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A C Coats

Publications and source records attributed to A C Coats.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

Computer-quantified positional nystagmus in normals.

INTRODUCTION: Most current authorities agree that, in the absence of visual fixation, low intensity nystagmus can be recorded by electronystagmography (ENG) in clinically normal people. However, there are some notable dissenters, and the reported incidence, intensity, and direction of "normal" spontaneous/positional (S/P) nystagmus vary widely across laboratories. The highly subjective element introduced by manual interpretation of position test records compounds the problem of characterizing "normal" S/P nystagmus. MATERIALS AND METHODS: A computerized ENG analysis system which removes this element of subjectivity is described, and results of a study validating its results against those of experienced ENG interpreters are reported. RESULTS: The computer found an S/P nystagmus behind closed eyelids in at least one of five test positions in 42 of 51 clinically normal subjects (82.3%). This "normal" S/P nystagmus had a statistically significant overall directional bias toward left beating, but was affected by position--tending toward right beating in the left lateral position. The upper 95.4% confidence limits for computer-measured slow phase velocities of "normal" S/P nystagmus were -5.5 degrees/sec (left beating) and +4.4 degrees/sec (right beating). CONCLUSION: Possible explanations for "normal" S/P nystagmus include clinically undetected pathology, normal asymmetries in the vestibulo-ocular reflex, and an imprinted oculomotor pattern such as might be created by reading.

Adolescent↗
PubMedDate not supplied

Otoacoustic emissions in ears with hearing loss.

Fifty ears of 37 patients demonstrating several common types of hearing impairment were examined for the presence of spontaneous and evoked otoacoustic emissions to investigate the relationship of acoustic emissions to hearing pathology. Of the 50 ears, 44 exhibited various degrees of sensorineural hearing loss. Evoked otoacoustic emissions to clicks were detected in 34 of 35 sensorineural hearing loss ears with a subjective click threshold less than 55 dB SPL (25 dB nHL). None of nine ears with sensorineural hearing impairment and a subjective click threshold greater than 55 dB SPL demonstrated click-evoked emissions. Spectral analyses revealed that the constituent frequency components of evoked emissions were always within the frequency range where audiometric thresholds were less than 35 dB HL, and in the majority (94%) of cases, thresholds were less than 25 dB HL. In ears with relatively well-preserved hearing within the frequency range of click or 1.5-kHz toneburst stimuli, the basic features of evoked emissions were similar to those described for normal ears. Similarly, for ears demonstrating spontaneous otoacoustic emissions, estimated audiometric thresholds at the emitted frequencies were always less than 20 dB HL. The influence of the type of otologic pathology on acoustic emissions was studied in a subset of ears exhibiting typical high-frequency hearing losses. Ears with a noise-induced impairment showed a significant reduction in the incidence of both spontaneous emissions and spectral peaks in evoked emissions that was not evident in ears with similar patterns of hearing loss caused by other factors.

Acoustic Stimulation↗