Smartphone-based app for Carpal tunnel syndrome testing - primary study. (Preprint)

Abstract

Carpal tunnel syndrome (CTS) occurs in as many as 3% of the population. This common condition should be diagnosed earlier because delays in treatment can lead to the loss of some hand functions. Delays are caused in a substantial part by the patients themselves, therefore there is a need to have a screening tool for them – especially in the era of telemedicine. Such a screening tool should have the necessary features: should be easy to use , simple to interpret, universally available and with high sensitivity and specificity values.

To establish the diagnostic value of a new screening tool for CTS – smartphone based tapping test.

The database included each patient who reported himself to the local clinic with suspected CTS. The diagnosis of CTS was made by neurologists based on electrophysiological testing. The Studied population was divided into two groups, positive-CTS and negative-CTS. Patients were asked to perform 60 seconds “tapping” a test on a smartphone-based app. The selected parameters of thumb movements were recorded by the app and compered between each group.

The criteria for inclusion in this study were met by 38 patients (24 positive-CTS and 14 negative-CTS). Mean finger-to-screen contact duration was longer (144 vs. 107 ms; P<.0001), mean click frequency was lower(3.7 vs. 4.3 Hz; P<.0001) and mean deviation from the center of the circle was greater(14.125 vs. 14.07 pix; P<.0001).In multivariate analysis, only the mean thumb-to-screen contact time was statistically significant (P=.03). The ROC curve for this variable showed high sensitivity (75%) and specificity (86%).

Tapping test parameters significantly correlate with diagnosis of CTS. The collected results allowed us to create the prototype of the next screening tool for CTS. The test is easy to perform (tapping on a screen), simple to interprete (do not need subjective interpretation), universally available (carpaltunnel-test.com) and to have high sensitivity and specificity values.