Deep brain stimulation of the motor thalamus to improve orofacial motor and speech production deficits after stroke - more than 5 million people in the US alone experienced difficulty speaking…

The National Institute of Neurological Disorders and Stroke awarded the University of Pittsburgh a cooperative agreement totaling $312,858 on September 1, 2026, to test the safety, feasibility, and early efficacy of deep brain stimulation of the motor thalamus to improve speech intelligibility in people with chronic post-stroke dysarthria. The award funds research under the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative (CFDA 93.372).

The project will investigate whether electrical stimulation to the motor thalamus can increase excitability of cortical motor neurons and facilitate residual connections to restore speech production in stroke survivors with orofacial motor deficits. The research hypothesizes that stimulation delivered at speech onset will produce immediate assistive effects and superior long-term recovery when combined with speech therapy. Preliminary data from non-human primate models and a patient case with severe speech deficits from traumatic cortical-spinal tract injury demonstrate the proposed mechanism of action.

Work is performed in Pittsburgh, Pennsylvania, with a period of performance from September 1, 2026 through February 28, 2027.

Deep brain stimulation of the motor thalamus to improve orofacial motor and speech production deficits after stroke - more than 5 million people in the US alone experienced difficulty speaking (dysarthria) as a conse- quence of stroke. Currently, dysarthria is palliated with behavioral speech therapy, but the efficacy of these methods relies on patient retention, leaving subjects with moderate and severe deficits unable to effectively communicate, resulting in greater isolation, depression, and accelerated deterioration of health. Project goal: here we aim at testing the safety, feasibility and early efficacy of a system delivering electrical stimulation to the motor thalamus to improve speech intelligibility in people with chronic post-stroke dysarthria. Hypothesis: in most cases, damage to the cortico-spinal and cortico-bulbar tracts controlling speech motor functions are incomplete, but the spared excitatory descending inputs are insufficient to activate the motoneurons, leading to functional motor paresis and speech production deficits. Facilitation of the activation of the residual connections could reestablish the missing excitation restoring speech functions. Here we hypothe- size that deep brain stimulation (DBS) of the motor thalamus could increase the excitability of cortical motor neurons, thus facilitating the residual connections and, as a consequence, enhancing speech production. These effects will be immediate (assistive effects) and will lead to superior long-term recovery when combined with speech therapy. Additionally, delivery of bursts of stimulation at speech onset would maximize DBS efficacy. Preliminary data: we demonstrated these mechanisms of action of motor thalamus DBS in non-human PRI- mates. We then tested assistive effects of DBS over orofacial muscles and speech production in a patient with severe speech deficits in consequence of a traumatic injury in the cortical spinal tract (supra-spinal segment) who was implanted with a motor thalamus DBS system. We showed that DBS of the motor thalamus substantially improved orofacial muscle activation, range of motion during facial expression and speech intelligibility. Moreo- VER, DBS did not induce pain or discomfort at intensities that were necessary to obtain functional improvements. Approach: in the UG3 phase of our proposal (year 1) we will obtain FDA approval for an IDE study exploring preliminary safety and efficacy of long-term DBS to improve speech intelligibility in patients with chronic post- stroke dysarthria. In the UH3 (years 2-5) we will execute an early feasibility study testing the efficacy of motor thalamus DBS in combination with 6 weeks of speech therapy to increase orofacial muscle strength, ameliorate speech production, and improve speech intelligibility in up to 10 subjects with chronic post-stroke dysarthria. In the study, patients will be followed up for 1-year to monitor long-term safety and early efficacy and to compare continuous stimulation and targeted bursts at speech onset to inform the optimal parameters for follow up trials. Perspective: our clinical trial will be the first to assess the safety, feasibility and early efficacy of neurostimula- tion therapies targeting the motor thalamus in patients with moderate-to-severe dysarthria, potentially leading to a paradigm-shift in speech rehabilitation. 1