PubMed Health⌕ Search

Biomedical subjects

H P Stassen

Publications and source records attributed to H P Stassen.

3 recordsLinked to original sources
PubMed1981

Thresholds for the perception of rotation: variability, psychometric curves, and comparison with hearing thresholds.

Psychometric curves were determined for the perception of rotation about a vertical axis. If a logarithmic scale is used, an integrated Gaussian curve gives a reasonable description of the psychometric curve. This curve is characterized by two values: the 50% point, which is defined as the threshold, and the s.d. The s.d. of the vestibular psychometric curve is about 10 dB which is 4 times larger than the s.d. found for the auditory system. The distribution of vestibular thresholds in healthy subjects obtained by Clark and Stewart (1969) is plotted on a logarithmic acceleration scale; it can fitted by a Gaussian function. The s.d. of this function is 5.5 dB, a value which is similar to that found for auditory thresholds. From this it is concluded that the inter-individual variability of the detection threshold for the vestibular system is the same as the inter-individual variability of the detection for the auditory system.

Acoustic Stimulation↗
PubMed1981

The threshold of perception of angular acceleration as a function of duration.

The threshold for rotation about the yaw axis was determined for constant acceleration stimuli as a function of their duration in the range from 3 to 25 s. From the torsion-swing model the following theoretical equation can be derived: alpha thr = C/[1--exp(-ts/tau 1)], where alpha thr = acceleration amplitude at threshold, ts = duration of the acceleration, tau 1 = time constant, C = threshold for very long stimuli. According to this formula the Mulder product (i.e. the product of the threshold acceleration amplitude and the duration of the stimulus) is constant for durations up to 0.3 tau 1. The best fit of this theoretical function to the somatosensory data is found for tau 1 = 14.5 s, and C = 0.220/s2. The time within the Mulder product is constant (about 5 s) is doubtless due to the mechanics of the semicircular canals. For the oculogyral data a lower value of tau 1 is found. We do not have any explanation for this lower value.

Acceleration↗