Approved Research

An Investigation of Auditory Processes in Parkinsonism Disorders: Risk factors.

Lay summary

Over 150,000 UK citizens have an incurable age-related brain disorder known as a neurodegenerative Parkinsonism disorder. Parkinson's disease (PD) Progressive Supranuclear Palsy (PSP) and Multiple Systems Atrophy (MSA) are all types of neurodegenerative Parkinsonism disorders. These disorders are incurable; therefore, the identification of factors that increase the likelihood of disorder onset, and the occurrence of specific symptoms is vital.

Hearing loss (HL) increases the likelihood of dementia. This may be due to the abnormal accumulation of highly reactive molecules or alterations in specific proteins, which occurs in dementia, leading to the death of cells within the ear that are needed for hearing. Importantly, both of these processes occur in PD and MSA. However, whilst the accumulation of highly reactive molecules does occur, specific protein function is not altered in PSP. Therefore, HL may increase the likelihood of onset of some, but not all, Parkinsonism disorders.

Many individuals with Parkinsonism disorders experience cognitive difficulties (e.g. memory loss) and depression, however, not all do. HL may cause dementia and depression. Therefore, individuals with Parkinsonism disorders who also have HL may be more likely to experience cognitive decline and depression.

Demographic (e.g. sex and ethnicity) and socioeconomic (e.g. wealth and educational attainment) factors appear to influence the likelihood of onset of PD and the relationship between HL and depression. Therefore, it may be that demographic and socioeconomic factors influence the onset of Parkinsonism disorders and the extent to which HL increases the likelihood of onset of Parkinsonism disorders.

Despite the importance of understanding the relationship between HL and Parkinsonism disorders, no prior research has been conducted in this area. Consequently, we will conduct a large-scale analysis, of UK Biobank data, examining the relationships between HL, Parkinsonism disorders, cognitive function, depression and demographic and socioeconomic factors. This will take approximately 3 years.

This project has societal implications. Specifically, following current HL management policy individuals with dementia are classified as at risk of HL and receive more frequent audiology assessments. Thus, evidence that HL influences Parkinsonism disorders onset and symptoms would suggest that individuals with these disorders should also be categorised as at risk and receive more frequent hearing assessments. Additionally, the management of HL reduces cognitive function and depressive symptoms. Therefore, if HL influences cognitive impairment and depression in Parkinsonism disorders, then HL management may be beneficial in the management of these symptoms within these disorders. Thus these findings may instigate clinical trials.