Ecological Assessment of Upper-Extremity Physical Rehabilitation Outcomes

Introduction Widely accepted models of disability suggest that how much a neurologically-impaired arm is actually used in everyday life frequently deviates from its motor capacity, as measured by laboratory tests. Yet, until recently, instruments in physical rehabilitation did not directly assess real-word use of the impaired arm after stroke and other types of brain injury this paper describes an objective approach for remotely monitoring impaired-arm use in daily life.

Methods Patients wore an accelerometer just above each wrist for two days outside of the laboratory. The accelerometers were sensitive to movement in two axes, and sampled acceleration at 10 Hz. The 10 Hz samples were integrated over a 2-s recording epoch; the integral gave a rough reflection of the amount of arm movement during the epoch. Real-world impaired-arm use was indexed by the number of epochs containing movement (i.e., epoch value > 2) in the impaired-arm recordings divided by the corresponding number for the unimpaired arm. reliability and validity of this ratio for measuring upper-extremity rehabilitation outcomes were assessed in a single-site study (Study 1; N = 20) and a multi-site study (Study 2; N = 169) of stroke survivors with mild to moderate impaired-arm motor deficit.

Results In both studies, the correlation between the ration values from two observation periods separated by 2 weeks of no treatment was >.8. For data from the first observation period, the correlation between the ratio values and a convergent, structured interview assessing real-world impaired-arm use was .74 in Study 1 and .52 in Study 2.

Discussion The ratio of impaired- to unimpaired-arm movement reliably and validly measures real-world upper-extremity rehabilitation outcome after stroke.

Conclusion Advances in ecological assessment of motor behavior after neurological injury, such as described here, will permit researchers to distinguish rehabilitation that actually makes a difference in daily life from rehabilitation that only influences motor capacity.