Abstract
The purpose of this paper is to describe analytic data regarding cognitive errors observed in aphasic patients and normal adults subjected to a cognition test of environmental sounds.
Twenty familiar environmental sounds were selected for the present study, including calling or singing of birds, chirping of insects, the sound of footsteps, vehicular noises, noises produced in a kitchen, barking, mewing, clucking, etc. These sounds and noises were recorded on magnetic tape and played back on a tape recorder. The subjects were 40 aphasic patients ranging from 30 to 60 years of age and 50 normal adults ranging from 20 to 60 years of age.
Two experiments were designed to explore factors influencing cognitive function in both groups :
1) The subjects were asked to answer orally or manually the name of the test materials presented through a loud-speaker at a comfortable level.
2) The subjects were asked to point to the picture corresponding to the test sound, from four pictures on a sheet.
Cognitive errors collected from the two groups were analyzed in terms of acoustics, distinctive feature theory and semantics. Latencies from beginning of stimulation to response were measured and compared between the two groups. The results obtained suggested :
1) Misunderstanding or cognitive errors in the normal group may be caused by poverty of distinctive sound features, lack of knowledge of relevant signals or difference in familiarity among generations.
2) In addition, in the aphasic groups some errors, including failure to respond, may be attributed to disturbance at the semantic level.
3) Comparison of latencies may provide information on disturbances of auditory cognitive processing.
