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Biomedical subjects

G Fein

Publications and source records attributed to G Fein.

At least 109 records · Page 6Linked to original sources
PubMed1986

EEG asymmetry in schizophrenic patients before and during neuroleptic treatment.

Lateral asymmetry of electroencephalographic (EEG) spectra was assessed in schizophrenic patients compared to normal controls. Ten predominantly unmedicated schizophrenic inpatients and nine normal controls performed monitored cognitive tasks during bilateral recording of EEG from parietal and temporal sites. Lateralization of EEG power in five frequency bands was compared between the groups; separate analyses were performed for linked ears and vertex references. A subsample of schizophrenic patients was restudied after a period of neuroleptic treatment. All significant group differences were obtained with the linked ears reference only. Pretreatment schizophrenics manifested relatively less alpha power over the right hemisphere during all conditions than controls, particularly in the parietal leads. After treatment, there was a significant shift in alpha lateralization toward the control values. These latter effects were also present in the theta frequency band to a lesser extent.

Adult↗
PubMed1986

EEG spectra in dyslexic and control boys during resting conditions.

We studied the resting eyes open and eyes closed EEG in carefully screened samples of 9-13-year-old dyslexic and control boys within a 2-cohort cross-validation design with repeat testing 1-3 years later. We found: no difference between groups in delta or theta activity in either cohort or in repeat testing 1-3 years later; in the dyslexics, decreased beta (19-24 c/sec) activity at bilateral central, parietal and mid-temporal leads referenced to vertex; inconsistent group differences in the alpha band: the first cohort dyslexics had lower alpha power than did the controls, but there was no group difference in the second cohort; and significant relative delta differences between groups in the first cohort, which were shown to be a statistical artifact of the use of relative power. We conclude that: dyslexia per se is not associated with increased absolute power in the delta and theta bands; lower power in the high beta band is reliably found in these samples of dyslexics without other disorders; and alpha power levels are not consistently lower in the dyslexic group.

Alpha Rhythm↗
PubMed1986

Neurometrics does not detect 'pure' dyslexics.

Thirty-eight severely dyslexic boys and 38 good readers were evaluated with neurometrics, a diagnostic procedure based on the application of numerical taxonomy to EEG spectra obtained during resting conditions, supplemented by selected evoked potential features. This procedure generates deviance scores for the EEG spectra by comparing each individual's values to those obtained from a normative population and has been reported to discriminate learning disabled children from normal controls (Ahn et al. 1980). In the present study, all subjects, dyslexic and control, passed stringent screening to assure normal intellectual, neurological, sensory and emotional status. The false positive rate obtained in our control group was comparable to that reported earlier. However, none of the deviance scores significantly discriminated dyslexics from controls; most subjects from both groups were classified as normal. Severe dyslexia per se is thus not associated with the specific neurometric abnormalities reported previously in more heterogeneous learning disabled populations.

Adolescent↗
PubMed1986

Sleep spindles in normal elderly: comparison with young adult patterns and relation to nocturnal awakening, cognitive function and brain atrophy.

Visual measurements of sleep spindles were carried out in 48 elderly and 20 young normal adults. Computed tomography brain scans and psychometric testing were also performed. Earlier findings of reduced spindle abundance, amplitude and duration in the elderly were confirmed. In addition, we demonstrated a linear increase in spindle density and duration across NREMPs in young adults that was absent in the elderly, indicating that age affects the temporal pattern as well as the quantity of spindles. Contrary to what seemed a highly plausible hypothesis, the amount of waking in the elderly was not inversely correlated with spindle abundance, confirming earlier observations (Feinberg et al. 1967) but in a much larger group. This finding suggests that spindle abundance does not reflect the integrity of the systems that maintain the brain in NREM sleep. We also were unable to show any clear evidence that relative preservation of spindles in the elderly is associated with relative preservation of cognitive skills: psychometric performance and spindle measures were, in most instances, not significantly correlated. However, the test of this hypothesis was limited by the high level of function and the narrow range of impairment of these Ss. One intriguing positive finding was the significant inverse relation between ratings of sulcal atrophy and spindle amplitude. This observation suggests an etiology for the reduced amplitude of the sleep EEG in old age. This change is one of the most striking effects of age on brain electrophysiology.

Adult↗
PubMed1986

Narrative speech deficits in dyslexics.

Narrative speech of 31 dyslexics and 33 good readers was studied. Subjects were 10- to 12-year-old right-handed boys of normal intelligence, and with normal neurological status, vision, and hearing. The dyslexics used shorter communication units (independent clauses with all their modifiers), and a higher percentage of their words were noncommunications (words which are extraneous to the speaker's intended meaning). Rate of speech was the same in both groups. These findings were replicated in an independent second cohort of 21 dyslexics and 21 controls, aged 9 to 13. Our findings support theories of a general language deficit in dyslexia, and demonstrate the involvement of the previously unexamined area of narrative speech.

Adolescent↗
PubMed1984

Log amplitude is a linear function of log frequency in NREM sleep eeg of young and elderly normal subjects.

The log of the amplitude of EEG waves during NREM sleep is a linear function of the log of their frequency. The slope of this function is reliable within individuals, is significantly less steep in elderly than in young subjects and, in both groups, becomes flatter across successive NREM periods. We interpret these results as consistent with the hypothesis that the function of NREM sleep is to reverse the effects of waking on the brain. According to this model the decreased steepness of slope in the elderly and in later NREM periods reflects the diminishing intensity of these processes. Whatever the correct interpretation, the within-subject consistency of slope values permits their empirical study as a function of experimental manipulations. In addition, the quantitative F-A function established here (A = c/Fb) sets constraints that may prove useful for physiologic models of EEG waves during sleep.

Adult↗
PubMed1984

EEG spectra in 9-13-year-old boys are stable over 1-3 years.

Good reliability was found in EEG spectra recorded during resting conditions in two studies 1-3 years apart in groups of adolescent dyslexic and control boys who were well screened for neurological, sensory and emotional disabilities. The studies used different equipment and analysis (FFT in study 1 vs. iterative digital bandpass filters in study 2). The central leads (C3 and C4) referenced to vertex were recorded in both studies. Pearson correlation coefficients were computed as reliability estimates for each spectral band separately for each group, for absolute and relative power and for eyes open and eyes closed recording conditions. For both groups and for all conditions, the absolute power reliabilities were above 0.71 for all bands except delta for which they were above 0.54. Reliabilities were more variable for relative power measures.

Adolescent↗
PubMed1984

Regional brain activity in dyslexic and control children during reading tasks: visual probe event-related potentials.

Event-related potentials (ERPs) elicited by task-irrelevant visual stimuli were recorded from 34 control and 32 dyslexic 10- to 12-year-old boys while they performed silent and oral reading at two levels of difficulty. All subjects were extensively screened for neurological problems, IQ, and sensory acuity. Specific features of the ERPs were affected in amplitude and latency by the experimental variables: group membership, oral vs. silent reading, difficulty level, and recording site (within and between hemispheres). A specific effect of difficulty on the central and parietal ERP was seen in the dyslexics but not the controls. Different patterns of asymmetry were found for the two groups in silent vs. oral reading at midtemporal placements. A marked asymmetry (R greater than L) was found at the midtemporal region for both groups.

Attention↗
PubMed1983

Lake Michigan fish consumption as a source of polychlorinated biphenyls in human cord serum, maternal serum, and milk.

Reported consumption of Lake Michigan sport fish was examined in relation to the levels of polychlorinated biphenyls (PCBs) in biological samples provided by a sample of maternity patients. Fish consumption was correlated with PCB levels in maternal serum and milk but not in cord serum. PCB levels in serum increased with age, but were unrelated to social class, parity, or weight. Women who breast fed consumed as much fish as women who did not and their maternal and cord sera PCB levels were similar.

Animals↗
PubMed1983

A canine model of acute coronary artery stenosis: effects of deliberate hypotension.

Coronary artery disease is considered a contraindication to inducing hypotension during surgery because the combined effects of stenosis and hypotension in reducing distal coronary artery perfusion pressure might produce myocardial ischemia. To study the effect of deliberate hypotension (mean systemic pressure, 50 mmHg) on regional myocardial perfusion, oxygenation, and lactate extraction, we constricted the left-anterior descending coronary artery (LADCA) in dogs. Two degrees of stenosis were studied: "critical" stenosis, which reduced resting coronary blood flow from 34.4 to 31.2 ml/min and abolished reactive hyperemia of the LADCA in response to 10 s of total coronary artery occlusion; and a more "severe" stenosis, which reduced resting coronary blood flow by 40%. LADCA pressure was measured distal to the stenosis, and LADCA perfusion pressure was obtained by subtracting the left ventricular end-diastolic pressure from the coronary artery diastolic pressure measured past the stenosis. Hypotension was induced by administering sodium nitroprusside, halothane at a high concentration, or trimethaphan. Lactate extraction and oxygen consumption were measured across the myocardium distal to the stenosis (from the coronary artery to the great cardiac vein) and across the whole heart (from the coronary artery to the coronary sinus). Regional myocardial blood flow was measured using radioactive microspheres. A transmural electrocardiogram was obtained from electrodes implanted in the subendocardium and the subepicardium in the distribution of the LADCA distal to the stenosis. Although the combination of critical stenosis and hypotension reduced regional myocardial blood flow and lowered LADCA perfusion pressure to 27 +/- 3 (SE) mmHg, myocardial ischemia did not occur, as evidenced by continued lactate extraction and no redistribution of transmural blood flow or change in ST segment. On the other hand, the combination of severe stenosis and hypotension reduced LADCA perfusion pressure to 17 +/- 2 (SE) mmHG and produced evidence of ischemia by regional lactate production, reduction of the subendocardial/subepicardial flow ratio, and depression of the ST segment.

Animals↗
PubMed1980

Comprehensive viral immunology of multiple sclerosis. I. Clinical, epidemiological, and CSF studies.

Epidemiological, clinical, and CSF data were collected on 87 patients with clinically definite multiple sclerosis (MS) and 50 with probable MS. As part of a study of immunologic reactivity to viral antigens, a control group separated into 26 patients with probable inflammatory neural disease and 140 with noninflammatory neural disease was similarly studied. Among the groups with MS, females predominated and both Oriental and Spanish surnamed patients were under-represented. The spinal cord, optic nerves, and brainstem were the most common sites of initial disease and more than 20% of the patients had only cord symptoms after several years of disease activity. Of several CSF assays used, determination of oligoclonal IgG bands by agarose electrophoresis was most useful diagnostically.

Adolescent↗
PubMed1980

Comprehensive viral immunology of multiple sclerosis. II. Analysis of serum and CSF antibodies by standard serologic methods.

Sera and CSFs of 85 patients with multiple sclerosis (MS), 49 patients with probable MS, and 165 control patients with other neurologic diseases were assayed for antibodies to rubella, mumps, measles, parainfluenza I (strain 6/94), herpes simplex, cytomegalovirus, varicella-zoster, and vaccinia viruses. Methods included complement fixation (CF), hemagglutination inhibition (HI), and complement-dependent plaque reduction (CPR). Significant differences between the groups with MS and the control groups were higher serum antibody titers to measles virus in the groups with MS, higher proportion of patients with MS with CSF antibodies to measles, rubella, and vaccinia viruses, and greater percentage of patients with MS with more than one CSF viral antibody. Duration and severity of disease in the patients with MS were associated with presence of multiple CSF antibodies. Presence of CSF antibody was positively correlated with the height of the correspnding serum titer, yet a high serum titer did not ensure the presence of CSF antibody. Oligoclonal bands were present in the CSFs of equal proportions of patients with MS with and without CSF viral antibody. Our data support the hypothesis of local antibody synthesis within the CNS. However, we favor the view that preprogrammed antibody-forming lymphocytes enter the CNS and then produce antibody either because of nonspecific polyclonal activation in situ or because of failure of normal regulation.

Antibodies, Viral↗
PubMed1980

Comprehensive viral immunology of multiple sclerosis. III. Analysis of CSF antibodies by radioimmunoassay.

The CSF from 279 patients with multiple sclerosis (MS), probable MS, or controls was examined by radioimmunoassay (RIA) for antibodies to measles, rubella, mumps, parainfluenza 1 (Sendai) (strain 6/94), herpes simplex (HSV), varicella, and vaccinia viruses. Significantly more patients with MS than noninflammatory control patients had antibody to measles, rubella and varicella viruses, of which antibody to measles was the most prevalent. The percentage of patients with MS with two or more CSF antibodies was significantly greater than that in the controls. There was no tendency for certain antibodies to be associated. There was a general relationship between presence of CSF antibodies and severity of MS. The data support the hypothesis of local CNS antibody synthesis of several viral antibodies; however, such local synthesis may be a random event, possibly dependent on the number and specificity of peripheral virus antibody-forming lymphocytes available for ingress into the CNS.

Albumins↗