Quantification of Changes in Speech and Motor Function in Huntington's Disease Towards Digital Biomarkers for Disease Management

Huntington’s disease (HD) is a progressive neurodegenerative disease characterised by a triad of motor, cognitive and psychiatric symptoms. It can be diagnosed with a genetic test, however, there is currently no cure or treatment to stop the progression of the disease. Motor symptoms include chorea, dystonia and speech impairment, and vary over the course of the disease. Analysis of acoustic features can provide insights into speech fluctuations, while alterations in surface electromyography (sEMG) features can improve understanding of neural drive and muscle activity. Digital, sensor-based assessments, including speech and sEMG analysis, validated in a HD population, offer the potential to objectively monitor changes in function and assess efficacy of interventions but are not yet available. The aim of the thesis was to characterise changes in speech and upper limb motor function to gain insight into the processes underlying functional impairment in HD and to identify measures that could potentially be used to track symptoms and disease severity. This thesis provides a contribution to the area of speech and movement analysis in HD, offering insights into changes in speech and muscle activity using quantitative methods that have been under-investigated in this population to-date. These can be further developed into biomarkers that can be used to target interventions and aid drug trials in participants with HD. The methods developed for remote monitoring of respiration can similarly provide complementary measures of respiratory function as part of a comprehensive method for digital assessment in HD.