Exteroceptive Stimulation for Facial Palsy After Stroke

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

Stroke is a leading cause of long-term disability worldwide and frequently results in central facial palsy, which manifests as facial asymmetry, impaired muscle control, and reduced functional ability. These impairments can affect speech, emotional expression, and overall quality of life. Conventional physiotherapy is commonly used to manage post-stroke facial palsy; however, the additional benefit of sensory-based rehabilitation approaches remains insufficiently explored, particularly in clinical settings with limited resources.

This study was conducted to evaluate whether the addition of exteroceptive stimulation to conventional physiotherapy leads to greater improvement in facial symmetry and functional outcomes compared to conventional physiotherapy alone. Exteroceptive stimulation aims to enhance sensory input and facilitate neuromuscular activation, potentially improving motor recovery in affected facial muscles.

In this double-blind randomized controlled trial, a total of 36 participants diagnosed with post-stroke facial palsy were recruited and randomly allocated into two groups. The experimental group received exteroceptive stimulation in addition to conventional physiotherapy, while the control group received conventional physiotherapy alone. Both interventions were administered over a period of four weeks.

Outcome measures were assessed at baseline and at the end of the intervention period. The primary outcome was lip angle deviation, used as an indicator of facial symmetry. Secondary outcomes included facial function and disability assessed using standardized tools such as the Facial Disability Index and the Synkinesis Assessment Questionnaire.

The findings of this study aim to provide evidence on the effectiveness of integrating sensory-based techniques into routine rehabilitation programs for post-stroke facial palsy. The results may support the development of more comprehensive and effective rehabilitation strategies to improve patient outcomes.

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.

Outcome assessments were conducted at predefined time points using validated clinical instruments to capture changes in facial symmetry, functional ability, and associated complications such as synkinesis. The selection of these measures was based on their relevance to clinical presentation and their use in prior rehabilitation research.

Statistical analysis was performed to evaluate changes over time within each group and to compare differences between groups following the intervention period. Appropriate parametric tests were applied after assessment of data distribution. A threshold for statistical significance was established a priori.

This study aims to contribute to the existing body of evidence by providing controlled clinical data on the role of sensory-based adjunct therapies in facial rehabilitation following stroke. The findings are expected to inform clinical practice by clarifying whether the addition of exteroceptive stimulation offers meaningful benefits beyond conventional physiotherapy alone. Furthermore, the study may serve as a basis for future research exploring optimized rehabilitation protocols, longer follow-up durations, and larger multi-center trials.

Inclusion Criteria:

• Patients diagnosed with post-stroke facial palsy
• Age between 40 and 55 years
• Both male and female participants
• Acute onset of facial weakness within 1-3 weeks
• Non-traumatic onset of disease
• Commitment to comply with electrical stimulation treatment

Exclusion Criteria:

• Participation in other therapies for facial nerve
• Presence of neoplastic tumor, Pregnancy, Cardiac, Excessive perspiration, Psychiatric illness or Mental impairment, Neurotmesis, Post-surgical cases of heart and brain surgery
• Bilateral facial palsy due to demyelinating disease e.g. motor neuron disease, trigeminal neuralgia, Open wounds/ulcers, ENT impairment/Otitis Media, Repetitive previous history of stroke
• Invasive cardiac instrumentation such as endarterectomy or stent placement within 30 days prior to admission in ICU were excluded