Evaluation of central auditory processing and investigation of the effects of auditory rehabilitation in early demantia of alzheimer type patients

Objective: The aim of our study is to evaluate the Central Auditory Processing (CAP) skills of individuals with Alzheimer's Type Dementia (ATD) and to investigate the effects of auditory training and auditory rehabilitation (AR) on these individuals' CAP skills and neuropsychological assessment results. Method: Our study group consists of 21 patients aged 65 and over (73.3 ± 6.9 years) diagnosed with ATD. To demonstrate the effect of AR, the individuals included in the study group were divided into two groups under the headings of Group 1 (n=11) who received AR and Group 2 (n=10) who did not receive AR. A Control Group of 10 healthy adults was formed. Our study was designed as a randomized controlled single-blind experimental study. A pretest/posttest control group model was used. The CAP skills and neuropsychological evaluations of Group 1 and Group 2 were examined and compared with the control group aged 65 and over who did not undergo any application. To examine CAP skills, the Mismatch Negativity (MMN), Random Gap Detection Test (RGDT), Frequency Pattern (FP) and Duration Pattern (DP) tests, and the Turkish Matrix Test (TMT) were used. For neuropsychological evaluation, the General Informationnand Orientation, Mental Control Backward One-by-One number (MC-N) and Day (MC-D), Forward (FDST) and Backward (BDST) Digit Span subtests of the Wechsler Memory Scale-Revised (WMS-R), Benton Visual Retention Test (BVRT), Benton Facial Recognition Test (BFRT), Boston Naming Test (BNT), Öktem Verbal Memory Processes Test (Öktem VMPT), and Geriatric Depression Scale (GDS) were used. Results: When the groups were compared with each other in terms of CAP skills before AR, MMN left and right ear latency values, TMT and RGDT values were found to be higher in Group 1 and Group 2 compared to the control group (p=0.002, p=0.001, p=0.032, and p<0.001, respectively); FP and DP values were found to be lower in Group 1 and Group 2 compared to the control group (p<0.001 and p<0.001, respectively). When the groups were compared in terms of pretest/posttest score changes, Group 2 responses who did not receive AR showed, compared to Group 1 responses, an increase in MMN latency change for the left and right ears (p=0.045, p=0.083), a decrease in amplitude change (p=0.032, p=0.024); a worsening of signal/noise thresholds in TMT, FP and DP percentages, and RGDT thresholds (p<0.001, p<0.001, p=0.001, p<0.001, respectively), and a decrease in Current (p=0.034), MC-N (p=0.943), MC-D (p=0.409), FDST (p=0.001), BDST (p=0.897), BVRT (p=0.006), BNT (p<0.001), BFRT (p=0.024), Öktem VMPT Immediate Memory (p=0.125), Total Learning (p=0.008), Highest Learning (p=0.167), Total Recall (p=0.240) scores, with an increase in Learning Mistake (p=0.447), False Recall (p=0.778), False Recognition (p=0.132), GDS (p=0.073) scores. Conclusion: Our study shows that CAP skills are worse in ATD patients compared to normals.