Nystagmometry: the Art of Measuring Nystagmus Parameters by Digital Signal Processing

Abstract

A method of nystagmus analysis has been developed for clinical and research purposes. Optimum flexibility of analysis is indicated to cope with the problematic signals frequently encountered in pathology. Different modes of analysis may be obtained, varying from fully automatic to step-by-step interactive analysis. Artifact detection and rejection is performed by means of regression analysis with some additional condition tests. The default conditions may be modified or inactivated. A variety of output and display facilities may be used, including permanent storage of adequately labelled retrievable nystagmus data.

Inherited Nonsyndromic Hearing Loss: An Audiovestibular Study in a Large Family With Autosomal Dominant Progressive Hearing Loss Related to DFNA2

“…The methods used, including those of the caloric test and computer analysis, have been described in detail in previ ous reports. [11][12][13][14] Gaze positions were tested to investigate the pres ence of gaze-evoked nystagmus. Saccades, smooth pur suit, and horizontal optokinetic nystagmus responses were elicited and analyzed as reported previously.1 1 3 If the subjects were unable to participate personally, information was obtained by telephone or by hetero anam nesis.…”

Short Nystagmus Duration of Velocity Step Response as an Indicator of Labyrinthine Defects

“…Eye movements were calibrated before each test. The horizontal nystagmic responses, electronically summated over both eyes, were recorded on paper and analog tape and off-line computer analysis of SPV in degrees per second was performed as previously described [4][5][6]. The time constant (T, in s) was derived from a regression line in the plot of log(SPV) of each nystagmus beat versus time after the sudden stop by determining the point in time at which this line passed through the value equivalent to 37% of the (extrapolated) initial SPV [4], For G, or the cumula tive eye displacement which is approximated by the product of ini tial velocity V and time constant T [2,4], the lower 5% confidence limit of 485° [3] was used.…”

Single-Response Variability of Air and Water Caloric Reactions

“…To avoid a learning effect, such as reported by Suter et al (1977), air caloric stimulation was performed by the author most experienced with the method and so was the water caloric stimulation. The method of recording and analysing the post-caloric nystagmus was similar to the computer method described by Huygen (1979). In addition, a programme was included, which allowed for the selection of the culmination phase ( fig.…”