Recovery and Prediction of Bimanual Hand Use After Stroke

Abstract

Objective: To determine similarities and differences in key predictors of recovery of bimanual hand use and unimanual motor impairment after stroke.

Method: In this prospective longitudinal study, 89 patients with first-ever stroke with arm paresis were assessed at 3 weeks and 3 and 6 months after stroke onset. Bimanual activity performance was assessed with the Adult Assisting Hand Assessment Stroke (Ad-AHA), and unimanual motor impairment was assessed with the Fugl-Meyer Assessment (FMA). Candidate predictors included shoulder abduction and finger extension measured by the corresponding FMA items (FMA-SAFE; range 0-4) and sensory and cognitive impairment. MRI was used to measure weighted corticospinal tract lesion load (wCST-LL) and resting-state interhemispheric functional connectivity (FC).

Results: Initial Ad-AHA performance was poor but improved over time in all (mild-severe) impairment subgroups. Ad-AHA correlated with FMA at each time point (r > 0.88, p < 0.001), and recovery trajectories were similar. In patients with moderate to severe initial FMA, FMA-SAFE score was the strongest predictor of Ad-AHA outcome (R ² = 0.81) and degree of recovery (R ² = 0.64). Two-point discrimination explained additional variance in Ad-AHA outcome (R ² = 0.05). Repeated analyses without FMA-SAFE score identified wCST-LL and cognitive impairment as additional predictors. A wCST-LL >5.5 cm³ strongly predicted low to minimal FMA/Ad-AHA recovery (≤10 and 20 points respectively, specificity = 0.91). FC explained some additional variance to FMA-SAFE score only in unimanual recovery.

Conclusion: Although recovery of bimanual activity depends on the extent of corticospinal tract injury and initial sensory and cognitive impairments, FMA-SAFE score captures most of the variance explained by these mechanisms. FMA-SAFE score, a straightforward clinical measure, strongly predicts bimanual recovery.

Clinicaltrialsgov identifier: NCT02878304.

Classification of evidence: This study provides Class I evidence that the FMA-SAFE score predicts bimanual recovery after stroke.

Figure 1. Flowchart of the Recruitment Process

Recruitment was initiated in March 2013 and ended in September 2019.

Figure 2. Individual Case Profiles and Group Mean (A–C) and Bimanual Activity Performance (D), Arm (E), and Hand (F) Motor Impairment Estimated Marginal Means Across Impairment Severity Subgroups

(A–C) Individual case profiles (raw scores) of Adult Assisting Hand Assessment Stroke (Ad-AHA) (A), Fugl-Meyer Assessment for the upper extremity (FMA-UE) (B), and Fugl-Meyer Assessment hand (FMA-Hand) subscale (C). Colors illustrate initial motor impairment sub-groups according to the FMA-UE score (mild >47points [green], moderate 20–47 points [blue], and severe ≤19 points [red]). Dark bars represent whole group absolute mean. (D–F) Effects of time by group analyzed using linear mixed effects model. Each marker represents the estimated marginal means per subgroup and time point. Vertical bars are 95% confidence intervals.

Figure 3. Scatterplots Illustrating Linear Association Between Dependent Variables (Ad-AHA and FMA Score) and FMA-SAFE Score

A positive linear association was found between bimanual activity performance (Adult Assisting Hand Assessment Stroke [Ad-AHA]) and arm and hand motor impairment (Fugl-Meyer Assessment for the upper extremity [FMA-UE]) (A). A similar pattern was found regarding recovery, between both Ad-AHA and FMA-UE scores (B) and Ad-AHA and the Fugl-Meyer Assessment of hand (FMA-Hand) (C) scores. However, note that a full recovery in FMA-Hand score (recovery ratio 1) did not equal a correspondingly full recovery in Ad-AHA score (C). Strong associations were also found between bimanual and unimanual outcome and recovery and for Fugl-Meyer Assessment of shoulder abduction and finger extension (FMA-SAFE) score, most prominent in the severe impairment group (D–F). Ad-AHA outcome vs FMA-SAFE score: moderate: R = 0.38, p = 0.109 and severe: R = 0.82, p < 0.0001 (D); Ad-AHA recovery vs FMA-SAFE score: moderate: R = 0.50, p = 0.028 and severe: R = 0.76, p < 0.0001 (E); FMA-UE outcome vs FMA-SAFE score: moderate: R = 0.42, p = 0.077 and severe: R = 0.89, p < 0.0001 (F). FMA-UE recovery vs FMA-SAFE score: moderate: R = 0.36, p = 0.137 and severe: R = 0.86, p < 0.0001 (G).

Figure 4. Predictive Threshold of CST Injury (wCST-LL) of 5.5 cm³ Was Identified by ROC Curve Analysis Separating Patients Who Showed a Minimum Clinically Meaningful Change in FMA-UE Score of 10 Points From Those Who did Not

Receiver operating characteristic (ROC) curve–derived predictive threshold of 5.5 cm³ corticospinal tract (CST) lesion load had a sensitivity of 0.73 and specificity of 0.91 (1 − 0.09) (A). Unimanual arm and hand actual change (Fugl-Meyer Assessment for the upper extremity [FMA-UE], 6-month status minus status at 3 weeks) against weighted CST lesion load (wCST-LL) (B). Red dotted line (B and C) demarks 5.5 cm³. Adult Assisting Hand Assessment Stroke (Ad-AHA) score against wCST-LL illustrating a pattern similar to that of FMA-UE score, with a limited amount of actual change in patients with a wCST-LL >5.5 cm³ and high interindividual variance in patients with a wCST-LL <5.5 cm³ (C).