Amiram Carmon

Ear asymmetry in perception of emotional non-verbal stimuli ☆

Abstract Hemispheric asymmetry for perception of non-verbal emotional human voices was investigated in normal subjects by dichotic listening utilizing non-verbal responses. As in former experiments, a slight but significant left ear superiority was found. This finding suggests that mediation of these stimuli is done by the right hemisphere. The dominant role of the right hemisphere in this perceptual task is discussed in terms of an earlier development of this hemisphere.

Effect of Unilateral Brain Damage on Perception of Temporal Order

Summary The hypothesis that temporal perception is mediated by the dominant (left) hemisphere was tested by presenting sequential audiovisual stimuli to 47 patients suffering from unilateral lesions in the left or right hemisphere and to 42 control patients free from neurological disorders. The patients, presented with sequences of 3, 4 or 5 stimuli (3 colored lights and 2 sounds), chose any stimulus as a starting point, and identified the order of stimuli following it in the continuous sequence by pointing at the stimulus source. The results, analyzed by analysis of variance, showed that performance of patients suffering from left hemispheric lesion was significantly impaired as compared with that of the other patients. The data were interpreted as showing that in parallel with the specialization of the right hemisphere in spatial perception, the left hemisphere specializes in temporal perception.

Hand preference in sequential and spatial discrimination tasks.

Hand preference in sensorimotor discrimination tasks was tested on 80 right handed subjects in four experiments. One set of experiments compared the abilities of the two hands to perform sequential tasks. The other set compared spatial abilities of the two hands. Within each set one experiment involved unimanual performance, and the other bimanual performance. The results showed that subjects performed better with their right hand on the bimanual sequential task, and better with their left hand on the bimanual spatial task. No hand preference was found in the unimanual tasks. The results are interpreted as reflecting the differential sensorimotor dominance of the left and right hemispheres for sequential and spatial tasks respectively.

Sequenced motor performance in patients with unilateral cerebral lesions

Abstract Repetitive motor performance of groups of patients with right and with left hemispheric lesions and of control subjects was sequenced for locus and for pace in two separate experiments. The performance of the brain-damaged patients was inferior to that of the control subjects in the two tests. The side of the hemispheric lesions did not influence the performance of the patients when the locus was sequentially changed, but did affect it somewhat when the pace of tapping was constrained. When a fast pace of tapping was required, patients with lesions in the left hemisphere performed worse than patients with lesions in the right hemisphere. Under slow and moderate paces of tapping, a reverse trend occured. The results give only partial support to the possibility that motor behaviour is differentially controlled by the two hemispheres, but are in general agreement with prior experiments.

Responses of paranoid and nonparanoid schizophrenics in a dichotic listening task.

Differences in attentional processes between normals, paranoid schizophrenics, and non paranoid schizophrenics were studied by delivering dichotically presented digits for identification. Thirty paranoid schizophrenics (20 acute and 10 chronic), 30 non paranoid schizophrenics (20 acute and 10 chronic), and 20 normal controls were tested. The data were analyzed in terms of the overall level of correct identification of stimuli presented to the two ears, the number of shifts in report from one ear to the other, and the magnitude of ear differences in recall. The results showed that overall level of performance was higher for the normals than for the schizophrenics; the number of ear shifts was greater for normals and non paranoid than for paranoid schizophrenics; and ear differences were biggest for the paranoid schizophrenics and smallest for the normals. The results were interpreted in terms of differences in attentional style and rate of information processing.

Interictal regional cerebral blood flow in patients with partial seizures

Interictal regional cerebral blood flow was determined in 11 adult patients with partial epilepsy and lateralized electroencephalographic abnormalities by means of the xenon 133 intracarotid injection method. A hemispheric area demonstrating significantly low regional cerebral blood flow values as compared with the hemispheric mean cerebral blood flow was observed in each of the patients. In 10 of the 11 patients the localized reduced regional cerebral blood flow levels deviated significantly from levels obtained from parallel regions and hemispheres of normal controls. In the majority of patients, the site of low regional cerebral blood flow closely correlated with the clinical type of partial seizures and/or the site of main electroencephalographic abnormality. On the basis of these data, we suggest that the epileptogenic focus responsible for the partial seizures may be localized within the hemispheric area demonstrating the abnormal regional cerebral blood flow reduction.

Hypertension and Diabetes as Risk Factors in Stroke Patients

The occurrence of hypertension and diabetes in stroke patients was evaluated in a retrospective epidemiological study in the Jerusalem district. During the years 1960 through 1967, 1,522 new stroke cases (834 males and 688 females) were diagnosed and included in the study. Cerebral ischemia was diagnosed in 509 patients (33%), 181 patients (12%) had an intracerebral or subarachnoid hemorrhage and 832 patients (55%) had a stroke of undetermined type. For the total stroke series, 42% had hypertension. Almost the same percentage was found for males (41%) and females (43%). There was almost no sex predominance in the hypertensive stroke cases in the different age groups and for the various types of stroke. The frequency of hypertension among the stroke cases was low in the 40 to 49 age group, higher in the 50 to 59 age group, maximal in the 60 to 69 age group, and declining in the above 70 age group. The percentage of hypertensives was about the same for the ischemic and the undetermined types of stroke and for the total stroke series in the different age groups. It was found to be slightly higher in the hemorrhage type. The prevalence of hypertension among the male stroke cases was compared with the prevalence of hypertension in the general male population aged 40 and above (9.6%). For the total stroke series, 20% had diabetes. The same percentage was found for males (19%) and females (20%). There was almost no sex predominance in the diabetic stroke cases in the different age groups and for the various types of stroke. There was no significant change in the distribution of diabetes in the various age groups and the different stroke types. The prevalence of diabetes among the male stroke cases was compared with its prevalence in the general male population aged 40 and above (5%). Our study shows that hypertension and diabetes play an important role as risk factors in the development of cerebral ischemia and hemorrhage alike.

A physiological vascular correlate of hand preference: possible implications with respect to hemispheric cerebral dominance.

Abstract The present investigation was an attempt to find a physiological correlate of cerebral dominance which is manifested also by hand preference. As yet no morphological or physiological correlates of this kind have been demonstrated in normal subjects. The guiding idea was to search for such a correlate in the assymetry of the blood supply to the brain. Using a simple clinical method, ophthalmodynamometry, in 110 young healthy subjects, it was found that the systolic (and to a lesser degree, the diastolic) ophthalmic artery pressures, were higher on the right side of most right handed subjects, higher on the left side of most left handed subjects, and equal in both sides of most ambidextrous subjects. No similar pattern was found with respect to the brachial artery pressures. As the ophthalmic artery pressure is an accepted indicator of the pressure in the carotid artery, it is suggested that cerebral dominance and interhemispheric behavioral differences are determined, to some degree at least, by the differences in the blood supplies of the two cerebral hemispheres.

Disturbances of Tactile Sensitivity in Patients with Unilateral Cerebral Lesions

Summary The primary purposes of this study were to determine the relative frequency with which patients with unilateral cerebral disease show bilateral or ipsilateral defects in tactile sensitivity and to determine whether patients with lesions of the left hemisphere differ from those with lesions of the right hemisphere in this regard as well as with respect to pattern of tactile performance. The absolute pressure threshold, the differential pressure threshold and tactile resolution (two-point discrimination threshold) on the contralateral and ispilateral hands were measured in patients with unilateral cerebral disease. The same determinations were made for the right and left hands in a group of control patients without evidence of history of cerebral disease. The major findings of the study were: (1) Bilateral or ipsilateral impairment in tactile sensitivity was shown by a substantial number of patients with unilateral cerebral disease. (2) Patients with disease of the left hemisphere showed essentially the same frequency of bilateral or ipsilateral defects as did patients with disease of the right hemisphere. (3) The three sensory measures showed significant positive correlations for the contralateral hand in both hemispherically damaged patients. However, the two groups differed with respect to performance pattern on the ipsilateral hands; while the three measures were positively intercorrelated for the ipsilateral (left) hand of the patients with lesions of the left hemisphere, the correlation coefficients among the same measure for the ipsilateral (right) hand of the patients with lesions of the right hemisphere were small and non-significant. (4) Performance on the sensory tests across the two hands was found to be positively intercorrelated in all three groups of patients.

Correlation between regional cerebral blood flow and EEG frequency in the contralateral hemisphere in acute cerebral infarction.

The relationship between the rCBF and the electroencephalographic (EEG) frequency was investigated in the contralateral hemisphere of 22 patients with acute cerebral infarction. Reduced rCBF was observed in all patients studied. The degree of rCBF reduction was mild, moderate, or severe and ranged between 6 and 80% from the lowest age-matched normal values obtained in our laboratory. The frequency indices remained within normal limits (mean - 10.4 Hz) in 16 patients. Slower frequencies (mean - 6.3 Hz) were recorded in 6 patients. No correlation was found between the two parameters (P = 0.89). Both the EEG frequency and the rCBF are known to be closely related to the cerebral metabolic rate. The observed rCBF depression without concomitant changes in the EEG frequency raises the question of the role of globally-reduced cerebral metabolism as the cause of rCBF reduction in the noninfarcted hemisphere in stroke patients. Our findings constitute additional evidence that the contralateral hemisphere is involved in the haemodynamic changes occurring in acute cerebral infarction.