Objective: To report a case of both Multiple System Atrophy (MSA) and Palatal Myoclonus (PM) suggesting that PM can be associated with neurodegeneration.

Background: PM is a phenomenon of brief, involuntary jerks of the muscles of the palate. Cases are most commonly secondary to a lesion within the Guillain-Mollaret triangle. However, 3% of cases have been associated with neurodegenerative diseases [1]. MSA is a neurodegenerative disease from alpha-synuclein aggregation and consists of clinical features of parkinsonism, cerebellar ataxia, and autonomic failure. Here, we present the first case of PM thought to be secondary to MSA.

Method: Case report

Results: 70-year-old man presented with chronic palatal twitches as well as orthostatic hypotension and progressive gait instability. Examination was notable for hypernasal voice, anterocollis, bradykinesia, axial rigidity, and limb and axial ataxia, which are characteristic features of MSA. Palatal jerks also seen on examination were consistent with PM. There were no contributing vitamin deficiencies or metabolic derangements. Genetic ataxia panels were negative. MRI brain with thin cuts was unremarkable. Skin biopsy was positive for alpha synucleinopathy. He had no response to levodopa. With his clinical evaluation, poor levodopa response, and skin biopsy, the patient was diagnosed with clinically probable MSA and PM.  Patient declined treatment for his PM as it did not bother him. His MSA was treated with physical therapy, botulinum toxin for cervical dystonia, and supportive care.

Conclusion: Most cases of PM are caused by a lesion within the Guillain-Mollaret triangle however this was not true in our case. To our knowledge, this case is the first of PM found to be secondary to MSA. The pathophysiology of non-lesional PM is unclear. We hypothesize that the olivopontocerebellar degeneration in MSA can cause PM as this region is within the Guillain-Mollaret triangle. Though progressive ataxia and palatal tremor was a consideration, this condition is a taupathothy [3] whereas our patient had evidence of alpha synuclein pathology as well as supportive clinical signs of MSA.

Our case of MSA-associated PM shows that recognition of PM should prompt an evaluation for neurodegenerative disease if no structural lesion is found. Though PM in neurodegenerative disease is rare, this association is important to keep in mind to guide evaluation.

References: 1. Michael Samuel, Nurhan Torun, Paul J. Tuite, James A. Sharpe, Anthony E. Lang, Progressive ataxia and palatal tremor (PAPT): Clinical and MRI assessment with review of palatal tremors, Brain, Volume 127, Issue 6, June 2004, Pages 1252–1268, https://doi.org/10.1093/brain/awh137
2. Deuschl G, Mischke G, Schenck E, Schulte-Mönting J, Lücking CH. Symptomatic and essential rhythmic palatal myoclonus. Brain. 1990 Dec;113 ( Pt 6):1645-72. doi: 10.1093/brain/113.6.1645. PMID: 2276039.
3. Marrakchi S, Laasri K, Moufakkir R, Guelzim Y, Hadj Hsain I, El Yousfi Z, Fenni JE, En-Nouali H. Progressive ataxia and palatal tremor (PAPT) with hypertrophic olivary degeneration (HOD): A case report. Radiol Case Rep. 2024 Mar 20;19(6):2264-2267. doi: 10.1016/j.radcr.2024.01.054. PMID: 38544788; PMCID: PMC10965476.
4. D. Riley. Nomencladventure: Palatal myoclonus and palatal tremor [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/nomencladventure-palatal-myoclonus-and-palatal-tremor/. Accessed March 02, 2025.

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