Transcranial Direct Current Stimulation (tDCS) and Cognitive Empowerment for the Functional Recovery of Diseases with Chronic Impairment and Genetic Etiopathogenesis

Transcranial direct current stimulation (tDCS) is a non-invasive, painless brain stimulation treatment that uses direct electrical currents of low intensity to stimulate specific parts of the brain. tDCS could both facilitate (anodic stimulation) and inhibit (catodic stimulation) specific areas of the brain (Ardolino, Bossi, Barbieri, & Priori, 2005), as many neurological and psychiatric disorders are linked to a hypofunction or hyperfunction of specific areas of the nervous system. Such phenomenon is based on two processes: rearrangement of functional neural circuits, and their reconstruction (Kaas, & Garraghty, 1989; Kandel, Schwartz, & Jessell, 2000). In light of the studies mentioned above, it is assumed that tDCS can represent a useful tool to facilitate the process of neuroplasticity in subjects affected by chronic neurological diseases and genetic etiopathogenesis, such as Rett Syndrome (RTT). The aim of the present study is to examine the neurophysiological and cognitive effects of cognitive empowerment combined with tDCS in young girls and women with RTT, with chronic language impairments. Despite results in cognitive rehabilitation showing a positive trend, the efficacy of specific intervention on articulated speech is less consolidated. Lack of current research on successful outcomes in language production prompted the current study, which focuses more on intervention of articulated speech and cognitive functions. In this chapter, we propose an integrated intervention: tDCS and cognitive empowerment applied to language in order to boost speech production (new functional sounds and new words). Given that maximal gains are usually achieved when tDCS is coupled with behavioural training, we applied tDCS stimulation on Broca’s area together with linguistic training. Fourteen young girls and women with RTT were randomly allocated into two subgroups: AtDCS (n = 7) or placebo tDCS (n = 7). tDCS was applied over Broca’s area for a 20-minute session for ten consecutive days. During tDCS stimulation, speech rehabilitation was divided into two sessions: production of vowels and word associations, and discrimination between corresponding words and images. Neurophysiological and cognitive parameters were measured at baseline, post-training and one month after intervention. Results show a general enhancement in language, motor coordination and neurophysiological parameters in the AtDCS group compared to the placebo group. The present study provides evidence that tDCS combined with cognitive empowerment can improve language abilities and motor coordination and foster brain plasticity in young girls and women with RTT. Hence, this study supports the role of tDCS stimulation as a new methodology in the rehabilitation of diseases with chronic impairment and genetic etiopathogenesis.