Left and right-handed dyslexic boys: an empirical test of some assumptions of the Geschwind-Behan hypothesis.

Twenty-six dyslexic boys (13 left-handers and 13 right-handers) were tested for hemispheric asymmetry with dichotic listening (DL) and a visual half-field test (VHF). The purpose of the study was an empirical test of the Geschwind-Behan [Proc. natn. Acad. Sci. USA 79, 5097-5100, 1982] hypothesis of a difference in hemispheric asymmetry between left- and right-handed dyslexic boys. Following Geschwind and Behan, left-handedness and dyslexia are caused by a common factor affecting the development of the left hemisphere in utero which results in a right hemisphere dominance. As a consequence, handedness but not language is shifted to the right hemisphere. We therefore predicted that left-handed dyslexics should be superior to right-handed dyslexics on visuospatial tasks, but perform similar to right-handers on verbal tasks. The results revealed a significant right ear advantage (REA) in both groups during a dichotic listening test to verbal stimuli. The left-handed group was however superior to the right-handed group in recognition of visuo-spatial stimuli presented in the left half-field in a visual half-field test. It is concluded that the results provide some, although weak, support for the Geschwind-Behan hypothesis.

Memory functions in persons with dental amalgam.

Memory and psychophysiological variables in persons with self-reported reactions to dental amalgam (amalgam patients: N=26) and in persons without such symptoms (controls: N=21) were compared. The groups were matched regarding age, education, and amount of amalgam. Wechsler Memory Scale-Revised was obtained for all subjects and compared to amalgam points in a dose-response design. The results demonstrated that amalgam patients function on the same level as the controls regarding memory variables, attention, concentration, and delayed recall. Psychophysiological measures of skin conductance as correlates of attention and basal memory functions, were compared in the two groups. No differences between the two groups were observed and no correlation between memory variables and exposure to amalgam could be detected.

Differential neuropsychological effects of diving to 350 meters.

Six divers were compressed on heliox to 350 m. Repeated neuropsychological and neurological tests were conducted during the dive. Averaged increased tremor during the compression was found. Two divers had major EEG changes, while two divers had a completely normal EEG. Memory was most impaired among the cognitive variables. At 350 m there was some normalization in the EEG, and the tremor levels returned to normal. Memory impairment, however, was sustained. Three months later nine divers performed an open sea dive to 300 m. Whereas minor fatigue effects were found for the experimental dive, examinations after the open sea dive indicated more specific cerebral after effects. An increased tremor, reduced hand grip strength and foot tapping speed, lowered autonomic reactivity, and memory problems were found. Some divers had unequivocal asymmetrical plantar responses and unilateral weak abdominal reflexes, accompanied by EEG changes with corresponding laterality. In three of the divers these signs were not present 1 month later.

Activation, arousal, and neuropsychological rehabilitation.

This paper addresses the concept of arousal and the role of the reticular system in producing the orienting response. For patients with deviant autonomic responses, the use of central neuropharmacological stimulants is considered. Their therapeutic value is discussed in relation to hyperactive children and individual adult cases of the posttraumatic syndrome consequent upon traffic accidents.

[Clinical neuropsychology]. / Klinisk neuropsykologi.

The article reviews the development of clinical neuropsychology as a professional discipline and comments on important contributions from various research fields and clinical disciplines. The consequences of disturbances in the neurotransmitter systems for neuropsychological functioning are discussed, as well as various clinical issues and the applications of clinical neuropsychology, and of neuropsychological evaluations.

MMPI patterns in chronic muscle pain, tension headache, and migraine.

MMPI personality profiles were obtained from three clinical groups (n = 79). One group consisted of men and women with chronic muscle pain (MP; n = 34), a second group of male and female chronic tension headache patients (TH; n = 12), and a third group of female migraine patients (M; n = 33). The M group was subdivided on the basis of source of referral and into groups of classic versus common migraine. Elevation of the MMPI subscales usually interpreted as neuroticism scales were found in all groups. A "psychosomatic V" pattern was found on these scales in the M group but not in female TH patients. The difference in scale configuration between groups was caused primarily by different elevations on the depression scale. A relationship between severity of headache and elevation of the "psychosomatic V" was found in migraine patients. Male MP and TH patients showed a descending slope on the neuroticism scales, not observed in females. There was a tendency for common migraine patients to show a more elevated and psychosomatic configuration on the MMPI, as compared with classic migraine patients.

MMPI profiles in migraine before and after biofeedback treatment. Minnesota Multiphasic Personality Inventory.

Migraine has been associated with specific personality traits. Typically, migraine patients show elevation on the "neurotic scales" on the MMPI, and the profiles usually reported can be classified as "psychosomatic". A crucial matter is whether certain personality traits predispose to headache problems or whether they are an effect of such problems. To elucidate this problem, common and classic migraine patients (n = 13) were evaluated with the MMPI before and 2 years after biofeedback treatment. Two subgroups were identified on the basis of degree of clinical improvement. The least improved patients were significantly older and had a significantly longer headache history than the patients showing most improvement. No relationships between age, headache history, and improvement were found within subgroups. Clinical improvement was correlated with significant "normalization" of the MMPI profiles. Thus, personality traits as measured by the MMPI seem to be secondary to headache problems and not a predisposing cause.

Neuropsychological deficits in HIV-1 seropositive and seronegative intravenous drug users (IVDUs): a follow-up study.

Human immunodeficiency virus type 1 (HIV-1) seropositive AIDS free and HIV-1 seronegative intravenous drug users were tested twice with a comprehensive neuropsychological test battery. Only minor group differences were found. Memory difficulties were the most pronounced difference with lower scores in the HIV-1 seropositive group. The memory difficulties were to some degree associated with emotional difficulties, that is, anxiety. The HIV-1 seropositive subjects were tested a third time and there was no further decline in any test with memory content at this testing. The only test that showed a significant decline in the HIV-1 seropositive group was the Trail Making Test.

Psychological difficulties related to human immunodeficiency virus-1 infection in intravenous drug users.

Psychopathology and emotional changes were examined over a 9-month period in this study of human immunodeficiency virus-1 (HIV-1) infection in seronegative and seropositive intravenous drug users. The HIV-1-seropositive group showed more psychological difficulties and emotional distress at both testings. For the HIV-1-seronegative subjects, a trend for less psychopathology and psychological distress was found. At the second testing, the difference between groups was increased due to improvement of the HIV-1-seronegative group. A more chronic course of psychological distress was found in the HIV-1-seropositive group.

Neuropsychologic effects of saturation diving.

Neuropsychologic status of saturation divers was assessed before and after 300-500 msw dives (deep saturation diving--DSD group) and before and after 3.5 yr of ordinary saturation diving (saturation diving--SD group). Average baseline results showed the divers to be slightly superior to nondiving controls. Mild-to-moderate neuropsychologic changes (greater than 10% impairment) were found in measures of tremor, spatial memory, vigilance, and automatic reactivity in 20% of the divers after deep dives (DSD group). One year postdive no recovery was observed except for a vigilance test. In the SD group, 20% of the divers showed greater than 10% impairment after 3.5 yr of ordinary saturation diving. Significant reduction in autonomic reactivity was also found and there was a relationship between low autonomic reactivity before saturation diving and number of greater than 10% impairments. For the whole group (DSD + SD divers), negative correlations were found between saturation experience and results on memory and complex visuomotor tests. Years of diving from first to last examination was positively correlated with number of greater than 10% impairments and with reduction in autonomic reactivity. No similar correlations were found to dive variables after about 3 yr of air diving. The mild-to-moderate changes seen in some divers, therefore, seem to be the effects of saturation diving. Since one deep dive may cause an effect similar to the effect of 3.5 yr of ordinary saturation diving, there is reason to believe that repeated deep diving may lead to more pronounced neuropsychologic impairment.

Neuropsychological deficits in HIV-1 seropositive and seronegative intravenous drug users.

A battery of neuropsychological tests was administered to detoxified HIV-1 seropositive and seronegative intravenous drug users. There were few problems related to administering the test battery to the groups in question. Of the total sample, 28% obtained an Halstead-Reitan Impairment Index > .4, indicating central nervous system deficits. Both groups performed below comparable normative levels on the variables studied. The HIV-1 infection per se could not explain the neuropsychological impairment.

The effect of the stimulant drugs, dextroamphetamine and methylphenidate, on secretion of growth hormone in hyperactive children.

The stimulant effect of L-dopa (125 to 500 mg) was compared to dextroamphetamine and methylphenidate, 15, and 20 mg, respectively, on growth hormone secretion in 20 hyperactive children. All three stimulants were responsible for peak GH concentration in serum at 60 minutes after drug ingestion; there was no significant difference between the mean GH level at any time of sampling. Seven of the children were retested with L-dopa and dextroamphetamine after six to eight months of treatment with methylphenidate. After treatment, there was a tendency to higher zero time levels of GH, and to delayed and/or paradoxical response to dextroamphetamine. The findings indicate an acute and a probably long-term effect of dextroamphetamine and methylphenidate on the homeostasis of growth hormone. The possible long-term adverse effects of these drugs on the growth of children indicates the need for caution to the widespread use of these agents.