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Biomedical subjects

B S Giesser

Publications and source records attributed to B S Giesser.

7 recordsLinked to original sources
PubMed1995

Event-related potential correlates of early processing in normal aging.

Auditory event-related potentials were recorded from normal elderly and young adult subjects during simple reaction time and discrimination conditions. In both response conditions, the stimuli were randomly presented, as in an auditory "oddball" paradigm. It was found that NA, an index of early information processing, was significantly delayed in the elderly. Although the latency of N1 was not significantly different between the groups, the latencies of N2 and P3 were significantly longer for the aged subjects. The amplitudes of N1, NA1, NA2 and N2 showed no group differences. The raw amplitude of P3 showed a group difference in topography: Pz was greater than Fz for the young group, but not for the aged. When the amplitudes of NA1, NA2, and P3 were scaled, however, the topography of these components showed no significant group differences. These findings suggest that the age-related slowing of later ERP components and behavior may be partially accounted for by delays in early attention dependent perceptual processes, as indexed by NA.

Adult↗
PubMed1992

Endogenous event-related potentials as indices of dementia in multiple sclerosis patients.

Auditory event-related potentials (ERPs) were recorded in a "double oddball" paradigm requiring an easy and a hard pitch discrimination from multiple sclerosis (MS) patients with and without dementia, and a group of age and sex matched normal subjects. Cognitive function was assessed by a short battery of neuropsychologic (NP) tests, and the two groups of MS patients were selected on the basis of substantial non-overlapping degrees of cognitive deficit in the demented as compared to the non-demented group. The N100, P200 and P300 ERP components were longer in latency in the demented patients, and the N100-P300 interval was prolonged as well, compared to the non-demented patients, whose ERP latencies did not differ from those of the normal subjects. Increased P300 latency was associated with poorer performance on the NP tests, especially those sensitive to impairment of learning and retrieval from memory. The reaction times of both patient groups were prolonged as compared to the controls, whereas the accuracy of the demented patients was significantly poorer than that of the non-demented patients.

Adult↗
PubMed1991

High-dose oral baclofen: experience in patients with multiple sclerosis.

We reviewed a 10% random sample of charts from an outpatient clinic for multiple sclerosis to determine the frequency with which baclofen was prescribed for spasticity in high doses (greater than 80 mg/d). About 20% of patients had taken high-dose baclofen, and 15% were still receiving a high dose. Taking a high dose was not associated with discontinuing treatment.

Administration, Oral↗
PubMed1987

Trimodal evoked potentials compared with magnetic resonance imaging in the diagnosis of multiple sclerosis.

Twenty-three patients with the clinical diagnosis of possible multiple sclerosis (MS) were tested with magnetic resonance imaging (MRI) and trimodal evoked potentials. Fourteen patients showed abnormalities on both MRI scans and at least one evoked potential modality (65%). Four patients had normal MRI scans but at least one abnormality on evoked potential testing (17%). One patient had normal triple evoked potentials with an abnormal MRI result. Four patients had normal results on both MRI and triple evoked potential testing; two of these patients were later found to have immunologic abnormalities in the cerebrospinal fluid consistent with the diagnosis of MS. Combined evoked potential testing was found to have a higher sensitivity than MRI in confirming a diagnosis of MS. Three patients with the clinical diagnosis of definite MS were also tested. All these patients showed abnormalities on evoked potential testing, although one patient had a normal MRI result. Of all 26 patients who were studied, 17 showed abnormal MRI results and 21 showed at least one abnormality on evoked potential testing.

Adult↗
PubMed1984

Radioisotope studies of neurogenic bladder in multiple sclerosis.

Urinary dysfunction is a frequent and often serious manifestation of multiple sclerosis. If ignored, urinary tract pathology can cause disabling symptoms and life-threatening complications. Symptomatic relief and preventative measures are available once the underlying neurogenic pathology has been identified. The conceptualization of the categories "Failure to Store," "Failure to Empty," or "Combined" provide practical diagnostic and treatment catagories. One important diagnostic test to help define treatment parameters is the radioisotope renal/residual urine study.

Adult↗
PubMedDate not supplied

The utility of visual evoked potentials using hemifield stimulation and several check sizes in the evaluation of suspected multiple sclerosis.

One hundred and eleven patients with suspected multiple sclerosis (64 possible, 47 probable) and 16 with a definite diagnosis of MS were evaluated with pattern-reversal visual evoked potentials (VEPs), employing monocular full-field checks subtending 7', 14' and 28' of visual angle, and right and left hemifield 28' checks. Thirty-seven patients (29%) had a completely normal study. Sixty-six patients (52%) had abnormal responses to full-field 28' checks, and in 13 (10%) of these, additional abnormalities were found in one or more of the other test conditions, which indicated the presence of an additional site of dysfunction in the visual pathway. Twenty-four patients (19%) with 'normal' full-field 28' responses had abnormalities in one or more of the other test conditions; these included prolonged latency to small size (7' and 14') full-field checks, abnormal responses in homonymous hemifields, and abnormal responses limited to a hemifield of one eye. Thus, the use of several check sizes and hemifield stimulation not only increases the sensitivity of VEPs in the evaluation of patients with suspected demyelinating disease, but enhances the capability of the VEP to demonstrate more than one area of visual system impairment.

Adolescent↗