Touchscreen Smartphone Interaction in Parkinson's Disease and Healthy Subjects in Outpatient Clinics

We read with interest the article by De Vleeschhauwer et al1 about touchscreen skills in patients with Parkinson’s disease (PD). We acknowledge that this pioneer and exhaustive effort highlights precisely some of the main difficulties that these patients encounter while interacting with touchscreen devices. One of these examples is the prolonged duration of the sliding tasks performed by the patients. The article reveals that the patients’ accuracy and their intertap interval is similar to those shown by participants without PD. We achieved comparable results in previous research. In previous research, we designed a pilot study focusing on routine outpatient clinics by a trial with a prototype smartphone application (previously used by patients with essential tremor).2 A total of 18 patients with PD and 22 controls matched by age and sex (Table 1) were recruited. They performed 5 repetitions of 4 simple tests that were designed to be common touchscreen activities when using smartphones (further methodological details can be found in Supplementary Material S1). Despite the different methodologies and devices used, both studies shared small sample sizes and easy reaching, sliding, and tapping tasks. In both studies, patients with PD achieved similar accuracy and a similar intertap interval time (Table 1) to healthy participants. In contrast to De Vleeschhauwer et al, we did not find significant differences in the duration test performance between patients with PD and controls. This could be explained by the limited statistical power, more recent onset of the disease, the milder severity of our patients, and fewer repetitions of the tasks and the fact that the most complex sliding tasks were not performed. In addition, there were differences in the touchscreen interface settings3 concerning the type of device, software, button size, and the double-tapping act. We consider that the approach of De Vleeschhauwer et al dealing with more repetitions of the tasks makes the b