Maximum tolerable daily dose of mirror movement therapy ankle exercises after stroke: an early phase dose screening study

Background: Mirror movement therapy may reduce lower limb motor impairment after stroke. The dose is unknown.

Objective: identify the maximum tolerable dose a day (MTD) of lower limb mirror movement therapy DESIGN: 3 + 3 cohort rule-based, dose escalation/de-escalation study. After undertaking baseline measures participants performed mirror movement therapy for 14 consecutive days. Participants then undertook outcome measures. Cohort One trained for 15 minutes daily. Subsequent cohorts exercised at a dose set according to pre-set rules and the modified Fibonacci sequence. The study stopped when the difference between set doses for consecutive cohorts was 10% or less.

Setting: Participants' homes (intervention) and a movement analysis laboratory (measures).

Participants: Adults discharged from statutory stroke rehabilitation services.

Intervention: Mirror movement therapy ankle exercises.

Outcome measures: Motricity Index (primary) and bilateral time symmetry from movement onset to peak activation of Tibialis Anterior muscles during standardised sit-to-stand (secondary).

Results: Five cohorts of three participants were included (n = 15). Mean (SD) age and time after stroke were 61 (9) years and 35 (42) months respectively. Set daily doses for the five cohorts were: 15, 30, 50, 40 then 35 minutes. The set dose for a subsequent cohort (six) would have been 38 minutes thus the difference from cohort five would have been three minutes i.e., 9% different. Therefore, the study stopped CONCLUSION: The identified MTD of lower limb mirror therapy was 35 minutes daily when frequency was set at seven days a week and duration as two weeks.

Clinical trial registration number: NCT04339803 (ClinicalTrials.gov) CONTRIBUTION OF THE PAPER: This early phase study found that the maximum tolerable dose per day (MTD) of mirror movement therapy ankle exercises was 35 minutes when frequency was set at seven days a week and duration as two weeks. The optimal therapeutic dose will therefore be somewhere in the range of 15 (starting dose) to 35 minutes per day. Further dose articulation studies are required to identify the optimal therapeutic dose before use of findings in clinical practice. This study is the first step in that research process.