RESUMO
Introduction: Rotatory chair testing has been used to evaluate horizontal canal function. Frequently used tests include sinusoidal harmonic acceleration test (SHAT) and velocity step test (VST). Objectives: Assessment of age effect on the SHAT and VST and assessment of test-retest reliability of the parameters of those two tests. Methods: A prospective study was performed on 100 subjects with no ear or vestibular complaints and normal vestibular evaluation. They were divided into two groups; Group A: below 50 years of age and Group B: 50 years of age or above. SHAT was presented at frequencies 0.02, 0.04, 0.08, 0.16, 0.32, 0.64 Hz with a peak velocity of 60°/s. VST was performed using a maximum velocity of 100°/s with acceleration and deceleration of 200°/s2. Thirty subjects were tested twice to assess reliability. Results: Study participants ranged in age from 20 to 67 years. Regarding group A, the mean age was 30.92 ± 7.31 and 55.36 ± 4.61 for group B. No significant differences were found in SHAT parameters between the two groups. As well, there was no significant difference in VST per-rotatory time constant, however, post-rotatory time constant was significantly longer for Group B (P value < 0.05). Intraclass correlation coefficient (ICC) values showed moderate to good reliability (ICC 0.580-0.818) for SHAT parameters for the lower frequencies and indicated moderate reliability for VST time constant (ICC 0.509-0.652). Conclusions: Age has no significant effect on the parameters of SHAT and VST. Test-retest reliability is generally good for both tests.
RESUMO
INTRODUCTION: There is ample evidence that auditory dysfunction is a common feature of autism spectrum disorder (ASD). Binaural interaction component (BIC) manifests binaural interaction and is valid and proven response which reflects ongoing binaural processing. OBJECTIVES: To investigate the differences in binaural interaction component of auditory brainstem response (ABR-BIC) between children with autism spectrum disorder (ASD) and normal peers and to correlate between ABR-BIC amplitudes and the acquired communication skills in ASD children. METHODS: ASD was diagnosed according to the criteria of 5th edition of diagnostic and statistical manual of mental disorders (DSM-V) and all children with ASD underwent test of acquired communication skills (TACS). Click evoked ABRs were elicited by left monaural, right monaural and binaural stimulation at intensity of 65 dBnHL in all participants. ABR-BIC was then calculated as the difference between the binaurally evoked ABR waveform and a predicted binaural waveform created by algebraically summing the left and right monaurally evoked ABRs. The difference in amplitudes that gives rise to ABR-BIC is at IV-VI waves. RESULTS: ABR-BIC amplitudes were demonstrated to be significantly reduced in the ASD group compared to the control group. There was significant positive correlation between ABR-BIC amplitude and the language and social scores in TACS. CONCLUSION: This study provided an objective evidence of binaural processing disorder in children with ASD.
