Effect of Exteroceptive Stimulation Combined With Conventional Physiotherapy on Lip Angle Deviation and Facial Function in Patients With Post-Stroke Facial Palsy: A Double-Blind Randomized Controlled Trial

Post-stroke facial palsy is a frequent neurological complication resulting from upper motor neuron lesions affecting facial nerve pathways. It commonly presents with facial asymmetry, impaired voluntary muscle control, and altered emotional expression. These deficits can interfere with communication, oral competence, and social interaction, ultimately impacting functional independence and quality of life. Despite its clinical importance, rehabilitation strategies targeting facial motor recovery remain relatively underdeveloped compared to limb rehabilitation.

Conventional physiotherapy approaches for facial palsy typically focus on facial muscle exercises, facilitation techniques, and functional retraining aimed at improving motor control and symmetry. While these approaches are widely used in clinical practice, their outcomes are often variable, and recovery may be incomplete. In recent years, there has been increasing interest in integrating sensory-based interventions into neurorehabilitation, based on the premise that sensory input plays a critical role in motor relearning and cortical reorganization.

Exteroceptive stimulation is a sensory-based intervention designed to enhance afferent input through external stimuli applied to the skin and underlying tissues. By increasing sensory feedback, it may facilitate neuromuscular activation, improve motor coordination, and support adaptive neuroplastic changes. Although such approaches have shown promise in broader neurorehabilitation contexts, their role in the management of post-stroke facial palsy has not been sufficiently investigated through controlled clinical trials.

This study was designed as a double-blind randomized controlled trial to examine the additional benefit of exteroceptive stimulation when combined with conventional physiotherapy. Participants diagnosed with post-stroke facial palsy were recruited from tertiary care settings and randomly assigned to one of two intervention groups using a computer-generated randomization process. Measures were taken to ensure blinding of participants and outcome assessors to minimize bias.

The intervention was delivered over a defined treatment period, with both groups receiving standardized conventional physiotherapy to ensure consistency of baseline care. The experimental group received an additional structured program of exteroceptive stimulation targeting affected facial regions. The protocol was designed to be feasible within routine clinical practice and reproducible in similar healthcare settings.