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Biomedical subjects

N Geschwind

Publications and source records attributed to N Geschwind.

At least 37 records · Page 2Linked to original sources

Temporal lobe epilepsy: an extrahypothalamic pathogenesis for polycystic ovarian syndrome?

In a random sample of 20 women with temporal lobe epilepsy (complex partial seizures, CPS), we found 5 women with the polycystic ovarian syndrome. This finding in a small sample suggests a fivefold overrepresentation of polycystic ovarian syndrome among women with CPS. Clinical and experimental data support the notion that CPS and polycystic ovarian syndrome either favor a mutual development or are parallel effects of a common pathogenesis.

Adult↗

Alexia without agraphia in a composer.

A 77-year-old composer had a left occipital lobe haemorrhagic infarct giving a severe reading disturbance with well-preserved writing and without appreciable aphasia. He continued to read music and to compose. His text- and music-reading performance under different conditions suggests that this unusual dissociation was primarily due to four factors. (1) He was unusually talented musically and inferred a great deal about the music he was reading. (2) The symbols of staff music notation are more visually distinctive than the symbols of phonetic language writing systems. (3) In staff music notation, pitch is represented ordinally, and other symbols are also distinguishable by their relative positions and sizes. (4) Music notation can be usefully read by interpreting it acoustically, kinaesthetically or in terms of formal musical concepts; in contrast to written language, it need not be interpreted referentially or in terms of auditory-verbal images. His disorder fits the classic visual-verbal disconnection account of alexia without agraphia and the contemporary view that music involves a family of related but distinct skills probably involving many brain areas in both hemispheres, although different cortical areas make characteristic contributions to different musical behaviours.

Aged↗

Interictal behavioral changes in epilepsy.

Common behavioral alterations associated with epilepsy include increased interest in philosophical and religious concerns, increased and extensive writing of a cosmic or philosophical nature, changes in sexual behavior, and aggressiveness. Psychological stress, the effects of anticonvulsant therapy, and the actual occurrence of seizures or convulsions can be ruled out as possible causes of the syndrome. It is speculated that these behavioral alterations are the result of an intermittent spike focus in the temporal lobe that leads to an alteration in the responsiveness of the limbic system. Thus, there is a heightened emotional response to many stimuli as well as a decrease in sexual responsiveness. In an effort to discover the cause of the high incidence of sexual alterations, abnormalities in response to luteinizing hormone-releasing hormone (LHRH) were found in a group of patients with partial complex seizures, some of whom had no overt sexual dysfunction and had never received anticonvulsant therapy.

Behavior↗

Disorders of attention: a frontier in neuropsychology.

There is an extensive behavioural neurological literature on so-called unilateral attentional disorders, but a striking paucity of papers on global disorders of attention, i.e. confusional states. However, confusional states are distinctive because: (1) they are the most common disturbance of the higher functions in clinical practice, by orders of magnitude; (2)they are the only disturbance of the higher functions from which all normal subjects have suffered; (3) they have characteristic clinical manifestations; (4) they are frequently misdiagnosed as progressive dementias, aphasia, memory disorders, and psychoses; (5) they are the only disturbance of the higher functions that commonly cause patients to produce statement that appear to be extremely witty; (6) they can be readily studied experimentally; (7) they are the most common cause of unconcern with or denial of illness. There are almost certainly several different forms of confusional state depending on the aetiology, the rate of development, the age, and the anatomical systems involved, but little classification has yet been carried on. Confusional states are most simply defined as disorders in which there is a loss of the normal coherence of thought or action. Among the striking clinical features are: (1) failure to pay attention, excessive distractibility, or failure to shift attention; (2) paramnesias, i.e. distortions of memory; (3) reduplicative phenomena, 'wild' paraphasias with 'propagation' of error, alterations of mood in many different directions; (4) isolated or predominant disturbance of writing (the most common cause of pur agraphia); (5) unconcern with or denial of illness; (6) apparently playful behaviour. While confusional states are usually attributed to 'global involvement of the brain' as a result of metabolic or toxic disorder, there are in fact many cases produced by focal infarctions inthe right hemisphere, which, in the experience of my department, is one of the commonest effects of cerebrovascular disease. Brief reference is made to the prognosis, and to the theoretical significance for cerebral dominance and the evolutionary development of cerebral dominance in non-human species.

Amnesia↗

Aphasia with predominantly subcortical lesion sites: description of three capsular/putaminal aphasia syndromes.

Nine cases of subcortical aphasia with capsular/putaminal (C/P) lesion sites demonstrated on computed tomographic (CT) scans were studied. Eight cases were occlusive-vascular in etiology and one was hemorrhagic. Three subcortical aphasia syndromes and three C/P lesion site patterns were observed. Patients with C/P lesion sites with anterior-superior white-matter lesion extension had good comprehension, grammatical, but slow, dysarthric speech, and lasting right hemiplegia. Patients with C/P lesion sites with posterior white-matter lesion extension across the auditory radiations in the temporal isthmus had poor comprehension, fluent Wernicke-type speech, and lasting right hemiplegia. Patients with C/P lesion sites with both anterior-superior and posterior extension were globally aphasic and had lasting right hemiplegia. Although these cases of C/P subcortical aphasia shared certain well-known features of Broca's and Wernicke's cortical aphasia syndromes, they did not completely resemble cases of either Broca's, Wernicke's, global, or thalamic aphasia in neurologic findings, CT scan lesion sites, or language behavior. Further study of the subcortical aphasias associated with these C/P lesion sites seems to be warranted.

Adult↗

Neuroendocrine dysfunction in temporal lobe epilepsy.

Since medial temporal lobe structures are involved in the modulation of endocrine function and temporal lobe epileptics commonly show personality changes that resemble endocrine disorders, the existence of neuroendocrine dysfunction in temporal lobe epileptics was investigated by comparing the response of serum luteinizing hormone levels with intravenous luteinizing hormone-releasing hormone infusion in patients and normal controls. Five of seven consecutive patients had response curves that fell almost entirely outside of the normal control range, and all seven had either baseline or peak values that were outside of the normal range. These findings suggest that hypothalamic-pituitary control of gonadotropin secretion may be altered among patients with temporal lobe epilepsy.

Adult↗

Hemispheric asymmetry in the expression of positive and negative emotions. Neurologic evidence.

Three retrospective studies were conducted to examine functional brain asymmetry in the regulation of emotion. In the first study, reports of 119 cases were collected of pathological laughing and crying associated with destructive lesions. Pathological laughing was associated with predominantly right-sided damage, whereas pathological crying was associated with predominantly left-sided lesions. In the second study, 19 reports detailing mood following hemispherectomy were collected; right hemispherectomy was associated with euphoric mood change. In the third study, lateralization of epileptic foci was assessed in reports of 91 patients with ictal outbursts of laughing (gelastic epilepsy). Foci were most likely to be predominantly left-sided. The findings are congruent with studies of the effects of unilateral brain insult on mood, and a general model of hemispheric asymmetry in the regulation of emotion is presented.

Adolescent↗

Left-handedness: association with immune disease, migraine, and developmental learning disorder.

We report an experimental study designed to test the following hypothesis derived from clinical observations: There is an elevated frequency in left-handed individuals and in their families of immune disease, migraine, and developmental learning disorders. In two separate investigations the frequency of these conditions was compared in strongly left-handed subjects and in strongly right-handed controls. In each of the investigations we found markedly higher frequencies of immune disease in the left-handers than in the right-handers. The rate of learning disabilities was also much higher in the left-handers than in the right-handers in both investigations. In a second study the frequency of left-handedness was compared in patients with migraine or immune disease and in general population control subjects free of these disorders. There was a higher frequency of left-handedness in patients with migraine and myasthenia gravis than in controls. We present a brief outline of a hypothesis that may account for an increased frequency of immune disease in left-handers and in their families.

Functional Laterality↗