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Biomedical subjects

M J Bach

Publications and source records attributed to M J Bach.

6 recordsLinked to original sources
PubMed1976

Effects of trace anaesthetic gases on behavioural performance of volunteers.

Nitrous oxide and halothane, in concentrations as low as 50 p.p.m. and 1.0 p.p.m. respectively, caused measurable decrements in performance in psychological tests in healthy male volunteers. Nitrous oxide alone caused similar effects. The functions apparently most sensitive to these low concentrations of anaesthetic agents were visual perception, immediate memory, and a combination of perception, cognition and motor responses required in a task of divided attention to simultaneous visual and auditory stimuli. These effects were absent in subjects exposed to nitrous oxide 25 p.p.m. and halothane 0.5 p.p.m.

Adult↗
PubMed1976

An audiovisual test of divided attention.

A description is given of an audiovisual reaction time task, performance of which was maximal after 15 min. practice and which lasted at this level for 1 wk. Sensitivity of the test was shown in an adverse effect of inhalation of traces of anesthetic gases. Comparing responses to auditory and visual stimuli, the control auditory reaction times were faster but were lengthened more in the presence of anesthetics than were the visual ones. This test may be useful in other studies of subtle depressant drug effects.

Anesthesia, Inhalation↗
PubMed1975

Psychological studies of human performance as affected by traces of enflurane and nitrous oxide.

Thirty human subjects were exposed for four hours to 500 ppm N-2O and 15 ppm enflurane in air and then, within five minutes, given a 35-minute battery of psychological tests. Performance of a divided-attention audiovisual task and a digit-span memory test were significantly decreased compared with control data following exposure to air. A tachistoscopic task, four tests from the Wechsler memory scale, and five others from the Wechsler Adult Intelligence Scale were unaffected. Thirty subjects exposed to 500 ppm N-2-O in air only scored significantly lower on the digit-span test only.

Anesthesia, Inhalation↗
PubMed1975

The anesthetic effect of air at atmospheric pressure.

Nitrogen has recognized narcotic potential at hyperbaric pressures. No narcotic effect of helium has been demonstrated at any pressure. We evaluated the effect of nitrogen in air at one atmosphere on human performance by comparing it with helium-oxygen using a four-alternative divided-attention task that requires rapid response to auditory and visual signal changes. There was a 9.3 per cent decrease in response time when subjects breathed helium-oxygen, a signigicant change (P less than 0.001). This change could not be ascribed to practice since the order of presentation of gases did not have a significant effect. It concluded that the nitrogen in ambient air slightly but measurable impairs human performance compared with a non-anesthetic gas such as helium.

Air↗