Wrist Actimetry Biomarker Development of Paretic Upper Limb Use in Post Stroke Patients for Ecological Monitoring.

Background In post-stroke patients it is unclear which wrist actimetry biomarkers to use to estimate the degree of upper limb hemiparesis. The objective of this study was to develop a general and objective framework for monitoring hemiparetic patients in their home environment via different biomarkers based on 7 days of actimetry data. A secondary objective was to use all of these biomarkers to better understand the mechanism for potential non-use of the paretic upper limb. Methods Accelerometers were worn continuously for a period of 7 days on both wrists of 10 post-stroke hemiparetic patients as well as 6 healthy subjects. Various wrist actimetry biomarkers were calculated, including the Jerk ratio 50 (JR50, cumulative probability that the Jerk Ratio is between 0 and 0.5), absolute and relative amounts of functional use of movements of the upper limbs (FuncUse and FuncUseR) and absolute and relative velocities of the upper limbs during functional use (VUL and VULR). For each biomarker, the values of stroke and healthy groups were compared. The correlations between all the biomarkers were studied. Results We studied 10 participants with mild-to-moderate chronic hemiparesis and 6 healthy control participants. FuncUse and VUL of the paretic upper limb of stroke patients were significantly lower than in the non-dominant upper limb of healthy subjects. Similarly, FuncUseR (paretic/non-paretic vs non-dominant/dominant), JR and VULR are significantly lower in stroke patients than in healthy subjects. FuncUseR, VULR and JR50 seem to be complementary biomarkers for monitoring patient strokes. Conclusion The stroke patients do not seem to compensate for the decrease in functional movement on the paretic side by an increase on the non-paretic side. The speed of execution of functional movements on the paretic side could be the limiting factor to a normal use of the paretic upper limb. A thorough clinical study is needed to identify the limiting factors. In conclusion, this study for the first time has shown actimetry is a robust and non-obtrusive lightweight technology for continuously acquiring objective upper limb data of paretic arm use/ non-use over an extended period in a home environment for monitoring stroke patients.