ABSTRACT
It is acknowledged that there is a negative relationship between dementia and auditory function in older adults. This study conducted a systematic review and meta-analysis based on the data of audiologic testings from patients with neurodegenerative diseases in terms of auditory eventrelated potentials and central auditory processing tests, while focusing on Alzheimer’s disease (AD), dementia with Lewy bodies (DLB), and Parkinson’s disease dementia (PDD). A total of 34765 articles were retrieved from the seven electronic databases. After being screened by Participants, Index test, Control, Outcomes, Study design (PICOS) criteria, 129 articles for AD were included and then 72 articles were applied to the meta-analysis. However, five and six ar-ticles were systematically reviewed for the auditory functions of DLB and PDD, respectively,due to a small number of articles. The results of meta-analysis showed a significant difference between patients with AD and age-matched normal subjects, for N200 and P300 latency, P300 amplitude, and the behavioral central auditory processing tests, although there was a high heterogeneity. On the other hand, the systematic review indicated that the results of mismatch negativity test might distinguish auditory performance of DLB patients from that of PDD. Furthermore, for P300 amplitude, anterior to posterior distribution of brain resulted in meaningful difference of auditory function between AD and DLB patients. In sum, current review study suggests that lesion and degree of auditory (dys)function may be different depending on the type of dementia, although future research should be followed.
ABSTRACT
The present study aimed to compare thresholds of directbone-conduction (BC direct) with those of behaviorally measured BC pure-tone audiometry(PTA) and objectively measured BC auditory brainstem response (ABR) to confirm the clinicalfeasibility of their relationships. Subjects and Methods: Young adults with normal hearingparticipated in the study to determine the thresholds from three measurements at four testingfrequencies. In the BC direct, the vibrator of a bone-anchored hearing aid softband wasplaced on the right mastoid of each subject. In both PTA and ABR, a B71 bone oscillatorwas placed on the subject’s right mastoid. While the subject’s thresholds of BC direct andBC PTA were determined with a clinically routine 5-dB step procedure, BC ABR was conductedto determine the individual’s hearing sensitivity by a peak V of the waveform usingtone-burst and click stimuli. Results: The BC direct showed a different pattern between lowand high frequencies. Precisely, its thresholds were 13.25 and 12.25 dB HL at 0.5 and 1kHz, respectively, but 19 and 19.75 dB HL at 2 and 4 kHz, respectively. A significant positivecorrelation existed between BC direct and PTA at 1 kHz, which was also correlated withABR. Conclusions: Based on the current data, the thresholds of BC direct were similar toBC PTA at low frequencies and BC ABR at high frequencies. The thresholds of BC directmight be predictable at approximately 5 dB higher (or lower) than that in PTA, although alarge data set is required for standardization. J Audiol Otol 2020;24(2):85-90