TY - JOUR
T1 - Smartphone Apps Provide a Simple, Accurate Bedside Screening Tool for Orthostatic Tremor
AU - Bhatti, Danish
AU - Thompson, Rebecca
AU - Hellman, Amy
AU - Penke, Cynthia
AU - Bertoni, John M.
AU - Torres-Russotto, Diego
N1 - Publisher Copyright:
© 2017 International Parkinson and Movement Disorder Society
PY - 2017/11/1
Y1 - 2017/11/1
N2 - Background: Orthostatic Tremor (OT) is characterized by the presence of a sensation of instability while standing, associated with high frequency (13–18 Hz) lower extremity tremor. Diagnosis is confirmed with surface electromyography (EMG). An accurate screening tool that could be used in the routine clinical setting, without any specialized equipment, would be useful in earlier detection of OT and judicial use of additional testing. Objective: The objective of this study was to evaluate OT diagnostic test characteristics at bedside using iPhone's built-in accelerometer and available applications for tremor recordings. Methods: We obtained recordings using iPhones (Model 5, 5s, and 6) and free Applications (“LiftPulse” by LiftLabs [App1] and “iSeismometer” by ObjectGraph LLC [App2]) at default settings. Results: 24 EMG-confirmed OT subjects (mostly females, 22/24) and 15 age-matched controls (mostly males, 11/15) were evaluated. App1 detected OT range tremor in 22/24 patients and none of the controls. (Sensitivity = 92%, Specificity = 100%, NPV = 88%). App2 detected OT range tremor in 21/24 patients and in 1/13 controls (Sensitivity = 88%, Specificity = 92%, NPV = 80%). When combined, 24/24 patients and 1/13 controls had OT range tremor (Sensitivity = 100%, Specificity = 92%, NPV = 100%). Conclusions: Smartphone apps that use the built-in accelerometer provide a simple, accurate and inexpensive bedside screening diagnostic tool for patients with OT.
AB - Background: Orthostatic Tremor (OT) is characterized by the presence of a sensation of instability while standing, associated with high frequency (13–18 Hz) lower extremity tremor. Diagnosis is confirmed with surface electromyography (EMG). An accurate screening tool that could be used in the routine clinical setting, without any specialized equipment, would be useful in earlier detection of OT and judicial use of additional testing. Objective: The objective of this study was to evaluate OT diagnostic test characteristics at bedside using iPhone's built-in accelerometer and available applications for tremor recordings. Methods: We obtained recordings using iPhones (Model 5, 5s, and 6) and free Applications (“LiftPulse” by LiftLabs [App1] and “iSeismometer” by ObjectGraph LLC [App2]) at default settings. Results: 24 EMG-confirmed OT subjects (mostly females, 22/24) and 15 age-matched controls (mostly males, 11/15) were evaluated. App1 detected OT range tremor in 22/24 patients and none of the controls. (Sensitivity = 92%, Specificity = 100%, NPV = 88%). App2 detected OT range tremor in 21/24 patients and in 1/13 controls (Sensitivity = 88%, Specificity = 92%, NPV = 80%). When combined, 24/24 patients and 1/13 controls had OT range tremor (Sensitivity = 100%, Specificity = 92%, NPV = 100%). Conclusions: Smartphone apps that use the built-in accelerometer provide a simple, accurate and inexpensive bedside screening diagnostic tool for patients with OT.
KW - accelerometer
KW - application
KW - orthostatic tremor
KW - smartphone
KW - tremor frequency
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U2 - 10.1002/mdc3.12547
DO - 10.1002/mdc3.12547
M3 - Article
C2 - 30363432
AN - SCOPUS:85063621887
SN - 2330-1619
VL - 4
SP - 852
EP - 857
JO - Movement Disorders Clinical Practice
JF - Movement Disorders Clinical Practice
IS - 6
ER -