ABSTRACT
Patients who had their speech dominance determined by carotid Amytal testing were evaluated with a dual task procedure consisting of reading and finger tapping. As expected, the asymmetry of interference between tasks varied with speech dominance. Patients with left hemisphere speech tended to show greater interference in the right hand whereas patients with right hemisphere speech showed greater interference in the left hand. Since the right hemisphere dominant patients were also right-handed, the results suggest that interference effects are more closely linked to speech than to motor dominance.
Subject(s)
Amobarbital , Brain/physiology , Functional Laterality/physiology , Psychomotor Performance/physiology , Speech/physiology , Adolescent , Adult , Amobarbital/administration & dosage , Carotid Arteries , Child , Epilepsy/pathology , Epilepsy/psychology , Epilepsy/surgery , Female , Humans , Injections, Intra-Arterial , Magnetic Resonance Imaging , Male , ReadingABSTRACT
Variations in the size of the human corpus callosum were examined as a possible morphological substrate of functional asymmetries of the cerebral hemispheres, such as cerebral speech dominance. The midsagittal surface area of the corpus callosum, obtained by magnetic resonance imaging, was measured in 50 patients with epilepsy and 50 neurologically normal control subjects. The mean callosal area did not differ significantly between patients and control subjects, between left-handed and right-handed subjects, or between men and women. When measurements were compared among 44 patients, whose cerebral speech dominance had been determined by the intracarotid injection of sodium amytal, the area of the corpus callosum was significantly greater in patients with right-hemisphere cerebral speech dominance. The mean callosal area was greater by 109 to 159 square millimeters (18-28%) when compared to that of patients with either left-hemisphere speech dominance or bilateral speech representation. This difference in midsagittal surface area could represent as many as 37 to 54 million additional callosal axons in subjects with right-hemisphere cerebral speech dominance.
Subject(s)
Brain/physiology , Corpus Callosum/anatomy & histology , Dominance, Cerebral , Speech , Adolescent , Adult , Brain/anatomy & histology , Brain/physiopathology , Child , Corpus Callosum/physiology , Corpus Callosum/physiopathology , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Reference Values , Seizures/physiopathologyABSTRACT
Twenty-four medically refractory seizure patients, who did not qualify for excisional surgery, had anterior two-thirds corpus callosum section. Three to 11 years' postoperative follow-up suggests that this procedure can (1) lateralize a frontal lobe focus, which may lead to subsequent localized excision and (2) significantly reduce seizure frequency and severity in 75% of the patients without giving any permanent neurologic deficits. Patients with an ictal focus confined to one frontal lobe did best (8/8 improved), followed by patients with secondarily generalized seizures and multifocal bilateral foci (5/6 improved). Patients with mental retardation benefited less frequently (5/10 improved), but 4/4 from this group with ictal falls associated with Lennox-Gastaut syndrome did benefit. In this series, the improvements following the anterior partial section were lasting if present at 1 year of follow-up. Anterior corpus callosum section should be considered as a diagnostic (lateralizing) and therapeutic option in appropriately defined medically refractory patients who do not qualify for excisional surgery.
Subject(s)
Corpus Callosum/surgery , Seizures/surgery , Adolescent , Adult , Female , Follow-Up Studies , Humans , Male , Middle Aged , Psychological Tests , Seizures/psychologyABSTRACT
We describe an epileptic syndrome of bilaterally coordinated limb movements, axial movements, vocalization, and nonmasticatory oral activity. EEG and physiologic evidence indicates the syndrome is caused by ictal discharge in the mesial frontal lobes. Two of 12 patients were not helped by anterior temporal lobectomy, and 3 others improved after section of the anterior two-thirds of the corpus callosum.
Subject(s)
Epilepsies, Partial/physiopathology , Frontal Lobe/physiopathology , Adolescent , Adult , Corpus Callosum/surgery , Electroencephalography , Epilepsies, Partial/surgery , Female , Humans , Male , Middle Aged , Motor Activity/physiologyABSTRACT
A right-handed woman with independent left- and right-sided temporal lobe discharges was studied by continuous EEG and videotape monitoring for 3 weeks. Changes in affect were noted in the immediate and extended postictal periods and varied with the side of discharge. After a left-sided discharge, she became globally aphasic and depressed. Right-sided discharges evoked laughing and postictal hypomania. These manifestations were attributed to contralateral hemispheric disinhibition after ipsilateral seizure inactivation. This case provides evidence that the speech-dominant hemisphere subserves positive feelings and the nondominant hemisphere negative ones.
Subject(s)
Brain/physiopathology , Epilepsy, Temporal Lobe/physiopathology , Adult , Dominance, Cerebral , Electroencephalography , Female , Humans , Mood Disorders/physiopathologyABSTRACT
Epileptic patients whose speech dominance had been ascertained using the carotid Amytal test were given a verbal-visual half-field task. Patients with left-hemisphere speech dominance, like normal controls, tended to show a RVF effect whereas patients with atypical speech patterns showed a bias in favor of the LVF.
Subject(s)
Dominance, Cerebral/physiology , Speech/physiology , Visual Perception/physiology , Adolescent , Adult , Amobarbital , Epilepsy/physiopathology , Female , Humans , Male , Middle Aged , Visual FieldsABSTRACT
Morphological asymmetry of the posterior sylvian region was measured in carotid arteriograms of patients with medically refractory seizures. Anatomical asymmetry correlated with ear superiority on dichotic listening tests.
Subject(s)
Dominance, Cerebral/physiology , Language Development , Speech Perception/physiology , Adolescent , Adult , Cerebral Angiography , Humans , Middle Aged , Parietal Lobe/physiology , Temporal Lobe/physiology , Tomography, X-Ray ComputedABSTRACT
Levy and Reid's claim (1976, 1978) that writing hand/posture is predictive of cerebral dominance was examined in patients who had undergone bilateral sodium Amytal speech testing. Contrary to their prediction, inverted writers showed the same pattern of speech representation as did straight writers.
Subject(s)
Dominance, Cerebral , Functional Laterality , Speech , Adolescent , Adult , Amobarbital , Child , Dominance, Cerebral/drug effects , Epilepsy/diagnosis , Female , Functional Laterality/drug effects , Humans , Male , Middle Aged , Speech/drug effectsABSTRACT
Examination of the simultaneously recorded EEG and video taped behavior of patients during seizures activated by pentylenetetrazol-bemigride revealed a variety of spontaneous facial expressions at the electroclinical seizure onset. Neutral and sad expressions were observed most often, followed in frequency by expressions of fear, surprise, and happiness. Expressions of disgust and anger were rare. There was no consistent relation between side of seizure onset and type of spontaneous facial expression.
Subject(s)
Facial Expression/physiology , Seizures/physiopathology , Adolescent , Adult , Bemegride , Child , Child, Preschool , Electroencephalography , Emotions/physiology , Female , Humans , Male , Middle Aged , Pentylenetetrazole , Seizures/chemically induced , Statistics as Topic , Videotape RecordingABSTRACT
The first part of this review considers the empirical findings regarding the anatomical asymmetries that may be related to the left hemisphere's dominance for language. The review reveals that there are interhemispheric differences in the anatomy of the posterior sylvian region and of portions of the inferior frontal gyrus. In the second section, difficulties in attributing functional significance to these morphological asymmetries are discussed. The third section considers anatomical, behavioural and neurochemical asymmetries in animals and their relation to problems of human cerebral asymmetry.
