ABSTRACT
We are reporting the case of a 41-year-old female diagnosed with a cerebellar astrocytoma. The tumor was detected after the patient was referred for MRI scan because of an abnormal ABR. The ABR was unusual as the I-V interwave intervals (IWIs) were within normal limits bilaterally, but the I-III IWI was prolonged by .40 msec on the left ear in comparison to the right ear. This case report illustrates the importance of the I-III IWI in the detection of retrocochlear pathology and the nonsequential generation of the components of the ABR.
Subject(s)
Astrocytoma/pathology , Cerebellar Neoplasms/pathology , Cerebellum/pathology , Evoked Potentials, Auditory, Brain Stem , Acoustic Stimulation , Adult , Astrocytoma/diagnosis , Astrocytoma/radiotherapy , Audiometry , Brain Stem/diagnostic imaging , Brain Stem/physiopathology , Cerebellar Neoplasms/diagnosis , Cerebellar Neoplasms/radiotherapy , Electronystagmography , Female , Humans , Perceptual Masking , Radiography , Vertigo/diagnosis , Vertigo/physiopathologyABSTRACT
Nystagmic responses to traditional 40-sec, 30 degrees C water calorics were recorded and compared to those obtained with the Brookler-Grams closed-loop irrigator using 30 degrees C, 40-, 50-, and 60-sec irrigations. Significant differences were noted between the responses to the water irrigator and the 40- and 50-sec closed-loop irrigations. The 60-sec closed-loop irrigation produced responses that were equivalent to the responses obtained with the water irrigation in slow component velocity, amplitude, frequency, latency, and duration. The 30 degrees C 60-sec closed-loop irrigation is an acceptable stimulus in electronystagmographic caloric testing.
Subject(s)
Caloric Tests/instrumentation , Electronystagmography/instrumentation , Adolescent , Adult , Caloric Tests/methods , Electronystagmography/methods , Humans , Male , Temperature , Therapeutic Irrigation/instrumentation , Therapeutic Irrigation/methods , Time FactorsABSTRACT
Three types of commercially available caloric irrigation units--air, water, and closed-loop--were evaluated for nystagmus response patterns and comfort. Electronystagmographic recordings were analyzed for slow-phase velocity, response duration, amplitude, frequency, and test-retest reliability. Significant differences were found among the three types of irrigators, between warm and cool irrigators, and between male and female subjects. Test-retest reliability was adequate for all three units. Subjects clearly favored the closed-loop system over the water and air irrigators, but the water irrigator yielded the most robust caloric response.
Subject(s)
Caloric Tests/instrumentation , Adolescent , Adult , Air , Caloric Tests/methods , Data Interpretation, Statistical , Evaluation Studies as Topic , Female , Humans , Male , WaterSubject(s)
Eye Movements , Adolescent , Adult , Age Factors , Aged , Audiology , Electronystagmography , Humans , Male , Middle Aged , Sex FactorsSubject(s)
Caloric Tests/methods , Eye Movements , Vestibular Function Tests/methods , Adolescent , Adult , Cold Temperature , Female , Humans , MaleABSTRACT
Seventy five subjects ranging in age from 18 to 87 years received warm and cool caloric irrigations. Nystagmus was recorded and latency, duration, amplitude, frequency and speed of the slow component were measured. The effects of age, hearing loss, sex and water temperature were evaluated. Significant differences were found in cool water durations. Significant differences were found as a function of age for all parameters in warm water calorics. Response duration was not found to be significantly correlated to speed of the slow component in cool calorics.
Subject(s)
Electronystagmography/methods , Hearing Loss/complications , Nystagmus, Pathologic/diagnosis , Adolescent , Adult , Age Factors , Aged , Child , Cold Temperature , Electronystagmography/instrumentation , Female , Hot Temperature , Humans , Male , Middle Aged , Nystagmus, Pathologic/complications , Sex FactorsABSTRACT
Caloric tests were performed on 20 normal volunteers under the following six conditions of ocular fixation: (1) eyes open with lighted +20-diopter lenses; (2) eyes open with lighted +20-diopter lenses plus strobe lighting; (3) eyes open in darkness; (4) eyes closed in darkness; (5) eyes closed in a dimly lighted room; and (6) eyes open with unlighted +20-diopter lenses plus strobe lighting. Latency, amplitude, frequency, duration, and speed of the slow component were measured from a permanent recording. Significant differences were found between the lighted +20-diopter lens conditions and all others for all variables except latency. Tests performed with lighted +20-diopter lenses should be cautiously interpreted due to the noticeable response suppression noted in these conditions. The present procedure of performing caloric tests with the eyes closed in a dimly lighted room was found to be unqeustionably preferable.
Subject(s)
Caloric Tests/methods , Fixation, Ocular , Vestibular Function Tests/methods , Adult , Female , Humans , Light , MaleABSTRACT
Pure-tone thresholds, speech reception thresholds (SRT), and speech discrimination scores (DS) were obtained by ac and bc on 20 normal-hearing and 30 hearing-impaired adults. Correlations between the SRT and pure-tone thresholds (ave. of .5, 1, and 2 kc/s) were significant by both ac and bc. Correlations between DS by ac and bc were also highly significant, indicating the value of the bc DS in specific difficult cases. The clinical observation was confirmed statistically of decreasing DS with increasing sensorineural hearing loss.
Subject(s)
Audiometry, Speech/methods , Bone Conduction , Hearing Loss, Conductive/diagnosis , Hearing Loss, Sensorineural/diagnosis , Hearing Loss/diagnosis , Adolescent , Adult , Aged , Auditory Threshold/physiology , Evaluation Studies as Topic , Humans , Middle Aged , Speech Discrimination Tests/methods , Speech Reception Threshold Test/methodsABSTRACT
Latency, duration, and amplitude of response, frequency of nystagmic beats, and speed of the slow component of calorically-induced nystagmus were studied by ENG in 14 normal-hearing adults. Attention was directed toward differences as a function of stimulus temperature (30 degrees C vs 44 degrees C) and side of stimulation. Nystagmus amplitudes were significantly larger from R ear as compared to L ear irrigations, and from cool as compared to warm. Ssc's from cool irrigations were also significantly larger than from warm. A series of t-tests computed for correlated samples indicated that the R ear 30 degrees irrigation, which was the first stimulus for all Ss, was responsible for the significant differences. Implications of the need for research on caloric interstimulus intervals and vestibular response fatigue were presented, and a procedure outlined to avoid erroneous results in caloric testing.
