Related Experiment Video
Updated: Oct 19, 2026

An Automated System for Sound Localization Testing in Hearing-Impaired Listeners
Published on: March 13, 2026
Background sound pressure fluctuations (5 DB) from overhead ventilation systems increase subjective fatigue of
M A Persinger1, S G Tiller, S A Koren
1Department of Psychology, Laurentian University, Sudbury, Ontario, Canada.
Abstract:
During each of four successive sessions (once per week), 21 university students attended 3-hr. lectures. During alternative weeks the fans of the room's ventilation system were either on or off. When operating, they generated an average sound pressure that varied continuously between 60 and 65 dB. The dominant frequency of this 5-dB amplitude modulation of sound pressure was within the electroencephalographic range (5 Hz to 25 Hz). At the end of each hour of the lecture for each session each student estimated on 7-point summated rating scales fatigue (none to maximum) and concentration (poor to excellent). As a group, the students reported more fatigue during lectures when the fans were operating relative to lectures when the fans were not operating. This environmental effect explained about 30% of the variance in fatigue ratings and may be sufficient to affect adversely the attention of students within these settings.
Related Concept Videos
Sound Intensity Level
The human ear can perceive an extensive range of sound intensity, necessitating the use of the logarithmic scale to define a physical quantity—the intensity level. It is a ratio of two intensities and hence a...
Intensity and Pressure of Sound Waves
Unlike the time average of a sinusoidal term, which is zero since it is positive and...
Sound Intensity
Perception of Sound Waves
The pitch of a sound depends on the frequency and the pressure amplitude of the source. Two sounds of the same frequency...
Respiratory System Abnormal Finding II: Palpation and Auscultation
Palpation Findings
During a respiratory assessment, palpation can reveal several vital abnormalities:
Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
