Warren L. Danziger

A longitudinal EEG study of mild senile dementia of Alzheimer type: changes at 1 year and at 2.5 years.

This longitudinal study of resting EEGs compared patients with senile dementia of Alzheimer type (SDAT) and healthy controls at 3 times of testing over a 2.5 year period. Measures included the mean EEG frequency as well as the percentage of power in alpha, beta, theta, and delta frequency bands obtained from power spectral analysis. The values from occipital to vertex derivations were averaged for the left and right hemispheres. In healthy older adults delta increased, and both beta and mean frequency decreased over the study period; there was no significant change in theta or alpha. In the SDAT group, all 5 EEG measures changed significantly; there were increases in delta and theta, and decreases in beta, alpha and mean frequency. Theta percentage power distinguished between all 4 stages of dementia (control, mild, moderate and severe). Other EEG measures discriminated only at certain stages. In the mild stage of SDAT theta, beta and mean frequency were already different from control values. In the moderate stage, these differences persisted, and alpha became different. Delta was the last to change, and in the present small sample of those with severe SDAT the difference had not yet reached significance.

Predictive features in mild senile dementia of the Alzheimer type

Forty-three subjects with mild senile dementia of the Alzheimer type, diagnosed and staged by clinical research criteria, were studied with clinical, psychometric, EEG, visual evoked potential, and CT measures. During the 12 months following entry into the study, 21 subjects progressed to moderate or severe dementia, 21 remained mild, and one was lost to follow-up. Many of the clinical and psychometric measures of impairment were predictive of the progression to moderate or severe dementia. Electrophysiologic and CT measures were not. In a discriminant function analysis, the scores on two measures (the digit symbol subtest of the Wechsler Adult Intelligence Scale and an Aphasia Battery) correctly predicted the stage of dementia 1 year later in 95% of the subjects.

Visual evoked potentials in mild senile dementia of alzheimer type

Visual evoked potentials (VEPs) to chessboard shift and to flash stimulation were recorded from 40 subjects with senile dementia of Alzheimer type (SDAT) and 40 individually matched control subjects. All of the SDAT subjects had only a mild degree of dementia and were still living in the community. Analysis of variance showed significant differences between demented and control group means for 3 chessboard shift VEP measures, the demented group having longer latency of peaks P3 and N3, and larger amplitude of segment N2-P3. These three are the earliest reported changes in the VEP in Alzheimer disease, since the flash VEPs showed no measure in which the demented and control group means differed significantly.

Age and the perception of incomplete figures

Three experiments are described. They investigated four possible explanations for the previously reported poorer performance of older adults relative to younger adults in accuracy of identifying incomplete figures: (1) a higher criterion on the part of older adults for producing a response; (2) a lesser familiarity on their part with the stimulus materials; (3) a less adequate knowledge of the information value of particular segments of the figure; (4) a less efficient utilization of partial information. The results of the experiments supported the fourth hypothesis and indicated that older adults are unable to utilize stimulus information as effectively as younger adults in making perceptual inferences.

Birth order and maternal age effect in dementia of the Alzheimer type

Birth order and maternal age were unrelated to dementia of the Alzheimer type (DAT) in a study of 42 probands with clinically diagnosed DAT and 42 age-matched control subjects. Mean birth order in both groups did not differ significantly from the general population. The mean maternal age for the DAT probands was neither significantly different from that for the controls nor from that for the 1920 U.S. Caucasian population. Since the diagnostic criteria for the DAT group were only clinical, an additional 14 probands with DAT confirmed by autopsy were studied. Mean maternal age did not differ significantly in this group from the controls, the general population, or the clinically diagnosed DAT group. It was concluded that maternal age and birth order bear no special relationship to DAT in this sample.

Perception as hypothesis testing

Three experiments were conducted to investigate the previously reported finding that the accuracy of perceptual recognition decreases as the amount of experience with degraded versions of a visual stimulus increases. Since this result is apparently predictable only from the view of perception as an active process of hypothesis generation, this negative-effect-of-prior-experience phenomenon has important implications for theoretical conceptualizations of perception. None of the current experiments yielded any evidence of less accurate perceptual identification with increased number of incomplete versions of the stimuli when accuracy was assessed with a cumulative measure of identification accuracy, but two of the experiments did provide such evidence when accuracy was assessed with a conditional measure of accuracy. Consideration of the complete pattern of results led to the conclusion that there is no real evidence that perception is impaired because of early experience with ambiguous versions of a subject.

Dementia in the elderly: An education model including information, management, and counselling

The number of elderly people in the United States who have dementia is increasing because there are proportionately more older adults in the total population. Because dementia causes progressive deterioration in memory and reasoning, families of individuals with dementia experience emotional, physical, and economic burdens. It is necessary to educate and counsel healthcare professionals and caregivers to assure appropriate care for the patient with Alzheimers disease.

Instrumentality — terminality values in relation to age

Terminal and instrumental value preference was investigated by asking young adults and older adults to respond to a modified version of the Rokeach Value Survey. Terminal and instrumental values were almost identical among the age and sex groups. Thus, the present data provide no evidence to support the hypothesis that older adults have a higher priority for terminal values than do young adults.