Bimanual Assessment Measure (BAM): Development of a Measure of Bimanual Function for Use After Stroke

SIGNIFICANCE: Impaired hand function is the number-one complaint after stroke. While rehab interventions have traditionally focused on affected hand function, attention has more recently turned toward treatment of bimanual coordination. Despite the ecological relevance of this treatment, there is currently no known comprehensive outcome measure of bimanual function. The Bimanual Assessment Measure (BAM) will be the first comprehensive measure of bimanual functioning. That is, BAM not only takes into account an individual’s ability to bimanually complete activities of daily living and instrumental activities daily living but also considers functional hand roles (i.e., as a stabilizer or manipulator).

APPROACH: Our purpose was to develop a brief, low cost, mobile app-based measure of bimanual performance that is easy to administer and incorporates common bimanual functional tasks. While the effects of stroke are typically thought of as unimanual deficits, coupling that is typically present between the hands during bimanual coordination is also impaired. Although bimanual interventions have demonstrated effectiveness at the level of coordination impairments, the clinical meaningfulness of these improvements is unknown. This stems largely from the current lack of a comprehensive functional performance measure of bimanual control.

METHOD: Content validity establishment has begun with three individuals with stroke and a focus group of occupational therapists (OTs). A university research setting was used. Three individuals with chronic stroke (>6 mo) and licensed and practicing OTs from a local hospital were recruited as a convenience sample. The BAM is aimed at assessing bimanual function in people with stroke, with some level of volitional movement of both upper extremities. Scoring consists of three primary criteria: (1) Was each hand spontaneously used in its natural role as a manipulator or stabilizer based on hand dominance?; (2) Was task completed within an appropriate time frame?; and (3) Did they complete the task bimanually with appropriate hand roles (i.e., manipulator or stabilizer)? All included items consist of common, everyday tasks that typically require bimanual coordination for completion. Standardization is applied to the order of task completion, instructions, as well as physical setup. Input from individuals with stroke and OTs were used to guide item selection and refinement as well as overall layout and script of the BAM.

RESULTS: BAM items related to independent community functioning supported the initial item selection, including the 11 current functional tasks that include specific components of bimanual coordination. A web-based version has been developed and includes considerations to dominant, non-dominant hands, and functional hand role (i.e., stabilizer or manipulator).

CONCLUSION: As a first step toward development, BAM demonstrates good content validity. Further validity and reliability testing, as well as Rasch analysis, are needed in order to complete BAM development with the ultimate goal of a mobile app-based version for clinical use.