Relationship between intensity and recovery in post-stroke rehabilitation: a retrospective analysis.

Work in animal models suggests high-intensity rehabilitation-based training that starts soon after stroke is the most effective approach to promote recovery.1 In humans, the interaction between treatment onset and intensity remains unclear.2 It has been suggested that reducing daily treatment duration below 3 hours at the acute and subacute stages leads to a poorer prognosis,3 while there may also be an upper bound beyond which high-intensity motor rehabilitation at the acute stage might lead to unwanted side effects.4 Designing optimal rehabilitation treatment programmes for stroke patients will not be possible until we understand ‘how much’, ‘when’ and ‘what’ treatment should be delivered.2 In this retrospective analysis, we assessed patients’ responsiveness to high-intensity and low-intensity rehabilitation protocols across different stages of chronicity post-stroke to address the ‘how much’ and ‘when’ questions. The Queen Square Upper Limb Neurorehabilitation (QSUL)5 and the Rehabilitation Gaming System (RGS)6 datasets comprise a cohort of 455 individuals with upper-limb hemiparesis treated between 2008 and 2018 at different stages of chronicity post-stroke (subacute 4 years).7 The QSUL programme delivered a 3-week high-intensity rehabilitation programme (high-intensity conventional treatment (H-CT), 6 hours daily, 5 days per week, 90 hours in total) based on a combination of conventional therapies (n=224). The RGS cohort (n=231) followed a 3–12 weeks low-intensity treatment programme (20–30 min/session, 3–5 days a week, 7.5–30 hours in total) consisting of either conventional treatment (low-intensity conventional treatment (L-CT), n=69, 30%) or computer-based embodied goal-oriented rehabilitation in virtual reality that was automatically adjusted to the patient’s performance (low-intensity RGS-based neurorehabilitation (L-RGS), n=162, 70%). Participants underwent assessment with the upper extremity section of the Fugl-Meyer (UE-FM) scale at baseline, end of treatment (weeks 3–6) and …