Reliability and Validity of the Bimanual Observation of The Hands (BOTH) for Assessing Bimanual Coordination in Individuals Post-Stroke With Fair-to-Good Motor Ability

ImportanceThe Bimanual Observation of The Hands (BOTH) is a new observation to assess bimanual coordination post-stroke, which has potential to provide clinicians with a simple and functional tool.ObjectiveTo examine the reliability and validity of the BOTH in individuals post-stroke.DesignCross-sectional study.SettingCommunity and in-patient rehabilitation center.ParticipantsIndividuals post-stroke with fair-to-good motor ability of the affected upper extremity.InterventionNot applicable.Outcomes and MeasuresThe BOTH includes eight functional bimanual activities. Additional measures included the Purdue Pegboard Test (PPT; dexterity), ABILHAND (perceived functional use), Box and Block Test (BBT; functional ability), Rating of Everyday Arm-Use in the Community and Home (REACH; daily hand-use), and the Functional Independence Measure (FIM; independence in daily living). Internal-consistency, inter-rater, and test-retest reliability were evaluated using Cronbach's α, intraclass correlation coefficients (ICCs), and Wilcoxon tests. Validity was assessed by Spearman correlations between the BOTH and the PPT, ABILHAND, BBT, REACH and FIM (convergent) and by comparing participants with lower versus higher motor ability (known-groups).ResultsFifty-one adults post-stroke (31.4% women; age 33-88 years) participated. BOTH demonstrated excellent inter-rater reliability (ICC=0.96-0.98), good test-retest reliability (ICC=0.83-0.86), and excellent internal consistency (α>0.90). Strong-moderate correlations supported convergent validity. Known-groups validity was established.Conclusions and RelevanceThe BOTH is a reliable and valid observational tool for assessing bimanual coordination post-stroke. Accurate information regarding bimanual coordination can guide treatment planning to improve functional use of the hands. Further studies are needed to confirm these findings and evaluate responsiveness.