The effect of hearing aids on cognitive function: A systematic review.

RATIONALE: Dementia currently affects 50 million people globally with this expected to triple by 2050. Even though hearing loss is associated with cognitive decline, the underlying mechanisms are not fully understood. Considering hearing loss is the largest modifiable risk factor for developing dementia, it is essential to study the effect of hearing aids on cognitive function. OBJECTIVE: To systematically review the existing literature to examine the evidence for using hearing aids intervention as a treatment for deteriorating cognitive function. DESIGN: A search of PubMed, Cochrane Library, Embase and grey literature was conducted revealing 3060 unique records between 1990-2020. Two reviewers independently selected longitudinal studies observing the effects of hearing aids on cognitive function in persons without dementia at onset of the study. Due to the heterogeneity of the data, a meta-analysis could not be performed. Outcomes are described in a summary of findings table and portrayed diagrammatically. RESULTS: We identified 17 unique studies, spanning 30 years of research and 3526 participants. The included studies made use of 50 different cognitive function tests. These tests were grouped into separate cognitive domains according to the DSM-V classification for further analysis. The most beneficial impact of hearing aids seems to be in the cognitive domain of executive function, with six studies showing improvement, two studies being inconclusive and three studies not demonstrating a significant effect. Three of five studies demonstrated significant improvement when screening for brief mental status. The least beneficial impact is seen in domain of complex attention, with eight studies showing no significant effects, compared with one demonstrating improvement with intervention. CONCLUSIONS: Based on this systematic review, we conclude that there is controversy about the effects of hearing aids on cognition. Additional research through randomized clinical trials with standardized cognitive assessment and longer follow-up is warranted to further elucidate this relationship.

Prognostic role of tumour-associated macrophages and regulatory T cells in EBV-positive and EBV-negative nasopharyngeal carcinoma.

AIMS: Tumour-associated macrophages (TAMs) and regulatory T cells (Tregs) form a special niche supporting tumour progression, and both correlate with worse survival in head and neck cancers. However, the prognostic role of TAM and Tregs in nasopharyngeal carcinoma (NPC) is still unknown. Therefore, we determined differences in TAMs and Tregs in different NPC subtypes, and their prognostic significance. METHODS: Tissue of 91 NPCs was assessed for TAMs and Tregs by determination of CD68, CD163, CD206 and FOXP3 expression in the tumour microenvironment. Clinicopathological correlations were assessed using Pearson X2 test, Fisher's exact test, analysis of variance and Mann-Whitney U test. Survival was analysed using Kaplan-Meier curves and Cox regression. RESULTS: CD68 and FOXP3 counts were higher in Epstein-Barr virus (EBV)-positive NPC, while CD68-/FOXP3-, CD163+/FOXP3- and CD206+/FOXP3- infiltrates were more common in EBV-negative NPC. In the whole NPC group, CD68-/FOXP3- correlated with worse overall survival (OS), and after multivariate analysis high FOXP3 count showed better OS (HR 0.352, 95% CI 0.128 to 0.968). No difference in M2 counts existed between EBV-positive and negative NPC. CONCLUSIONS: FOXP3, a Treg marker, seems to be an independent prognostic factor for better OS in the whole NPC group. Therefore, immune-based therapies targeting Tregs should be carefully evaluated. M2 spectrum macrophages are probably more prominent in EBV-negative NPC with also functional differences compared with EBV-positive NPC.