Event-related potential in Alzheimer disease.

Auditory event - related potentials were studied in 20 patients with SDAT and 20 age and sex matched normal controls. Patients with SDAT showed prolonged latencies of N200 and P300 components. The mean amplitudes of N200 and P300 were lower in the SDAT group. This reflects the impairment of the speed of neural processing in patients with SDAT. There were no significant correlations of the progression of P300 latencies from mild to severe dementia according to global dementia scales.

Classification of dementia patients by a WAIS profile related to central cholinergic deficiencies.

Sixty-two patients were classified as having Alzheimer-type dementia (AD) or multi-infarct dementia (MID) on the basis of clinical criteria. Protocols from the Wechsler Adult Intelligence Scale (WAIS) were scored according to a formula reported by Fuld to reflect the effects of scopolamine administration in young adults. The formula correctly classified 13 of 23 AD patients and 37 of 39 MID patients. The formula was similar to Wechsler's deterioration quotient, which produced a greater number of false positives. The formula did not appear to be biased by age, sex, or severity of impairments. Results suggest that the neuropsychological investigation of AD which emphasizes the deficiencies in cholinergic neurotransmission may be a fruitful avenue of further investigation.

Proline in the cerebrospinal fluid of normal subjects and Alzheimer's-disease patients, as determined with a new double-labeling assay technique.

Past studies have implicated proline involvement in the function of memory and learning. A new micromethod has been developed that is suitable for measuring proline accurately in as little as 0.1 ml of CSF. In normal human CSF, the average proline level was found to be consistently about 1.3 microM. In the CSF of patients with Alzheimer's disease and mixed dementias, the levels of proline showed no statistically significant difference from proline levels in the CSF of normal controls. Furthermore, the proline levels in the CSF of the Alzheimer's disease patients did not reflect, consistently, the cognitive deficits or the symptomatic severity of the disease. Proline levels in CSF showed no statistically significant change with the age of individuals tested.

Neuropsychological impairment after carotid endarterectomy correlates with intraoperative ischemia.

Detailed neuropsychological assessments were performed before and shortly after carotid endarterectomy in thirty-four patients. The degree of intraoperative ischemia was assessed by monitoring the somatosensory evoked cortical potential change upon carotid clamping. Changed neuropsychological performance was found to be related to intraoperative ischemia most clearly in patients with a history of previous stroke and in those with more severe vascular disease. In such patients greater SSEP change was correlated with greater neuropsychological change postoperatively.

Neuropsychological performance one week after carotid endarterectomy reflects intra-operative ischemia.

Fourteen patients with severe bilateral carotid artery stenosis underwent carotid endarterectomy. Intra-operative ischemia was monitored by somatosensory evoked potentials (SSEP) bilaterally. Neuropsychological evaluations were completed within two days before operation and 4-9 days after operation. Complete loss of N1-P1 or P1-N2 components of the SSEP (seen in 4 patients) was associated with a worsening of neuropsychological abilities (p less than .01). Two of these patients subsequently had strokes (7 and 35 days after operation). No other patients in the series have had strokes. Patients whose N1-P1 or P1-N2 amplitudes decreased by 50% or more performed worse after operation than patients with less severe reductions in these amplitudes (p less than .02). Time since first ischemic symptoms, age, education, clamp time, pre-operative stroke, and interval from surgery to assessment were not statistically related to changes in neuropsychological abilities. Patients with ischemic events in the week prior to surgery tended to improve in neuropsychological abilities 4-9 days after operation (p less than .05). Recentness of ischemic episode, however, was not related to intra-operative SSEP change. Results suggest the potential utility of intra-operative SSEP monitoring and early post-operative neuropsychological assessments both for clinical and research purposes.

Lithium-induced increases in red blood cell choline and memory performance in Alzheimer-type dementia.

To investigate the relationship between RBC choline and memory in Alzheimer-type senile dementia (SDAT), lithium carbonate was administered to 14 SDAT patients in doses of 400-600 mg/day for 5 weeks. A battery of memory tests was administered at baseline and at weekly intervals. Five patients with serum concentrations below 0.6 meq/liter developed neurotoxicity and were dropped from further analysis. For the remaining patients, Li+ with mean serum concentrations up to 0.6 meq/liter did not alter memory scores significantly. The dramatic increases in RBC choline during the study, however, suggest that RBC choline is not correlated with memory functioning in SDAT.

Changes in brain ventricular size with repeated CAT scans in suspected Alzheimer's disease.

The interpretation of brain ventricular size in CAT scans of patients with dementia is made difficult by the marked variability in ventricular size that occurs with normal aging. Five patients with probable Alzheimer's disease had serial CAT scans. Published normative data were interpolated to estimate the normal rate of change in ventricular size. Over a period of 15 to 35 months, four of the five patients had increases in ventricular size that were remarkably greater than the norms. The data suggest that the rate of change in ventricular size may be of considerable interest in longitudinal analyses and as a neurodiagnostic parameter.

Russell's revised Wechsler Memory Scale in the evaluation of dementia.

Matched 31 elderly normals and 25 patients with suspected Alzheimer's disease for age and education and administered the Revised Wechsler Memory Scale (WMS-R). The patient group performed significantly less well than the control group on all WMS-R subtests. A bimodal distribution of Percent Retained scores was noted in the patient group, but not in the control group. Results are discussed with respect to the clinical utility of the WMS-R as a memory screening procedure.

Long-latency somatosensory evoked potentials during carotid endarterectomy.

Scalp recorded somatosensory evoked cortical responses (SSEP) may be measured under general anesthesia to assess the electrical responsiveness of the brain. Such potentials were measured in 25 patients undergoing carotid endarterectomy without shunt. Electrical unresponsiveness occurred bilaterally in one patient and unilaterally in one patient. The patient with unilateral electrical silence developed a perioperative stroke, the only stroke in this series. Analysis of the SSEPs recorded from these patients suggests that profound ischemia produces electrical silence: that intermediate degrees of ischemia produce prolonged interpeak latencies and decreasing amplitudes in the SSEP. This modality seems to offer promise as an intraoperative monitor during cerebrovascular surgery.

Cognitive improvement after extracranial reconstruction for the low flow--endangered brain.

Twelve patients with multiple occlusive neck vessel lesions were thought to possess low flow-endangered brains. These patients were studied before and after carotid reconstruction with a battery of neuropsychologic tests emphasizing memory and mental agility. A closely matched control group was selected from patients undergoing endarterectomy for hemodynamically insignificant lesions. The patients with low flow-endangered brains showed significantly greater improvements in memory and mental abilities than did the control group. Reconstruction of neck vessels may reverse such global neurologic deficits in carefully selected patients.

Measurement of cholinergic drug effects on memory in Alzheimer's disease.

Double-blind, placebo-controlled investigations of scopolamine, physostigmine, arecoline, and tetrahydroaminoacridine (THA) in normal adults and in dementia of the Alzheimer-type (DAT) were reviewed to determine the relative sensitivity of various assessment procedures in the measurement of drug effects. In normal adults, word list learning techniques have been most widely employed and have been sensitive to drug effects. In DAT, a wide variety of assessment procedures have been employed. Based on the limited number of possible comparisons across studies, two procedures appear to be useful: word list learning tasks that generate an index of intrusion errors, and visual recognition tasks. The lack of standardized assessments limits the ability of investigators to replicate studies, to compare relative efficacy of various drugs, or to address a number of other questions that are fundamental to the development of effective cholinergic treatments for DAT.

Lecithin and memory training in suspected Alzheimer's disease.

Ten patients diagnosed clinically as having Alzheimer's disease (age range 54 to 73 years) were given 35 g/day of a 53% lecithin mixture for two weeks, in a double-blind crossover design. Patients received memory training during the lecithin condition and "placebo training" during the placebo drug condition. Repeated assessment with Buschke's Selective Reminding Procedure provided no evidence of a therapeutic lecithin effect either during the two week clinical trial or during longer follow-up trials. Noninvasive measurement of regional cerebral blood flow (nr CBF) by the 133Xe-inhalation method, and repeated EEG's also failed to demonstrate a therapeutic effect. These latter indices reflected a decline in cerebral function over the course of the study, a finding which paralleled clinical impressions in four of the patients. Follow-up trials of memory training under placebo and lecithin conditions provided some suggestion that memory training may lead to some immediate improvement in list-learning ability, but the improvement was not well maintained overtime.

Quantitative indexes of computed tomography in dementia and normal aging.

Quantitative indexes of compute tomography were compared in 28 patients with Alzheimer dementia and in 30 elderly persons with no history of neurologic disease. Age-corrected ventricle-brain ratios were abnormal for half of the dementia patients, whereas only a single subject in the control group had ventricles outside the limits of normal variation. Measurement of the distance between the third ventricle and Sylvian fissure indicated that the dementia patients had significantly more atrophy in this area. Employment of quantitative indexes standardized for age may aid in differentiating cerebral atrophy associated with dementia from that associated with normal aging.