Photobiomodulation Therapy for Symptom Management in Essential Palatal Myoclonus: Two Case Studies with Long-Term...

Palatal myoclonus (PM) is a rare movement disorder characterized by involuntary rhythmic contractions of the soft palate and adjacent musculature. Conventional therapies, including pharmacologic agents and botulinum toxin injections, frequently provide inconsistent or temporary relief and may be associated with adverse effects. This report evaluates photobiomodulation therapy (PBMT) as a noninvasive neuromodulatory treatment.

The two cases were managed by different clinicians in separate clinical settings under standardized protocol guidance from the primary author, allowing assessment of inter-operator reproducibility. Two patients with essential PM were treated using near-infrared diode laser PBMT. Case 1: A 26-year-old female presented with persistent PM (2.5 Hz) accompanied by dysphagia, audible clicking, and sleep disturbance. Pharmacotherapy (clonazepam and gabapentin) was discontinued due to intolerance. PBMT using a 940 nm diode laser (8.7 J/cm²) was applied over 20 sessions. Case 2: A 28-year-old male developed PM-like symptoms (3 Hz) following third molar extraction, associated with clicking, migraine, and myofascial pain. Neurological investigations were inconclusive. PBMT with a 980 nm diode laser (13.3 J/cm²) was administered over 2-month period.

In Case 1, contraction frequency decreased from 2.5 Hz to 0.11 Hz after treatment and remained stable between 0.12-0.36 Hz over a 7-year follow-up, with marked improvement in swallowing and sleep quality. In Case 2, contraction frequency decreased from 3 Hz to 0.3 Hz within 60 days, accompanied by functional and symptomatic improvement.

Near-infrared PBMT produced a substantial and sustained reduction in PM activity without adverse effects. Comparable outcomes using 940 nm and 980 nm wavelengths suggest a neuromodulatory rather than purely tissue-heating mechanism.

PBMT may represent a safe and repeatable treatment option for essential PM, a condition with limited effective therapies. Controlled clinical studies are required to confirm optimal parameters and long-term efficacy.