Intracarotid Sodium Amylobarbitone and Cerebral Dominance for Speech and Consciousness

Diseases, Queen Square, London S U M M A R Y Twenty-nine right handed patients were examined neurologically before and immediately after each of 62 unilateral ECTs to the dominant and non-dominant hemispheres. Most convulsions were followed by signs of transitory neurological dysfunction referable to the treated hemisphere. These signs included deep tendon reflex asymmetry, hemiparesis, tactile and visual inattention, and homonymous hemianopia. After treatment to the right hemisphere some patients had left visuospatial neglect, while all patients who had dominant hemisphere ECT were transiently dysphasic. All neurological abnormalities tested resolved within 20 minutes of treatment.We have previously reported results of separate electrophysiological investigations in which the EEG, flash evoked potential (VEP), and somatosensory evoked potential (SEP) were monitored during the half hour period after unilateral ECT (Kriss et al., 1975(Kriss et al., , 1977a(Kriss et al., ,b, 1978. Briefly, these studies showed that during the induced seizure the EEG had significantly larger epileptic slow wave activity on the treated side. In the immediate postictal period there was a clear asymmetry with the treated side producing significantly more delta and less alpha and beta activity than the contralateral side. These hemisphere differences, though becoming less marked, persisted beyond the end of the recording. Evoked potential studies showed differing results for the flash VEP and SEP. The VEP was markedly asymmetrical for 15 minutes after the shock with the major positive component (P140) being significantly smaller and later on the treated side. The SEP, however, showed no significant hemisphere differences. In view of these findings we decided to examine patients during the immediate post-ictal period to determine whether there was any clinical evidence of concomitant dysfunction, and to assess the severity and duration of any neurological asymmetries found.

Section: Discussionsupporting

confidence: 69%

Neurological asymmetries immediately after unilateral ECT.

Kriss¹,

Blumhardt²,

Halliday³

et al. 1978

“…This test has been used elsewhere to determine the degree of cerebral speech dominance in at least 308 normal speakers (Branch, Milner, and Rasmussen, 1964;Serafetinides, 1965;Milner, Branch, and Rasmussen, 1966;Rossi and Rosadini, 1967). While approximately 15% of left-handed (and ambidextrous) individuals show bilateral speech centres, such a result has been reported in only three right handers.…”

mentioning

confidence: 99%

Stuttering: an investigation into cerebral dominance for speech

Andrews

Quinn

Sorby

1972

SUMMARY Over the past decade research has suggested that stutterers have bilateral cerebral motor or auditory speech areas. Three typical adult stutterers showed normal unilateral left cerebral dominance for speech on the intracarotid sodium amylobarbitone (amytal) test, but one 'dysphatic' stutterer had bilateral cortical speech representation. The latter is a very rare finding in right handed individuals and presumably is a consequence of the head injury induced aphasia that preceded the onset of stuttering.Some 40o of children stutter, and while most subsequently remit, stuttering persists in about

“…[3][4][5] Further, left sided injections cause more prolonged EEG slowing and a greater decrease in cerebral blood flow in the injected hemisphere than right sided injections. 17 18 Whether hemispheric asymmetry in the intracarotid amobarbital test indicates true hemispheric dominance for arousal is controversial; proposed alternative explanations for a differential effect include increased cross flow to the opposite hemisphere following left versus right amobarbital injection 9 19 or differential hemispheric metabolic demands.…”

Section: Discussionmentioning

confidence: 98%

“…This hypothesis is based on two major lines of evidence: greater impairment of consciousness after acute left hemispheric stroke than after acute right hemispheric stroke 1 2 ; and greater sedation following left sided versus right sided intracarotid amobarbital injections given as part of the Wada test. [3][4][5] However, other reports have called this assessment into question. [6][7][8][9][10][11][12][13] Interpretation of these conflicting data is complicated by the fact that "consciousness" is a broad term encompassing many aspects of global cognitive function, including arousal, awareness, and attention.…”

mentioning

confidence: 99%

Lack of hemispheric dominance for consciousness in acute ischaemic stroke

Cucchiara

Kasner²,

Wolk³

et al. 2003

Background: Previous reports have suggested left hemispheric dominance for maintaining consciousness, although there is controversy over this claim. Objective: To compare early impairment of level of consciousness between patients with right and left hemispheric stroke. Methods: Data from 564 patients with ischaemic stroke enrolled in the placebo arm of a trial of a putative neuroprotectant were analysed. All patients had major hemispheric stroke with cortical dysfunction, visual field deficit, and limb weakness, with symptom onset within 12 hours of enrolment. Patients were prospectively evaluated on a predefined scale (1-6; 1 = fully awake, higher scores representing greater impairment) to measure level of consciousness at multiple time points over the initial 24 hours after presentation. The National Institutes of Health (NIH) stroke scale score at presentation and infarct volume at 30 days were determined. Results: Some degree of impairment in level of consciousness was observed in 409 of the 564 patients (73%). Median maximum sedation score was 2 for both right and left hemispheric stroke (p = 0.91). Mean sedation score over 24 hours was 1.5 for both right and left stroke (p = 0.75). There was no difference between level of consciousness scores in right and left stroke at any individual time point during the 24 hour monitoring period. No association between side and impairment in level of consciousness was seen after adjustment for stroke severity and infarct volume. Conclusions: In contrast to previous reports, there was no evidence for hemispheric dominance for consciousness in the setting of a major hemispheric stroke.