Monitoring the Motor Phenotype in Huntington's Disease by Analysis of Keyboard Typing During Real Life Computer Use

Besides cognitive and psychiatric abnormalities, motor symptoms are the most prominent in Huntington's disease. The manifest disease is preceded by a prodromal phase with subtle changes such as fine motor disturbances or concentration problems.

Movement disorders show a high variation in their clinical manifestation depending on condition and external influences. Therefore, devices for continuous measurements, which patients use in their daily life and which can monitor motor abnormalities, in addition to the medical examination, might be useful. The aim of current scientific efforts is to find markers that reflect the prodromal phase in gene carriers. This is important for future interventional studies, as future therapies should be applied at the stage of neuronal dysfunction, i.e., before the clinical manifestation.

We performed a software-supported, continuous monitoring of keyboard typing on the participants' own computer to evaluate this method as a tool to assess the motor phenotype in HD. We included 40 participants and obtained sufficient data from 25 participants, 12 of whom were manifest HD patients, 7 HD gene expansion carriers (HDGEC) and 6 healthy controls.

In a cross-sectional analysis we found statistically significant higher typing inconsistency in HD patients compared to controls. Typing inconsistency compared between HDGEC and healthy controls showed a trend to higher inconsistency levels in HDGEC. We found correlations between typing cadence and clinical scores: the UHDRS finger tapping item, the composite UHDRS and the CAP score.

The typing cadence inconsistency is an appropriate marker to evaluate fine motor skills of HD patients and HDGEC and is correlated to established clinical measurements.