Effects and Mechanisms of Sensory Afferent Electrostimulation on Upper Limb Function in Patients With Hemiparesis

Children with hemiparesis present with sensory and motor deficits, which negatively affect quality of life and decrease participation in everyday life. To date, no treatment is yet effective to decrease these impairments. A recent systematic review confirms that unimanual and bimanual trainings effectively improve upper limb function in children with hemiparesis. However, it is still challenging to find the best individual training method for children with hemiparesis, as there is much variability in treatment response.

In the present study, the effects and mechanisms of non-invasive electrostimulation of the hand, called Sensory Afferent Electrostimulation (SAES) will be investigated. SAES triggers action potentials in afferent nerve fibres leading to increased sensory afferent input in the sensorimotor regions of the brain. Through this, SAES can enhance excitability of the motor cortex and of upper limb performance. While proven effective in adults after stroke, SAES is safe with promising positive results in a very small study in children with hemiparesis. However, the investigation of efficacy of SAES on sensory and motor functions was so far neglected. Modern stimulation and imaging methods revealed that, whole-hand SAES induced increased strength of corticospinal projections and intracortical change (measured with transcranial magnetic stimulation), which may indicate long-term potentiation mechanisms. Furthermore, in a functional MRI study, SAES induced increased motor cortex activity. Hence, resting state fMRI will allow to understand the efficacy of SAES on the topographically connectivity of the motor and sensorimotor network at rest.

The experimental intervention consists of SAES with a glove or adhesive electrodes (e.g. Cefar Reha X2) at 20Hz, 300µs, intensity between 2-10mA, during 30 minutes per day, 5x/week, for 5 weeks, combined with conventional occupation therapy. The subsequent therapy sessions will take place at home, with in-between telephone checks.

The control intervention (treatment as usual, TAU) consists of the prescribed conventional occupational therapy and/or physiotherapy. The evaluation of the UL sensory and motor function will be conducted at the University Children's Hospital in Bern by blind assessors, expert in the clinical measures, and will take place before and after each intervention period and at 12-weeks follow-up.

Inclusion criteria

• Diagnosis of unilateral cerebral palsy/hemiparesis, following unilateral brain lesion, e.g. perinatal/childhood stroke (acquired prior to the age of 16 years)
• consistent and stable limitation of hand functions
• chronic state (time since lesion >2 years)
• aged 6-18 years
• parental informed consent if <14 years, informed consent of the patient if >14 years

Exclusion criteria

• psychiatric disease that prevents the participant form informed participation and compliance in an adequate manner/setting
• Bilateral brain lesion
• Recent Botulinum toxin-injections injections (UL, < 6 months)
• Hand surgery on paretic hand < 2 years
• Trauma to UL in the last year
• Medical conditions that prevent training of the UL
• Participation in other afferent stimulation studies
• Electrical stimulation therapy in the last 6 months
• Intensive training of the UL (therapy more than 1x/week, < 6 months)

If MRI and TMS is performed, additionally:

• MRI and TMS contradictions, such as

• implanted Metal devices (e.g. braces, implant)
• implanted shunt system
• in girls and women: pregnancy
• claustrophobia
• Active epilepsy