Robotic Rehabilitation and Cognitive Functions

It is estimated that up to three quarters of acute and subacute stroke survivors exhibit cognitive impairment. Cognitive impairment can significantly compromise functional recovery, quality of life, and social engagement after stroke. Indeed, some authors showed that the impairment of cognitive functions can negatively influence rehabilitation strategies. Robotic therapy has been proposed as a viable approach for the rehabilitation of the upper limb, as a way to increase the amount and intensity of the therapy, and to standardize the treatment, adding a complex but controlled multisensory stimulation to the patient. In fact, owing to the complex training environments, robotic and technological devices may promote the re-learning capacity, inducing functional or structural plasticity in brain networks that control both motor and cognitive functions. Our hypothesis is that the cognitive engagement of patients during upper limb robotic therapy can impact on some cognitive functions that are compromised after the stroke.

The current pilot study aims to evaluate the effects of an upper limb robotic rehabilitation treatment on cognitive functions in patients with subacute stroke.

Fifty consecutive patients with sub-acute stroke (within 6 months of the event) will be enrolled in two rehabilitation centers.

All patients will perform a robotic treatment of the upper limb (30 sessions, 5 times a week) using a set of robotic devices. The training will include motor-cognitive exercises specifically selected to train spatial attention, vision and working memory, praxis, executive functions, and speed of processing. Furthermore, patients will undergo a comprehensive rehabilitation program including individual conventional physiotherapy (6 times/week), lasting 45 minutes focused on lower limb, sitting and standing training, balance and walking.

Subjects will be evaluated at baseline (T0) and after treatment (T1). To be included in the analysis, patients will have to undergo at least 25 rehabilitation sessions, without interrupting the treatment (due to clinical complications) for more than six consecutive sessions; otherwise, they will be considered as dropouts.

The effects of the rehabilitation intervention on the upper limb function and disability will be assessed with the following clinical scales: Fugl-Meyer Assessment for Upper Extremity (FMA), to evaluate motor function; the Motricity Index (MI), to evaluate muscle strength; the Modified Barthel Index (mBI), to evaluate activities of daily living (ADL) and mobility.

Oxford Cognitive Screen (OCS) will be performed as screening tool to evaluate cognitive functions. Moreover, the following cognitive tests will be used: 1) Digit Span (attention/short-term memory involving strings/series of digits of varying length); 2) Tower of London (planning and problem solving); 3) STROOP test (Stroop Color and Word Test); 4) Symbol Digit Modalities Test (processing speed of visual stimuli); 5) Rey-Osterrieth Complex Figure Test (ROCF) (visuomotor integration).

Inclusion criteria

• first ischemic or hemorrhagic stroke (verified by MRI or CT);
• time latency within 6 months from stroke (subacute patients);
• age between 35-85 years;
• cognitive abilities adequate to understand the experiments and the follow instructions Token test ≥26.5 (correction as for age and school level);
• upper limb impairment (FMA score ≤58);
• ability to give written consent;
• compliance with the study procedures.

Exclusion criteria

• history of recurrent stroke;
• inability to understand the instructions required for the study;
• fixed contraction in the affected limb (ankylosis, Modified Ashworth Scale equal to 4);
• severe deficits in visual acuity.