Neuropsychologia,

1977,

Vol. 15,pp. 845 to 848. PcrgamonPress.Printedin England.

NOTE REACTION

TIME IN PATIENTS

WITH CEREBRAL

HEMIPARESIS

RYUICHI NAKAMURA and REIJI TANIGUCHI Tokyo Metropolitan Institute for Neurosciences, Department of Rehabilitation, 2-6 Musashidai, Fuchu-city, Tokyo, Japan

(Received I March 1977)

Abstract-RT, PMT and MT of finger extensor muscles on a finger lifting task were measured in 12 left and 10 right hemiparetic patients due to cerebra-vascular accidents, and 10 healthy subjects. Compared with controls, patients with left hemiparesis showed a slower PMT in both hands, but those with right hemiparesis did not. The delay of MT was observed in the affected hand of both hemiparesis. There was also a positive correlation of MTs between the affected and non-affected hands. The overall slowing of RT was related to slowing of PMT and delay of MT in patients with hemiparesis. RECENT studies reported that the simple reaction time (RT) would be increased by lesions of either hemisphere, but more so by those of the right or non-dominant hemisphere [l, 21. Mechanical responses were used to measure RT in these experiments. The RT could be divided into the premotor time (PMT) measured from the stimulus to the beginning of the EMG activity of prime mover muscles, and the motor time (MT) elapsed between the EMG onset and the mechanical response [3]. Pyramidotomy in monkeys induced a long-lasting delay of MT in the performance of the finger grip, but only a transient slowing of PMT [4]. JUNG and DIETZ [5] reported that patients with pyramidal paresis showed the slowing of PMT as well in the affected side. Thus, there remain still questions how PMT and MT are influenced by the cerebral involvements including pyramidal tract, and whether there is any difference between the left and right hemiparetic patients. In this study we measured RT, PMT and MT of patients with hemiparesis due to cerebra-vascular accidents, and tried to analyse what components induced mainly a slowing of RT.

METHOD Twenty-two patients with hemiparesis were selected from the rehabilitation ward of Juntendo University Hospital and Tokyo Metropolitan Fuchu Hospital, and 10 healthy subjects as a control. They were all right-handed. Although there were some residual impairments of motor function such as slight spasticity and muscular weakness measured by a grip test, all patients could move separately each finger of the affected hand and pick up a small piece of beads with the affected hand (Table 1). Table 1. Summary of subjects Number Age After onset Grip power

-

male; female mean ; range (yr.) mean; range (mo.) mean; range (kg) left-hand right-hand

Control 4; 6 65.1; 43-17 -

L-hemiparesis 10; 2 66.4 ; 49-80 145; l-46

R-hemiparesis 8; 2 57.8 ; 33-69 22.1; 1-45

-

8.9; 4.8-15.6 17.5 ; 74-28.6

16.4; 5%)-24.6 14.0; 8.0-25.2

*Grip power was measured with transducer (HG/50 kg, cp = 50 mm, Shinkoh). The subject was seated comfortably on a chair in front of a desk on which the forearms were rested. A small metal knob was taped on the ventral surface of the middle finger and was made contact with the metal plate on which the hand rested at the start of the trial. The metal knob and plate formed a switch, which opened when the finger lifted from the plate, thus signalling the precise instance of “off time”. EMG was taken from finger extensor muscles with surface electrodes. Both the off signal and EMG activity were recorded on a memoscope equipped in an average computer (ATAC 501-10, Nihonkohden). Figure 1 shows the experimental schema and a display on the memoscope in which the time, tO--tz, is RT; t,-f, is PMT and t,-t, is MT. 845

846

NOTE

1.. -- - ) ;I

t0

FIG. 1. Experimental

I i +,

~ 2oopv - IcGec.

schema and a display on the memoscope: r,; onset of stimulus; t,, onset of EMG; I,, off signal of mechanical response.

The subject was first given a warning verbal signal, “Yoi (ready)“, and 2-4 set afterwards a peep sound (1000 Hz, 100 dB, 50 msec duration). The subject was instructed to respond as quickly as possible to the peep sound with extension of middle finger, thus lifting the metal knob from the plate. Before experimental run several trials were performed to make the subject acquainted thoroughly with the procedure. In each experiment more than 10 trials were repeated in each hand at the interval of 10-20 sec. The half of the control subjects performed the test firstly with the left hand and the other half with the right. The patients started their trials with the non-affected hand and then with the affected. Although the subject was requested to relax the arm as much as possible, there occasionally remained activities of some motor units. In these cases the trial was discarded. Samples of 10 trials in each side thus obtained were subjected to statistical analysis.

RESULTS The mean S.D. for RT, PMT and MT of the three groups are presented in Table 2. As compared with the control group (Table 3), the increase of RT was statistically significant in both hands of the left hemiparesis but it failed to attain statistical significance in the left hand of the right hemiparesis. The left hemiparesis showed significantly slower PMT in both hands but the right hemiparesis did not. Concerning MT, statistically significant delay was observed in the affected hand of both hemiparesis groups. Thus overall slowing of RT in the affected hand of the left hemiparesis was induced by the slowing of PMT and delay of MT, whereas that of the right hemiparesis was only due to the delay of MT, and the slowing of RT in the non-affected hand of the left hemiparesis was mainly caused by the slowing of PMT. Figure 2 demonstrates the scatter of PMT and MT for the hemiparesis groups. Figure 2a shows that the extent of slowing in PMT of the affected hand is nearly equivalent to that of the non-affected hand. The regression equation of the affected hand on the non-affected was y = 1.1 x -10.0 (rZ = 0.84) on the left hemiparesis group land y = 1.1 x -5.9 (r2 ==0.90) on the right hemiparesis. Lateralized cerebra! lesions in Table 2. Mean (S.D.) for RT, PMT and MT (msec) Left-hand: Right-hand:

--__ R T PMT M T R T PMT M T

Control --___ 160.7 (20.8) 118.2 (18.5) 42.5 ( 5.5) 168.1 (20.8) 124.5 (19.1) 43.6 ( 4.1)

L-hemiparesis 219.0 (60.7) 153.3 (45.7) 65.6 (20.4) 202.9 (44.1) 154.8 (39.7) 48.3 ( 9.0)

R-hemiparesis 182.2 (29.0) 139.5 (27.3) 42.6 ( 8.0) 204.8 (39.3) 143.4 (30.9) 61 .O (20.8)

847

NOTE

Table 3. Comparisons of RT, PMT and MT between the control group and hemiparesis groups by Student’s t-test or Welch’s method; t value (u”) Control

vs vs

* p < 0.05.

L-hemiparesis Left-hand Right-hand R-hemiparesis Left-hand Right-hand

RT

PMT

MT

2.9781 (14) 2.320* (16)

2.325* (15) 2.234* (16)

35991_ (12) 1.546 (16)

1.807 (18) 2.476* (13)

1.937 (18) 1.560 (18)

0.030 (18) 2.462* (12)

t p < 0.01.

our patients did not cause specially lateralized effect on PMT. Also there was a close correlation between the left and right MTs (Fig. 2b). The MT of the affected hand expected from that of the non-affected was demonstrated with the regression equation, y = 1.9 x -28.5 (r2 = 0.76) on the left hemiparesis group and y = 2.3 x -35.0 (r8 = 0.76) on the right. The delay of MT in the affected hand was coupled with that in the non-affected hand. The longer was MT of the non-affected hand in the hemiparesis, the larger the difference of MTs between the affected and non-affected hands. This phenomenon was similar both in the left and right hemiparesis.

150

250 200 Non-affected

hand,

msec

FIG. 2. The relation of PMT between the affected and non-affected hands (Fig. 2a), and that of MT (Fig. 2b). 0, left hemiparesis; 0, right hemiparesis.

DISCUSSION The results of this experiment confirm previous reports; unilateral cerebral lesions can produce a substantial increase in the simple RT of both hands, moreover, lesions of the right or non-dominant hemisphere cause greater impairment than those of the left or dominant hemisphere [l, 2, 61. By measuring PMT, this conclusion was clearly obtained. These data would be of some value to discuss the differentiation of hemispheric functions. It should be pointed out that significantly longer PMT in left hemiparesis is not related to impairments of motor output system or sensory system. This is deduced from the fact that the slowing of PMT was equally observed in both hands, and the auditory cue was binaurally given. Moreover, the slowing of RT was not restricted to a specific sensory modality, since right brain-damaged patients showed a significantly slower RT to visual and auditory stimulations [2,6j. It is conceivable that delays in processing of sensory stimulation for effective response is a main factor in the slowing of PMT. The right hemisphere has a dominant role in the sensory motor processing in the performance of simple RT task. BENTONand JOYNT[7] recognized the specific effect that patients with cerebral lesions restricted to one hemisphere and with no apparent motor deficits on the side contralateral to that of the lesion tend to show a more marked retardation in the reactions of the contralateral hand. From our results this specific effect is presumably related to the delay of MT in the affected hand. The important point of our findings is the positive correlation of MTs between the affected and nonaffected hands, although MT of the affected hand is longer than MT of the non-affected hand. This delay of MT in the non-affected hand is physiologically to be attributed to innervation from the ipsilateral or affected cerebral hemisphere through the non-crossed pyramidal tract [8], which participates in the control of force of movements [4, 91. If a patient with lateralized cerebral lesions has severe motor impairments

848

NOTE

and shows slower RT in the affected hand, the slowing of RT in the non-affected hand may be expected to result from the delay of MT.

REFERENCES HOWES, D. and BOLLER,F. Simple reaction time; evidence for focal impairment from lesions of the right hemisphere. Brain 98, 317-332, 1975. BENSON,D. F. and BARTON,M. I. Disturbance in constructional ability. Co&x 6, 19-46, 1970. BOTWINICK,J. and THOMPSON,L. W. Premotor and motor components of reaction time. J. exp. Psycho/. 71,9-15,1966. HEPP-REYMOND,M. C., TROUCHE,E. and WIESENDANGER, M. Effects of unilateral and bilateral pyramidotomy on a conditioned rapid precision grip in monkeys (Mucucafa~ciculari.~). E.xpl Brain Res. 21, 519-527, 1974. JUNG, R. and DIETZ, V. Verzijgerter Start der Willkiirbewegung bei PyramidenlSsionen des Menschen. Archs Psychiut.

Nervenkr.

221, 87-109,

1975.

DE RENZI, E. and FAGLIONI,P. The comparative efficiency of intelligence and vigilance tests indetecting hemisphericcerebraldamage. Cortex 1,410-433,1965. BENSON,A. L. and JOYNT,R. J. Reaction time in unilateral cerebral disease. Confin. Neural. 19,247-256, 1958. JANE, J. A., YASHON,D., BECKER,D. P., BEAITY, R. and SUGAR, 0. The effect of destruction of the corticospinal tract in the human cerebral peduncle upon motor function and involuntary movements. Report of 11 cases. J. Neurosurg. 29, 581-585, 1968. 9. EVARTS,E. V. Pyramidal tract activity associated with a conditioned hand movement in the monkey. J. Neurophysiol. 29, 1011-1027, 1966.

Deutschsprachige

Zusammenfassung:

Bei 12 Patienten

mit linksseitigen

seitigen Hemiparesen

und 19 Patic~~ten mit rechts-

und bei 1r? Gesunden

wurde durch eine Finger-

tiebe-Aufgabe die RT, PMT und MT der Fingerextensoren Verglichen

mit Kontrollpersonen

schen Patienten

eine verlsngerte

solche mit rechtsseitiger zijgerung der MT wurde

PMT in beiden Hqnden, wshrend

Hemiparese

tive Korrelation

der MT's zwischen H#nden.

iiBnden beider

Dariiber hinaus bestand

beobachtet.

bei den Hemiparetikern

dies nicht taten. Die Ver-

;jeweils an den betroffenen

Hemipareseformen nicht-betroffenen

gemessen.

zeigten die links-hemipareti-

den betroffenen

Die Gesamtverlangsamung

eine posiund den

der RT war

zuriickzufiihren auf die Verlangsamung

der PMT und die VerzBgerung

der MT.

Reaction time in patients with cerebral hemiparesis.

Neuropsychologia, 1977, Vol. 15,pp. 845 to 848. PcrgamonPress.Printedin England. NOTE REACTION TIME IN PATIENTS WITH CEREBRAL HEMIPARESIS RYUIC...
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