A Placebo‐Controlled Study to Assess the Sensitivity of Finger Tapping to Medication Effects in Parkinson's Disease

Abstract

Background Movement Disorder Society–Unified Parkinson's Rating Scale Part III (MDS‐UPDRS III) is the gold standard for assessing medication effects in patients with Parkinson's disease (PD). However, short and rater‐independent measurements would be ideal for future trials. Objectives To assess the ability of 3 different finger tapping tasks to detect levodopa/carbidopa‐induced changes over time and to determine their correlation and compare their discriminatory power with MDS‐UPDRS III. Methods This was a randomized, double‐blind, crossover study in 20 patients with PD receiving levodopa/carbidopa and placebo capsules after overnight medication withdrawal. Pre‐ and up to 3.5 hours postdose, MDS‐UPDRS III and tapping tasks were performed. Tasks included 2 touchscreen‐based alternate finger tapping tasks (index finger versus index–middle finger tapping) and a thumb–index finger task using a goniometer. Results In the alternate index finger tapping task, levodopa/carbidopa compared with placebo resulted in significantly faster (total taps: 12.5 [95% confidence interval, CI, 6.7–18.2]) and less accurate tapping (total spatial error: 240 mm [95% CI, 123–357 mm]) with improved rhythm (intertap interval standard deviation [SD], −16.3% [95% CI, −29.9% to 0.0%]). In the thumb–index finger task, tapping was significantly faster (mean opening velocity, 151 degree/s [64–237 degree/s]), with a higher mean amplitude (8.4 degrees [3.7–13.0 degrees]) and improved rhythm (intertap interval SD, −46.4% [95% CI, −63.7% to −20.9%]). The speed‐related endpoints showed a moderate‐to‐strong correlation with the MDS‐UPDRS III (r = 0.45–0.70). The effect sizes of total taps and spatial error in the alternate index finger tapping task and opening velocity in the thumb–index finger task were comparable with the MDS‐UPDRS III. In contrast, the MDS‐UPDRS III performed better than the alternate index–middle finger task. Conclusion The alternate index finger and the thumb–index finger tapping tasks provide short, rater‐independent measurements that are sensitive to levodopa/carbidopa effects with a similar effect size as the MDS‐UPDRS III.

Treatment Detection and Movement Disorder Society‐Unified Parkinson's Disease Rating Scale, Part III Estimation Using Finger Tapping Tasks

“…10 Each of the two tasks generated 43 features relating to speed (eg, total number of taps), accuracy (eg, spatial error), rhythm (eg, intertap interval), and fatigue (eg, change in velocity) (Table S1). 10,14 Thumb-Index Finger Tapping A wireless goniometer (Biometrics Ltd, Newport, UK) was placed on the metacarpal and proximal phalanx of the index finger of the most affected hand (if both hands were equally affected, to use their dominant hand). 10,14,30 Each patient was instructed to sit comfortably, hold up the hand, and tap the index finger on the thumb as widely and quickly as possible continuously for 15 seconds.…”

“…10,14 Thumb-Index Finger Tapping A wireless goniometer (Biometrics Ltd, Newport, UK) was placed on the metacarpal and proximal phalanx of the index finger of the most affected hand (if both hands were equally affected, to use their dominant hand). 10,14,30 Each patient was instructed to sit comfortably, hold up the hand, and tap the index finger on the thumb as widely and quickly as possible continuously for 15 seconds. The thumb-index finger tapping (TIFT) assesses unilateral sequential fine finger movements.…”

“…The MDS-UPDRS III classification model was trained on the 90-minute MDS-UPDRS III item scores. 14 The tapping classification models were trained on measurements taken immediately after the MDS-UPDRS III starting at 105 minutes.…”

“…Finger tapping tasks provide insights into fine motor activity 10,11 and have been shown to be quick, effective, and simple assessments for estimating MDS-UPDRS motor disability 12,13 and assessing antiparkinsonian drug effects. [14][15][16][17][18][19] These tasks provide insights into finger and forearm movement speed, accuracy, amplitude, frequency, rhythm, and fatigue. 10,14,20,21 PD patients often experience tremors, stiffness, and difficulty with movement, which can significantly impact their ability to perform daily activities, including buttoning a shirt, typing on a keyboard, or using utensils.…”

“…[14][15][16][17][18][19] These tasks provide insights into finger and forearm movement speed, accuracy, amplitude, frequency, rhythm, and fatigue. 10,14,20,21 PD patients often experience tremors, stiffness, and difficulty with movement, which can significantly impact their ability to perform daily activities, including buttoning a shirt, typing on a keyboard, or using utensils. 22,23 As patients want treatments that will improve their ability to carry out daily activities, measuring motor function through tapping biomarkers can provide a more direct and meaningful assessment of the impact of treatments on patients' lives.…”