Speech-in-noise hearing impairment is associated with increased risk of Parkinson's: A UK biobank analysis

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.

To determine whether hearing impairment, estimated using a speech-in-noise test (the Digit Triplet Test, DTT), is a risk factor for Parkinson's incidence.

This was a pre-registered prospective cohort study using data from the UK Biobank. Data pertaining to 159,395 individuals, who underwent DTT testing 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 (95%CI: 1.018, 2.435; P = .041)], indicating 57 % increase in risk for every 10 dB 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.

The congruence of these findings with prior research further supports the existence of a relationship between hearing impairment and Parkinson's incidence.