Feasibility of using acceleration-derived jerk to quantify bimanual arm use.

BACKGROUND: Accelerometers have become common for evaluating the efficacy of rehabilitation for patients with neurologic disorders. For example, metrics like use ratio (UR) and magnitude ratio (MR) have been shown to differentiate movement patterns of children with cerebral palsy (CP) compared to typically-developing (TD) peers. However, these metrics are calculated from "activity counts" - a measure based on proprietary algorithms that approximate movement duration and intensity from raw accelerometer data. Algorithms used to calculate activity counts vary between devices, limiting comparisons of clinical and research results. The goal of this research was to develop complementary metrics based on raw accelerometer data to analyze arm movement after neurologic injury. METHOD: We calculated jerk, the derivative of acceleration, to evaluate arm movement from accelerometer data. To complement current measures, we calculated jerk ratio (JR) as the relative jerk magnitude of the dominant (non-paretic) and non-dominant (paretic) arms. We evaluated the JR distribution between arms and calculated the 50th percentile of the JR distribution (JR50). To evaluate these metrics, we analyzed bimanual accelerometry data for five children with hemiplegic CP who underwent Constraint-Induced Movement Therapy (CIMT) and five typically developing (TD) children. We compared JR between the CP and TD cohorts, and to activity count metrics. RESULTS: The JR50 differentiated between the CP and TD cohorts (CP = 0.578 ± 0.041 before CIMT, TD = 0.506 ± 0.026), demonstrating increased reliance on the dominant arm for the CP cohort. Jerk metrics also quantified changes in arm use during and after therapy (e.g., JR50 = 0.378 ± 0.125 during CIMT, 0.591 ± 0.057 after CIMT). The JR was strongly correlated with UR and MR (r = - 0.92, 0.89) for the CP cohort. For the TD cohort, JR50 was repeatable across three data collection periods with an average similarity of 0.945 ± 0.015. CONCLUSIONS: Acceleration-derived jerk captured differences in motion between TD and CP cohorts and correlated with activity count metrics. The code for calculating and plotting JR is open-source and available for others to use and build upon. By identifying device-independent metrics that can quantify arm movement in daily life, we hope to facilitate collaboration for rehabilitation research using wearable technologies.

Accelerometer Measurements Indicate That Arm Movements of Children With Cerebral Palsy Do Not Increase After Constraint-Induced Movement Therapy (CIMT).

IMPORTANCE: Constraint-induced movement therapy (CIMT) is a common treatment for children with unilateral cerebral palsy (CP). Although clinic-based assessments have demonstrated improvements in arm function after CIMT, whether these changes are translated and sustained outside of a clinic setting remains unclear. OBJECTIVE: Accelerometers were used to quantify arm movement for children with CP 1 wk before, during, and 4 wk or more after CIMT; measurements were compared with those from typically developing (TD) peers. DESIGN: Observational. SETTING: Tertiary hospital and community. PARTICIPANTS: Seven children with CP (5 boys, 2 girls; average [AVE] age ± standard deviation [SD] = 7.4 ± 1.2 yr) and 7 TD peers (2 boys, 5 girls; AVE age ± SD = 7.0 ± 2.3 yr). INTERVENTION: 30-hr CIMT protocol. OUTCOMES AND MEASURES: Use ratio, magnitude ratio, and bilateral magnitude were calculated from the accelerometer data. Clinical measures were administered before and after CIMT, and parent surveys assessed parent and child perceptions of wearing accelerometers. RESULTS: During CIMT, the frequency and magnitude of paretic arm use among children with CP increased in the clinic and in daily life. After CIMT, although clinical scores showed sustained improvement, the children's accelerometry data reverted to baseline values. Children and parents in both cohorts had positive perceptions of accelerometer use. CONCLUSIONS AND RELEVANCE: The lack of sustained improvement in accelerometry metrics after CIMT suggests that therapy gains did not translate to increased movement outside the clinic. Additional therapy may be needed to help transfer gains outside the clinic. WHAT THIS ARTICLE ADDS: Accelerometer measurements were effective at monitoring arm movement outside of the clinic during CIMT and suggested that additional interventions may be needed after CIMT to sustain benefits.

Physical and Occupational Therapy for a Teenager with Acute Flaccid Myelitis: A Case Report.

AIMS: The purpose of this case report is to describe the inpatient rehabilitation program of a 13-year-old boy with acute flaccid myelitis (AFM), specific to physical and occupational therapy examination, treatment, and outcomes. CASE DESCRIPTION: AFM is a rare, acute neurologic illness in children and young adults who present with weakness and/or paralysis of unknown etiology. The teenager was admitted to the program, dependent for all mobility and self-care. Interventions focused on range of motion, transfer training, self-care, power wheelchair mobility, and environmental adaptations. OUTCOMES: Weekly re-evaluations and the WeeFIM were used at admission and discharge to measure the teenager's progress. At discharge, the teenager had made small gains in his passive and active range of motion. He was independent in directing his care and able to drive his power wheelchair with supervision. DISCUSSION: Due to the scarcity of published data describing AFM, this report describes an individual's response to a rehabilitation program and will hopefully add to future research in order to provide patients and families with expectations for their recovery and ultimate level of function.