APP-Coo-Test: un’applicazione per dispositivi touch screen in grado di valutare quantitativamente la compromissione del movimento degli arti superiori e dell’equilibrio dei pazienti con atassia cerebellare

Background The use of objective measurements is essential to assess disease progression and to evaluate the effectiveness of rehabilitation protocols and clinical treatments. Aim The purpose of this study was to develope a touch-screen application, that we named 15-White Dots APP-Coo-Test (15-WDACT), able to carry out quantitative and objective measurements of the rapid and coordinated upper limb movements, typically impaired in patients with cerebellar ataxias (CA). Methods A total of 87 CA patients and 170 healthy subjects participated in this study. The subject was asked to touch with their index finger a white dot, appearing consecutively and randomly on the screen at different positions, for a total of 15 dots per session. The score is the execution time of a single session. Results 15-WDACT measurements have highly correlated with the scores obtained with the Scale for the Assessment and Rating of Ataxia (SARA), with the Composite Cerebellar Functional Severity (CCFS) and with the measurements obtained using two validated evaluating systems i.e. the Nine Hole Pegboard test (9HPT) and the Click test. We also observed high internal consistency and an excellent intra-rater and test-retest reliability. We found a small Standard Error of Measurement (SEM) and an excellent Minimal Detectable Change (MDC), indicating that even small variations in the 15-WDACT measurements are to be associated with real changes in performance. Conclusions We have concluded that 15-WDACT is an easy, fast and reliable tool to assess the severity of the upper limb ataxia in patients with CA. Uncertain gait and unstable static balance are some characteristics of patients with cerebellar ataxias (CA). The aim of this study was to develop an application (APP) able to assess static and dynamic balance in CA patients. The APP that works by a wearable device (mobile-phone) placed at the breastbone level and immobilized by an elastic band, assesses the oscillations of the trunk by an accelerometer technology. The APP provides different scores based on patient position: “Feet Together”; “On a Broad Base”; “Sitting”. We investigated 80 healthy subjects and 32 CA patients. We observed a strong linear correlation between the results obtained with the new application and the measurements obtained using two validated evaluating systems i.e. Prokin-212-N footboard (static balance) and G-Walk inertial systems (gait analysis). A strong correlation was also observed between the APP measurements and the severity of ataxic symptomology, as assessed by the “Scale for the Assessment and Rating of Ataxia” (SARA). The internal consistency, the intra-rater reliability and the test-retest reliability of the APP measurements, estimated by intraclass correlation coefficient (ICC2.1), was excellent. We can state that the APP is an easy and valid evaluating system able to quantitatively assess the oscillations of the trunk in a static position and during the gait. As these symptoms tend to get worse with time in CA patients, our results suggest that the APP could be an alternative evaluate system able to assess the disease progression and the effectiveness of rehabilitation protocols and clinical treatments. Upper limb movement impairment is one of the characteristics of Friedreich’s ataxia (FRDA). The use of standardized tools is most important to test the effectiveness of new drugs or rehabilitative protocols. The aim of our study was to develop an application for touch screen device, able to assess the upper limb movement impairment in patients with FRDA, even in those with severe ataxia. The APP, that we named “Twelve Red Squares App-Coo-Test” (12-RSACT), assesses the upper limb ataxia by measuring the test execution time. We investigated 122 controls and 35 FRDA patients. We observed a strong linear correlation between the measurements obtained with the 12-RSACT and those obtained with the Nine Hole Peg Test (R = 0.74). The correlation between the 12-RSACT execution times and the scores obtained with the Scale for the Assessment and Rating of Ataxia, was strong too (R = 0.81). The 12-RSACT was characterized by excellent intra-rater reliability (intra-class coefficients ICC2.1 ranging from 0.970 to 0.996), high accuracy of the obtained data (coefficients of variation on average of 4.3%)) and excellent test-retest reliability (ICC2.1 = 0.984). Internal consistency, as indicated by Cronbach’s alpha of 0.994, was excellent too. Therefore, the 12-RSACT is a valid and easy-to-use application that can reliably assess the upper limb movement impairment in FRDA patients.