Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Yasuaki Kawasaki x
  • Refine by Access: All Content x
Clear All Modify Search

Summary

Power spectral analysis and digital filtering of brain stem auditory evoked potentials (baep) were performed in dogs. The baep were recorded in 7 dogs, using alternating clicks at frequency of 20 Hz. The clicks were delivered monaurally at intensity of 90-dB normal hearing level. Power spectral analysis indicated that the frequency compositions of the averaged responses were divisible into 4 frequency bands: A (30 to 390 Hz), B (390 to 680 Hz), C (680 to 910 Hz) and D (910 to 1960 Hz).

The frequency limits of digital high-pass (hp) and low-pass (lp) filters, at which neither peak-to-peak nor absolute amplitudes were reduced, were 1,170 and 1,270 Hz for P1, 290 and 1,170 Hz for P2, 290 and 980 Hz for P3, 290 and 980 Hz for P4, and 200 and 880 Hz for P5, respectively. The dual structure of baep was confirmed in dogs. Below 200 Hz for the hp filter, peak-to-peak and absolute amplitudes of all waves were not significantly reduced. Therefore, this frequency may be a boundary frequency between low- and high-frequency components of baep in dogs. The main source for the high-frequency components that constituted each positive peak and the following trough was derived from frequency bands C and D.

The frequency limits of 200 Hz for a digital hp filter and of 1,270 Hz for a digital lp filter, at which amplitudes of all waves were not reduced, support the analog filter settings recommended for dogs (ie, ≤ 53 and 3,000 Hz for analog hp and lp filters, respectively).

Free access
in American Journal of Veterinary Research

Summary

Effects of analog filter frequency on brain stem auditory-evoked potentials (baep) were investigated in 7 nonsedated dogs. The baep were recorded successively at various low-pass (lp) and high-pass (hp) filter frequency settings. The analog filters had a rolloff of 6 dB/octave.

Decrease of LP filter frequency from 30 kHz to 100 Hz caused prolongation of the peak latency and reduction of the peak-to-peak (from a positive peak to the following trough) and absolute (from a positive peak to the baseline) amplitudes for all peaks, except the peak latency for P5 and the absolute amplitude for P4. Changes in these variables were statistically significant (P < 0.05) at different cutoff frequencies specific for the individual peaks. The interpeak latency between P1 and P4, and P4/P1 peak-to-peak amplitude ratio were not changed significantly. At the lowest (lp filter frequency of 100 Hz, positive peaks (fast waves) seemed to be superimposed on a slow positive wave (slow wave). In contrast, increase of hp filter frequency from 0.53 to 160 Hz did not result in significant changes for any peaks, except for reduction in the absolute amplitude of P4. The various effects of lp filter frequency and negligible effects of hp filter frequency on individual peaks may be attributable to their frequency composition and/or elimination of the slow wave at higher hp filter frequency settings.

On the basis of our results, lp filter setting of 3 kHz and HP filter setting of ≤ 53 Hz are recommended for recording of baep in dogs. These settings sufficiently attenuate unwanted high-frequency artifacts, are adequate for recording of fast and slow waves, and have only slight effects on configurations, peak latencies, and amplitudes.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To elucidate the nature of ataxia observed in 3 cats spanning 2 generations.

Design

Experimental breeding was attempted to confirm heritability of the disease and establish the mode of inheritance; the original 3 cats and their offspring were studied.

Animals

Seven diseased cats spanning 3 generations and 11 neurologically normal cats.

Procedure

Cats were examined by use of the following methods: clinical observation, hematologic and serum biochemical examinations, neurologic examination, electrodiagnostics, magnetic resonance imaging, lysosomal enzyme activity assay, horizontal transmission test, and virologic and pathologic examinations.

Results

All kittens (1 male and 3 females) obtained by backcrosses developed pure cerebellar dysfunction from the age of 7 to 8 weeks onward. It became progressively worse, but not fatal, between 1 and 2.5 months. Prenatal or perinatal infection with feline panleukopenia virus, inherited lysosomal storage diseases, including gangliosidosis and mannosidosis, and feline hereditary neuroaxonal dystrophy were excluded. Magnetic resonance imaging indicated that size of the cerebellum of diseased cats was markedly reduced. Cerebellar cortical degeneration, especially with extensive destruction of Purkinje cells, was observed microscopically.

Conclusion

The disease was concluded to be cerebellar degeneration of a new clinical form in cats having an autosomal recessive mode of inheritance.

Clinical Relevance

When cerebellar dysfunction is diagnosed in a cat, hereditary cerebellar degeneration of this type should be considered in the differential diagnosis.(Am J Vet Res 1996; 57: 296-301)

Free access
in American Journal of Veterinary Research