Neurophysiol Clin (1990) 20, S, 2 5 s - 2 7 s 25s © El sev i e r , P a r i s

Communications orales Oral communications

SESSION 9

Exploration 41ectrophysiologique du contr61e moteur Electrophysiological testing of motor control

O71

FUNCTIONAL COMPONENTS OF SLOW BRAIN POTENTIALS DURING VISUO-MANUAL TRACKING

A. Hufschmidt, T. Winker, C. H. LUcking Neurologische Un i ve rs i t g t sk l i n i k , D-7800 Freiburg, Hansastr. 9

Cort ical nega t i v i t y accompanying visuo-manual t racking is poorly loca l ized, spreading over almost the en t i re cortex. In the present work, i t was attempted to i d e n t i f y s ingle components o f the slow potent ia l by t h e i r r e l a t i on to indiv idual stages of sensorimotor processing. This was done by presentat ion o f two or three d i f f e r e n t tasks in a l te rnate t r i a l s (movements without v isual cont ro l , visual st imulat ion o f one/both hemi- f ie ]d(s) wi th /wi thout move- ment). As a resu l t , i t was found that e l e c t r i c a l cor re la tes of visual perception as well as of pure motor output con t r i - bute l i t t l e to the overa l l po tent ia l amplitude compared to the e f fec ts o f visuomotor in tegra t ion and di rected visual a t tent ion. For the l a t t e r two components, a r i gh t par ie ta l dominance was found. In a second ser ies of experiments, a d i f f e r e n t i a t i o n between these two stages was endeavoured.

072

/~D SCm~TQ~0F~ EVOKe3 POI~h~IALS IN P A ~ WI]~ YDCAL LESICNS OF

M.D., C I ~ P., I~SIATO M.T., ~ F., LAVARONI F., I~DI G.

a~d ROS~INI P.M.

Clin. ~urol. 11 University of Rcme '~c~ Ver~". Roma - Italy -

A comparative ~ of Nbto~ Ev~ed Po~tja]~ (B) and ~ ~ carried

otr~ nn 16 p~ i~" l t s witah spastic l ~ m r ~ i s (8) and N i s (8) due focal extr-amedu]Ja~ (9 h~mat~d d i ~ , 3 m~iz~,ms, 1 radiculm." haematc- rams) and ~¢cra,mdullm~ om'd ]~ions (3 hammtmms). ~ to m~netic brain ~ d m . t l a t i m ~ r e r e c ~ * l ~ from prc~mal N d i s t a l limb muscles and from

addcmir~ masclas. As MEP N m c ~ m i i t i e s ~ ~l~sidered ~ne fol l~r ing:

1) N N l d f~" I~P e l i c i g a t i o n ; 2) i N c r a v a t con~c~ion

time and 3) almm~t r e ~ p c ~ . Signif ican~ fhr~shold N t f w mdd0mJna]

and foot ~ elicJfatioo ~ foh~d in all patimts ~Jth ak~sc~lum~ cord

lesi~ws and in 7 out of 8 p~ci~-~s ~Jda cervical oc~dq~ior~. Pmolor~

scalp %o cervical c¢~d cc'r and scalp to lumb~- ccrd OCT ~re observed in 5

limbs and 8 icier limbs. /Ibsemt MI~s from lo~er limb ~ n g s were

found in 3 patients with lumbar lesions (6 limbs) and in 2 patients (4 limbsl

witin ce rv ica l l ~ i c r ~ . ~ i n t e r v a l s ~ delioJd-d~m%~', i n n ml

and a d d o m i n a l - p ~ muscle~ considered with ~ i d and our values

permitted fn localize the leve/ of altered pr~pas~ion in ~ment with the.

ne~x~olo~ical f'mdir~s (~C and ~I). SEPs to medi~, and per~i .erv~S

~e l~ss affected d~an M~s. Absent scalp responses to a fotmd in 2 patJe~Its

Al~on of tile cervical cord %0 scalp (L'r ~s encomte~ in 3 patients

(5 ~ ligl~), of hhe lumbar onrd to scalp (lYr in 7 patients (I0 lo~er

l imbs). ~hese t2pe o f netn~tinysiologic ~ a k l o ~ d a fa idnfu l ~ o f ~ e

level and of the ~ of spinal cc~d functional dsmm~e, i ~ out to be.

perticulz~ly t~efu l in the proNqc~ic eskimm~ as , ,~ll ~ f ~ the indica t ion

o f a poss ib le ~ c a l l~eaimant.