ADL _{1 2} 3 k 5

13 INDEPEND. IN/OUT OF BED ^k INDEPEND. FROM FL00R TO CHAIR 15 P I C K UP ARMREST FROM GROUND 16 GET UP FROM GROUND

17 USE T O I L E T WITHOUT HELP 18 USE TOILET WITH HELP

19 INDEPEND. DRESSING UPPER BODY 20 INDEPEND. UNDRESSING UPPER BODY 21 INDEPEND. DRESSING LOWER BODY 22 INDEPEND. UNDRESSING LOWER BODY 23 INDEPEND. WASHING UPPER BODY

2k INDEPEND. WASHING LOWER BODY

X . . X P . . P P . T P P . P T . P . P X . . X 13 114 15 16 1? 18 19 20 21 22 23 2k CONTINUE? l i n e i n r e v e r s e v i d e o

The f i r s t question implies that the system must recognize who i s on the s t a f f

of the center, both questions imply that the system must i d e n t i f y who i s who.

A safe method i s to make use of pass-words, a f r e q u e n t l y used method i n banking

D p e r a t i o n s .

21 subjects, equally d i s t r i b u t e d over the d i f f e r e n t d i s c i p l i n e s of the c l i n i c a l

s t a f f tested the system v o l u n t a r i l y . Their opinions about the system were c o l l e c t e d

by watching the subjects during the t r a i n i n g sessions, and by questioning them

by means of check l i s t s . Two c l a s s e s of opinions were gathered, i . e . one c l a s s

about the use of computers i n a r e h a b i l i t a t i o n center i n general, and another

about the use of t h i s p a r t i c u l a r system. The f i r s t check l i s t had to be f i l l e d

out before the t r a i n i n g session, the second one at the end of the t e s t p e r i o d .

The i n q u i r i e s showed t h a t the group, although representative with reference to the

d i s t r i b u t i o n over the d i s c i p l i n e s , was c e r t a i n l y not representative with reference

to t h e i r a t t i t u d e to computers. The majority judged p o s i t i v e l y about automation

of the data handling, whereas i t was known that a large group was more r e l u c t a n t .

The r e s u l t s can be summarized as follows:

• Speed of data transport should be i n the order of

9600 baud; the system response

time should c e r t a i n l y be i n the order of a f r a c t i o n of a second and i n the

case i t takes longer i t should be i n d i c a t e d by a message l i k e "Your data are

now being processed"; the r e l i a b i l i t y of the system should be high, and an

i n d i c a t i o n whether the system works or not i s e s s e n t i a l f o r the use with

naive subjects.

# The idea of working with pass-words appeared to be working w e l l , although

f l e x i b i l i t y due to s h i f t i n g s t a f f members i s very important; menu s e l e c t i o n

i s a very a t t r a c t i v e method f o r infrequent users and beginners, or as reference

p o s s i b i l i t y , good bypass p o s s i b i l i t i e s are c e r t a i n l y required f o r the

experienced user; although only one s p e c i a l function key was a v a i l a b l e , the

a p p l i c a t i o n of more f u n c t i o n keys such as, a Begin-, Stop-, C o r r e c t i o n - ,

Next Page- and a Break- key seems to be valuable; the dialogue should be

user-f r i e n d l y .

5. ACKNOWLEDGEMENT

The authors would l i k e to acknowledge a l l members of the treatment team f o r

s p i n a l cord lésions of the R e h a b i l i t a t i o n Center "De Hoogstraat" f o r t h e i r

very enthousiastic assistence i n c o l l e c t i n g the necessary data, and t h e i r

s t i m u l a t i v e c o n t r i b u t i o n s i n the form of workshops and d i s c u s s i o n s . Also

the 58 p a t i e n t s , who were subject of t h i s study on the one side , and data

c o l l e c t o r s on the other, should be acknowledged. Without t h e i r p o s i t i v e a t t i t u d e

t h i s study could not have been done.

6 . LITERATURE

1. Hoogendoorn, R.; H. Bakker; H.G. Stassen; B.L.J. van Veen:

Cybernetic Mathematical Model of the Treatment of P a t i e n t s with I n j u r i e s

of the Spinal Cord. In: Stassen, H.G. Progress Report Jan. 1973 u n t i l July

1976 of the MMS-Group, DUT, 1977, pp. 224-242, WHTD 95.

2. Hoogendoorn, R.:

Modelling of the r e h a b i l i t a t i o n process of cord lésions (In Dutch).

In: Proc. VMBI-MIM, Rotterdam, 1978, pp. 275-280

3 8 8

-Hoogendoorn, R. :

The e f f i c i e n c y o f the M u l t i d i s c i p l i n a r y Treatment o f B o d i l y Handicapped (In D u t c h ) , DUT, 1979, 76+159+58 p., N-167/R-546.

Lundeberg, M; G. G o l d k u h l ; A. N i l s s o n :

I n f o r m a t i o n Systems Development - A S y s t e m a t i c Approach. R o y a l I n s t , of Techn. / U n i v . o f Stockholm, 1 9 8 0 . M a r t i n , J . : D e s i g n o f man-computer d i a l o g u e s . P r e n t i c e H a l l , Englewood C l i f f s , N . J ., 1973 , 559 p . H e b d i t c h , D.: D e s i g n o f d i a l o g u e s f o r i n t e r a c t i v e commercial a p p l i c a t i o n s , I n : P r o c . I n f o t e c h . C o n f . on man-computer communication, Amsterdam, 1978, 22 p .

Rouse, S.H.; W.B. Rouse:

D e s i g n o f a model-based on l i n e management i n f o r m a t i o n system f o r i n t e r l i b r a r y l o a n n e t w o r k s . I n f o r m a t i o n p r o c e s s i n g and management, 1979, v o l . 15, pp. 109-122.

S t e w a r t , T.R.M.:

Communicating w i t h d i a l o g u e s . I n : P r o c . C o n f . on ergonomics and t h e d e s i g n o f computer d i a l o g u e s . U n i v e r s i t y o f T e c h n o l o g y , Loughborough, 1979, pp. 77-95.

S c h i l l i n g , D.E.: C o p i n g w i t h the c a s u a l u s e r . I n : P r o c . I n f o t e c h c o n f . on man-computer communication. Amsterdam, 1978, 9 p .

S t a s s e n , H.G.; A. v a n L u n t e r e n ; R. Hoogendoorn; G.J. v a n d e r K o l k ; P. B a l k ; G. M o r s i n k ; J.C. Schuurman:

A computer model as an a i d i n t h e t r e a t m e n t o f p a t i e n t s w i t h i n j u r i e s o f t h e s p i n a l c o r d . I n : P r o c . I n t . C o n f . on C y b e r n e t i c s a n d S o c i e t y , IEEE, Cambridge, Mass., 1981, 385-390.