Hearing Loss and Alzheimer Disease.

Several studies have been done to investigate the role of hearing loss (HL) in cognitive decline. A co-existence of these two conditions has been identified. Recently, thanks to the use of functional MRI and EEG it has been shown that untreated HL can expose patients with cognitive decline to a higher risk of developing Alzheimer Disease (AD). This chapter will discuss the difference between central and peripheral HL, the link between HL and cognition and the relationship between HL and AD. At the end of the chapter the available technologies to treat HL will be discussed as well as their impact on memory and cognition.

Persistent COVID-19 parosmia and olfactory loss post olfactory training: randomized clinical trial comparing central and peripheral-acting therapeutics.

PURPOSE: Although COVID-19 anosmia is often transient, patients with persistent olfactory dysfunction (pOD) can experience refractory parosmia and diminished smell. This study evaluated four putative therapies for parosmia in patients with chronic COVID-19 olfactory impairment. METHODS: After screening nasal endoscopy, 85 patients (49 female, 58%) with pOD and treatment-refractory parosmia were randomized to: (1) ultramicronized palmitoylethanolamide and luteolin + olfactory training (OT) (umPEALUT group, n = 17), (2) alpha-lipoic acid + OT (ALA group, n = 21), (3) umPEALUT + ALA + OT (combination group, n = 28), or 4) olfactory training (OT) alone (control group, n = 23). Olfactory function was assessed at baseline (T0) and 6 months (T1) using a parosmia questionnaire and Sniffin' Sticks test of odor threshold, detection, and identification (TDI). Analyses included one-way ANOVA for numeric data and Chi-Square analyses for nominal data on parosmia. RESULTS: The umPEALUT group had the largest improvement in TDI scores (21.8 ± 9.4 to 29.7 ± 7.5) followed by the combination group (19.6 ± 6.29 to 27.5 ± 2.7), both p < 0.01. The control and ALA groups had no significant change. Patients in the combination and umPEALUT groups had significantly improved TDI scores compared to ALA and control groups (p < 0.001). Rates of parosmia resolution after 6 months were reported at 96% for combination, 65% for control, 53% for umPEALUT and 29% for ALA (p < 0.001). All treatment regimens were well-tolerated. CONCLUSIONS: umPEALUT and OT, with or without ALA, was associated with improvement in TDI scores and parosmia, whereas OT alone or OT with ALA were associated with little benefit.

Olfactory Dysfunction, Headache, and Mental Clouding in Adults with Long-COVID-19: What Is the Link between Cognition and Olfaction? A Cross-Sectional Study.

Smell alteration and cognitive impairment are common features of the Long-COVID Syndrome. Mental clouding, often described as brain fog, might affect smell by altering recollection of odors or through a share mechanism of neuroinflammation. We investigated mental clouding, headache, and cognitive function in adult patients with persistent COVID-19 olfactory dysfunction. This multi-center cross-sectional study enrolled 152 adults with self-reported olfactory dysfunction from 3 tertiary centers specialized in COVID-19 olfactory disorders. Inclusion criteria were smell alterations after COVID-19 persisting over 6 months from infection, age >18 and < 65. Exclusion criteria included smell alterations, headache, or memory problems prior to COVID-19 infection. The patients were evaluated by olfactometry, nasal endoscopy, headache scale, cognitive assessment, Mini Mental State Examination (MMSE), and self-reported measures. Smell dysfunction was stratified and classified based on olfactory deficit severity and presence of olfactory distortion (parosmia, cacosmia). Data on smell disorder, mental clouding, MMSE, and headache were analyzed to assess correlations. Among the 152 patients studied, 50 (32.8%) presented with anosmia, 25 (16.4%) with hyposmia, 10 (6.6%) with parosmia/cacosmia, and 58 patients (38.2%) with a combination of hyposmia and parosmia; seven (4.6%) patients suffered from headache exclusively, and two (1.4%) had headache and mental clouding as their primary symptom. Headache was reported by 76 (50%) patients, and mental clouding by 71 (46.7%). The patients reporting headache, mental clouding, or both, had significantly increased risk of suffering from anosmia and/or hyposmia when compared with their counterparts without these neurological symptoms. No patients had reduced MMSE scores. In our cohort of adult patients with post-COVID-19, smell alterations persisting over 6 months, cognitive impairment and headache were associated with more severe olfactory loss, consistent with neuroinflammatory mechanisms mediating a variety of Long-COVID symptoms.

Hearing loss and dementia: radiologic and biomolecular basis of their shared characteristics. A systematic review.

Dementia and hearing loss share radiologic and biologic findings that might explain their coexistence, especially in the elderly population. Brain atrophy has been observed in both conditions, as well as the presence of areas of gliosis. The brain atrophy is usually focal; it is located in the temporal lobe in patients with hearing loss, while it involves different part of brain in patients with dementia. Radiological studies have shown white matter hyperintensities (WMHs) in both conditions. WMHs have been correlated with the inability to correctly understand words in elderly persons with normal auditory thresholds and, the identification of these lesion in brain magnetic resonance imaging studies has been linked with an increased risk of developing cognitive loss. In addition to WMHs, some anatomopathological studies identified the presence of brain gliosis in the elderly's brain. The cause-effect link between hearing loss and dementia is still unknown, despite they might share some common findings. The aim of this systematic review is to analyze radiologic and biomolecular findings that these two conditions might share, identify a common pathological basis, and discuss the effects of hearing aids on prevention and treatment of cognitive decline in elderly patients with hearing loss.

Does Unilateral Hearing Loss Impair Working Memory? An Italian Clinical Study Comparing Patients With and Without Hearing Aids.

Working memory (WM) function can be reduced in patients suffering from unilateral hearing loss (UHL) and can affect their academic performance. We aimed to compare the WM abilities of three categories of children with UHL: patients implanted with hearing aids (HAs), patients receiving a bone-anchored hearing implant (BAHI), and subjects who did not receive hearing devices. A randomized clinical study, in which 45 children (mean age: 9.5 years) were evaluated by pure tone audiometry (to identify the side and the severity of the UHL), was conducted in a tertiary referral center. Patients were simply randomized into three groups: (1) children without HAs (No-HA group), (2) patients with a (digital) HA (HA group), and (3) children with a BAHI (BAHI group). Their working and short-term memories were studied in both noisy and silent conditions at the recruiting time (T0, baseline) and 6 months after (T1) the treatment. Statistical analyses were performed to analyze the variances between T0 and T1 within each group and between the three groups. The No-HA group improved its T1 WM scores in silence (p < 0.01), but not in noise. The HA and BAHI groups showed statistically significant variances of T1 WM in noise (p < 0.01 and p < 0.01, respectively). The HA and BAHI groups did not show statistically significant variances compared to T1. Our results suggest that hearing devices (HA and BAHI) in children with sensorineural UHL (SUHL) can improve WM capacity in noise. We speculate that bilateral hearing capacity might improve the quality of life of this population, especially during everyday activities where noise is present.

The impact of white matter hyperintensities on speech perception.

BACKGROUND: The presence of white matter hyperintensities (WMHs) can impact on normal brain function by altering normal signal transmission and determining different symptoms. AIM: To evaluate the relationship between the presence of brain WMHs and the scores of speech perception test (SPT) in a sample of normal-hearing patients under 70 years of age. MATERIAL AND METHOD: Prospective study. One hundred eleven patients underwent audiological screening with pure tone audiometry (PTA), tympanometry, speech perception testing (SPT), and brain magnetic resonance imaging (MRI). T2 sequences were analyzed to identify the presence of WMH that, if identified, were scored using the Fazekas score. Statistical multiple regression analysis was performed to understand the relationship between PTA and SPT score; the Pearson's and Spearman's tests were used to evaluate the correlation between Fazekas scores and SPT. Chi-square test was used to analyze the difference between gender. RESULTS: The results of PTA were not predictive of the SPT score. A negative statistically significant correlation (Spearman's, p = 0.0001; Pearson's, p < 0.001) was identified between the Fazekas score and the results of SPT. No statistically significant differences were identified in the correlation of WMH and SPT between males and females. CONCLUSION: Multiple WMHs in the brain can worsen word recognition in patients with normal auditory threshold; this may be related to the impact that these lesions have on the memory ability. Spread of lesions into the brain might reduce the brain capacity to remember words, despite the sound is correctly perceived by the ear.