Biomedical subjects
Publications and source records attributed to N Geschwind.
An acute confusional state after infarction in the distribution of the right middle cerebral artery has been described. Patient recovery usually is excellent. Some patients, however, do not improve, resulting in a chronic confusional state.
Forms containing the Edinburgh handedness inventory and questions about learning disabilities, hair color, self-described handedness, age, gender, parental handedness and twinning were received from 1117 randomly selected professionals. Laterality scores (LS, range -100 to +100) were calculated for each respondent based on the handedness inventory and were correlated with the above variables. Among blonds, the frequency of non right-handedness (NRH, LS less than or equal to 70) was 44% compared to 24% of non-blonds (chi 2 = 23.5, P less than 0.0001). Learning disabilities (LD) were present in 9% of NRH (LS less than or equal to 70) as against 3% of those with LS greater than 70 (chi 2 = 22.1, P less than 0.0001). Associations between LS and self-described handedness, parental handedness, gender, and age are also presented. Possible explanations for the association of hair color and handedness are discussed in light of recent data on altered visual system pathways in albinos. Problems in the measurement of handedness are discussed.
Of 50 consecutive women with partial seizures of temporal lobe origin (temporal lobe epilepsy [TLE]) evaluated for reproductive dysfunction, 28 had menstrual problems. Of those, 19 had reproductive endocrine disorders. Polycystic ovarian syndrome and hypogonadotropic hypogonadism occurred significantly more often in women with TLE than in the general female population. Polycystic ovarian syndrome was associated with predominantly left-sided lateralization of interictal epileptic discharges; hypogonadotropic hypogonadism was more commonly found with right-sided discharges. Hyposexuality occurred more often in women with predominantly right-sided interictal epileptic discharges and was associated with low serum luteinizing hormone levels. There are several possible interpretations: epileptic discharges in medial temporal limbic structures may disrupt hypothalamic regulation of pituitary gonadotropin secretion; anovulatory cycles of reproductive endocrine disorders may promote the development of epileptic discharges; and TLE and some associated reproductive endocrine disorders may represent the parallel effects of prenatal factors common to the development of the brain and the reproductive system.
Twenty consecutive men with partial seizures of temporal lobe origin were evaluated for sexual or reproductive dysfunction. Eleven (55%) had diminished sexual interest or reduced potency. Nine of them had reproductive endocrine disorders, with features of hypogonadotropic hypogonadism in five, hyperprolactinemia in two, and hypergonadotropic hypogonadism in two. Among these nine were cases in which the reproductive endocrine abnormalities could not readily be attributed to antiseizure medication use. Other possible interpretations are as follows: epileptic discharges in medial temporal lobe structures may disrupt hypothalamic regulation of pituitary secretion, hypogonadism may promote the development of epileptic discharges, and temporal lobe epilepsy and associated reproductive endocrine disorders may represent the parallel effects of prenatal factors common to the development of both the brain and the reproductive system.
Most theories about the inheritance of hand preference assume that handedness is a unidimensional trait which forms a continuous distribution. This paper demonstrates that sampling a wide range of manual activities reveals dimensions of hand preference that are independent. 180 right handed and 110 left handed adults indicated their hand preference for 55 activities according to a five point scale. A Varimax Factor Analysis revealed four factors which accounted for 80 percent of the variance. Factor 3 was of special interest because it represented behaviors which rely upon the axial musculature and involve strength more than dexterity. Hand preference for items on this factor were less laterally biased than on factors which included such fine motor behaviors as writing or drawing. These results suggest that manual preference is governed by more than one neural system and that these systems may be independently lateralized.
Despite 60 years of study, the brain mechanisms for stuttering are unknown. In an effort to shed light on these mechanisms, we studied two cases in which the fluency of speech changed after brain damage in adulthood. The first, an ambidextrous man, ceased to stutter after a head injury. The second, a converted left-handed man, experienced recurrence of childhood stuttering after a stroke.
Deficits in cognition and behavior have frequently been described in severely depressed patients. Recent reports have drawn attention to focal left-sided neurologic findings occurring in depression. We describe a depressed patient with marked cognitive and behavioral impairment and focal left-sided signs. The depression, mental status deficits, and physical findings all resolved after electroconvulsive therapy.
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We report the neuroanatomical findings in 4 consecutively studied brains of men with developmental dyslexia. The patients, who ranged in age between 14 and 32 years, were diagnosed as dyslexic during life. Nonrighthandedness and several autoimmune and atopic illnesses were present in the personal and family histories. All brains showed developmental anomalies of the cerebral cortex. These consisted of neuronal ectopias and architectonic dysplasias located mainly in perisylvian regions and affecting predominantly the left hemisphere. Furthermore, all brains showed a deviation from the standard pattern of cerebral asymmetry characterized by symmetry of the planum temporale. The neuroanatomical findings in these 4 patients are discussed with reference to developmental cortical anomalies, cerebral asymmetries, reorganization of the brain after early lesions, and the association between learning disorders, left handedness, and diseases of the immune system.
Cortical anomalies have been reported in the brains of dyslexic individuals. In addition, dyslexic and left-handed individuals have a higher than expected rate of some immune-related diseases. The possible association between immune and cerebrocortical pathology was investigated in the immune-defective New Zealand Black mouse and its hybrid with the New Zealand White mouse. Structural anomalies similar to those present in the dyslexic brain were seen in the brains of these mice.
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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.
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