The effects of experimentally induced respiratory virus infections on performance

Abstract

SynopsisStudies of experimentally induced respiratory infections and illnesses showed that influenza impaired performance on a visual search task but had no effect on a simple motor task, whereas colds impaired the motor task but not the search task. The effect of influenza on the search task was observed in both volunteers with significant clinical symptoms and volunteers who were shown, by virological techniques, to be infected but who had no significant clinical illness. Performance was also impaired during the incubation period of this illness, which confirms that subclinical influenza virus infections can have behavioural effects. In contrast to influenza, the effects of colds were restricted to volunteers who had significant clinical symptoms, and the impairments in performance were observed only when the symptoms were apparent.

Selective Effects of Colds and Influenza on Human Performance Efficiency: A Critical Appraisal

“…As Smith et al [ 12] state, there were restrictions placed on the types of performance data obtained, as they had to be collected during trials that had other specific aims. Performance measures were taken before challenge and during the clin ical phase, but in some studies they were also taken in the incubation period [9] as well as in convalescence [12], Because of possible diurnal variation in performance, individuals always repeated the tasks at the same time as they had done previously.…”

“…Inspection of table 3 reveals an incomplete matrix of performance data; not all tasks have been used with all virus types. Thus, the gener alised assertion of Smith et al [9,12] that infection with a cold virus affects hand-eye co-ordination, whereas in fluenza infection does not, may be premature. Closer inspection reveals that the putative dissociation, i.e.…”

“…Closer inspection reveals that the putative dissociation, i.e. be tween the performance effects of colds and influenza, is based upon one type (B) of influenza virus failing to show a performance impairment on either the peg-board [9] or the tracking task [10], the latter being based upon a sam ple of 3 subjects. Furthermore, this is compared with some, but not all, of the cold virus infections leading to impairments on these types of task.…”

“…From these studies, it was concluded that influenza and colds have selective effects on performance [7][8][9], Influenza infection was said to slow reactions to stimuli appearing at irregular intervals or in unknown locations, whereas colds impaired hand-eye co-ordination [7,9], In addition, it was argued that the dissociation of perfor mance deficits produced by cold versus influenza infec tion was of theoretical interest, and possible physiological and molecular mechanisms were proposed [10], At first sight, the CCU data provide the most convinc ing evidence for performance impairments associated with colds and influenza. Indeed, such findings gave the impetus for a study that was recently conducted investi gating the effects of naturally occurring colds on perfor mance efficiency [unpublished data].…”

The Common Cold -- My Favourite Infection: The Eighteenth Marjory Stephenson Memorial Lecture

“…A series of experiments is in progress and only the first few have so far been analysed. However, already, interesting results have emerged (Smith et al, 1987). In the first place he has resolved the dispute between those who believe that people with colds only feel that their performance deteriorates and those that believe that the execution of skilled tasks is objectively worse during a cold or influenza.…”