Hearing Impairment Correlates with Risk of Parkinson's Disease
Hearing loss has been correlated with the risk of numerous forms of neurodegenerative condition. There are many studies similar to the one noted here, correlating degree of hearing loss with risk of Parkinson's disease. While it seems to be the case that hearing loss can accelerate degeneration in the brain, a consequence of reduced input and brain activity in some areas, it is also the case that both hearing loss and neurodegenerative conditions arise from the same underlying forms of cell and tissue damage that drive aging more generally.
Hearing impairment is implicated as a risk factor for Parkinson's disease (Parkinson's) incidence, with evidence suggesting that clinically diagnosed hearing loss increases Parkinson's risk 1.5-1.6 fold over 2-5 years follow up. However, the evidence is not unanimous with additional studies observing that self-reported hearing capabilities do not significantly influence Parkinson's incidence. Thus, additional cohort analyses that draw on alternative auditory measures are required to further corroborate the link between Parkinson's and hearing impairment.
This was a pre-registered prospective cohort study using data from the UK Biobank. Data pertaining to 159,395 individuals, who underwent speech-in-noise testing via the Digit Triplet Test, DTT, and were free from Parkinson's at the point of assessment, were analysed. A Cox Proportional Hazard model, controlling for age, sex and educational attainment was conducted. During a median follow up of 14.24 years, 810 cases of probable Parkinson's were observed. The risk of incident Parkinson's increased with baseline hearing impairment [hazard ratio: 1.57], indicating 57% increase in risk for every 10dB increase in speech-reception threshold (SRT). However, when hearing impairment was categorised in accordance with UK Biobank SRT norms neither 'Insufficient' nor 'Poor' hearing significantly influenced Parkinson's risk compared to 'Normal' hearing.
In conclusion, the congruence of these findings with prior research further supports the existence of a relationship between hearing impairment and Parkinson's incidence.