Clinical ratings: relationship to objective psychometric assessment in individuals with dementia.
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Aged↗
Biomedical subjects
R I Block
Publications and source records attributed to R I Block.
Alprazolam and lorazepam effects on memory acquisition and retrieval processes.
A double-blind study involving healthy young adult males examined acute effects of two benzodiazepines (alprazolam 1 mg and lorazepam 2 mg) on long-term memory acquisition and retrieval, using Buschke's "selective reminding" task and a free recall task. Subjects learned lists consisting of high and low imagery nouns. The assessments, done at baseline and hourly for 4 hours after drug ingestion, also included two psychomotor tests and subjective ratings by subjects. Both benzodiazepines produced marked memory impairment. Contrary to the prevailing view that benzodiazepines primarily impair long-term memory acquisition rather than retrieval, results from Buschke's task indicated impairment of retrieval as well. This finding may be related to the procedures and assumptions of Buschke's task. The benzodiazepine-induced impairments increased over the course of successive trials on the same list. Both drugs decreased the normal superiority in recall of high imagery words relative to low imagery words, impaired psychomotor performance, and increased subjective sedation. Alprazolam and lorazepam produced equally intense impairments. Alprazolam tended to produce earlier impairment and earlier recovery.
Adult↗
Marijuana effects on visual imagery in a paired-associate task.
Marijuana effects on visual imagery, examined using a paired-associate learning task, differed from expectations based on previous subjective reports that marijuana enhances visual imagery. Subjects (48 men, mean age 22.4 yr.) were assigned to four groups (12 subjects per group) differing in (a) whether or not they received specific instructions to use imagery to facilitate learning and (b) whether they received marijuana or placebo. Imagery instructions improved recall, but marijuana did not influence the amount of this improvement. After the memory tests, subjects instructed to use imagery described their images. Marijuana decreased the rated vividness of these imagery descriptions.
Adult↗
Marijuana effects on semantic memory: verification of common and uncommon category members.
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Adult↗
Use of computerized psychomotor testing in determining CNS effects of drugs.
Two interactive, computer-controlled tests--critical flicker fusion and discriminant reaction time tasks--are described. These tasks, and subjective sedation ratings using visual analogue scales, were shown to be sensitive in a dose-related fashion to the effects of CNS depressants (diazepam, 15 mg and lorazepam, 1 and 2 mg). Such brief, interactive, computerized tasks should be useful in screening new agents for CNS activity in humans.
Adult↗
Memory performance in individuals with primary degenerative dementia: its similarity to diazepam-induced impairments.
Impairments of memory storage and retrieval produced by diazepam (2.5 mg, 5 mg, and 10 mg) in normal elderly individuals were compared to those observed in patients with primary degenerative dementia tested under nondrug conditions. The highest diazepam dose affected retrieval as well as storage processes in Buschke's "selective reminding" task, producing impairments qualitatively similar to those shown by demented patients. All diazepam doses impaired Buschke task performance in the normal elderly individuals; normal young subjects, in contrast, showed no impairment with a low (2.5 mg) diazepam dose.
Adult↗
Psychedelic effects of a subanesthetic concentration of nitrous oxide.
The subjective effects of nitrous oxide were examined by administering questionnaires to volunteers (16 men and 16 women) breathing 30% nitrous oxide or 100% oxygen. Nitrous oxide produced a variety of subjective effects, including some that are characteristic of psychedelic drugs, such as happy, euphoric mood changes, changes in body awareness and image, alterations of time perception, and experiences of a dreamy, detached reverie state. The subjective effects, including those of a psychedelic nature, were very similar to the subject effects we observed in a previous study of nitrous oxide. However, euphoric mood changes were more pronounced, and adverse effects were less pronounced, in the present study, possibly due to the shorter duration of gas inhalation or the minimal tests of performance involved. Some other differences in subjective effects between the present and previous studies were identified by a discriminant analysis and seemed related to specific differences in experimental conditions. This suggests that the environment can influence which drug effects emerge, or at least their relative prominence. Clinicians should be familiar with the range of subjective effects that patients inhaling nitrous oxide may experience.
Adult↗