Enhancing Sensory Discrimination Training using Brain Modulation

Sammanfattning: Damage to the nervous system may cause sensorimotor impairment, often resulting in chronic neuropathic pain. Phantom limb pain affects multiple amputees and the treatment options are limited. A promising treatment option to reduce chronic pain is by training sensory discrimination. At the Center for Bionics and Pain Research, a sensory training device has been developed. Transcranial direct current stimulation (tDCS) is a technique to stimulate different regions of the cerebral cortex. In studies, anodal tDCS of the sensorimotor cortex has shown to improve tactile acuity. Until now, the effect of the sensory discrimination training, performed with the sensory training device, in combination with tDCS has not been tested. The purpose of this master’s thesis was to determine the effect of tDCS applied on the sensorimotor cortex on the outcomes of sensory discrimination training. The purpose was also to compare the effect of two different methods of stimulation, namely conventional and High Definition tDCS. 16 able-bodied participants underwent three single sessions with 40 minutes of sensory discrimination training: one session combined with conventional tDCS, one session combined with High Definition tDCS and one session without tDCS. The tactile acuity was determined by the two-point discrimination test and the Semmes-Weinstein monofilament test, prior to and one hour after each session. This study showed that 40 minutes of sensory discrimination training was sufficient to improve the two-point discrimination in the sensory trained areas, compared to the sensory untrained areas (p=0.02). However, the improvement in two-point discrimination was not statistically significant between the interventions, i.e. the improvement in two-point discrimination for the sessions with brain modulation was not statistically significant compared to the session without brain modulation. The monofilament assessments showed an improvement in monofilament score for the sensory untrained skin patches (p=0.053). This study concluded that single sessions of training was enough to improve two-point discrimination but not monofilament score at the site of stimulation. This study lays a foundation for what parameters to include in future studies.