Palatal tremor, also known as palatal myoclonus, is usually seen in olivary degeneration caused by lesions in the Guillain–Mollaret triangle. We describe a 45‐year‐old woman with amyotrophic lateral sclerosis (ALS) who had palatal tremor, which is a rare association. 1 This patient who had no comorbidities or significant family history presented with asymmetric onset progressive limb weakness for 6 months. She had thinning of thigh and calf muscles and twitching movements of the thigh muscles. There were no sensory complaints, bladder, or cognitive impairment. Her vision and extra‐ocular movements were normal. She had fasciculations of the tongue (Video S1), mentalis (Video S2), and quadriceps. Tongue was atrophied (Fig. 1) as were the quadriceps, and gastrosoleus muscles. A striking examination finding was the presence of palatal tremors, which were rhythmic involuntary bilateral elevations of the soft palate and uvula at a frequency of 0.5 Hz (Video S1). There was no ocular tremor, nystagmus, or clicking sound in the ears. Her power was Medical Research COuncil (MRC) grade 4−/5 in the proximal lower limbs bilaterally and 4+/5 in the bilateral upper limbs and distal lower limbs. She had spasticity and brisk deep tendon reflexes in all limbs along with a brisk jaw reflex. Examination of her sensory, cerebellar, and extrapyramidal systems was normal.
FIG. 1.
Tongue atrophy suggesting bulbar involvement, which is commonly seen in amyotrophic lateral sclerosis.
Blood investigations showed mild anemia and subclinical hypothyroidism. Her renal and liver function tests, serum calcium, and vitamin levels (B12, D3) were normal. Antinuclear antigen was negative, and serum electrophoresis was normal. Nerve conduction study was suggestive of pure motor axonal pattern of involvement. Electromyography showed fasciculations in bulbar, cervical, thoracic, and lumbosacral spinal segments. A diagnosis of clinically definite ALS was made according to the Awaji–Shima consensus recommendations. A computed tomography scan of the thorax, abdomen, and pelvis ruled out any malignancy. Magnetic resonance imaging (MRI) of the cervical spine and cervico‐medullary junction showed no cord or radicular compression. There was no signal abnormality in the medulla. Genetic studies could not be done because of financial constraints.
She was started on Riluzole, which is a neuroprotective drug, and Edaravone, which acts as an antioxidant. However, she worsened further with the development of severe bulbar symptoms and succumbed to her illness after 8 months of the onset of her symptoms. We could not get an autopsy done for pathological diagnosis.
Symptomatic palatal tremors are usually associated with olivary degeneration. Olivary degeneration develops secondary to a lesion within the dentato‐rubro‐olivary pathway, 2 also referred to as the Guillain–Mollaret triangle. This triangle comprises the ipsilateral red nucleus in the midbrain, the inferior olive in the medulla, and the contralateral dentate nucleus in the cerebellum. 3 The major causes are cerebrovascular diseases, degenerative diseases, encephalitis, multiple sclerosis, and trauma. 2 There has also been described an idiopathic syndrome of progressive ataxia and palatal tremor. 4
ALS is a progressive neurodegenerative disease. The etiology is unknown in majority of the cases, whereas some are genetic. It is important to exclude treatable mimics such as compressive myeloradiculopathy, HIV infection, and so on.
Although not consistently seen, T2 and proton‐density magnetic resonance imaging in most cases of symptomatic palatal tremor show a hyperintense signal with or without enlargement of the inferior olive. 5 , 6 T2 hyperintensity of the corticospinal tract can be seen in the medulla in ALS, but it has to be differentiated from olivary hypertrophy. Olivary hypertrophic degeneration was seen microscopically in a few patients with ALS, although there was no associated palatal tremor. 7 , 8
Through this case, we highlight the possibility of palatal tremor associated with ALS, which is an extremely rare phenomenon. This suggests that the neurodegeneration in ALS might not be restricted to motor neurons.
Author Roles
(1) Research Project: A. Conception, B. Organization, C. Execution; (2) Manuscript Preparation: A. Writing of the First Draft, B. Review and Critique; (3) Clinical Case Management: A. Clinical Examination and Diagnosis, B: Treatment
A.R.: 1A, 1B, 1C, 2A, 3A
S.R.: 1B, 1C, 2B, 3B
D.S.: 3A, 3B
S.S.: 1C, 3A
M.K.G.: 2B
V.L.: 2B
Disclosures
Ethical Compliance Statement
No ethical issues are involved. Written informed consent from father of the patient is obtained as the patient has passed away. We, the authors confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this work is consistent with those guidelines.
Funding Sources and Conflict of Interest
No specific funding was received for this work. The authors declare that there are no conflicts of interest relevant to this work.
Financial Disclosures for the Previous 12 Months
The authors declare that there are no additional disclosures to report.
Supporting information
Video S1 Palatal tremor which is a rare phenomenon in amyotrophic lateral sclerosis is seen in the video. Fasciculations in tongue are also seen which suggest lower motor neuron involvement of hypoglossal nerve.
Video S2 The video shows fasciculations in mentalis muscle which suggest lower motor neuron involvement of facial nerve.
Acknowledgments
We acknowledge the support and motivation of Dr. Neeraj Balaini, Dr. Rajveer Singh, and Dr. Kamalesh Chakravarty in writing this article and the execution of this project.
Relevant disclosures and conflicts of interest are listed at the end of this article.
References
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Supplementary Materials
Video S1 Palatal tremor which is a rare phenomenon in amyotrophic lateral sclerosis is seen in the video. Fasciculations in tongue are also seen which suggest lower motor neuron involvement of hypoglossal nerve.
Video S2 The video shows fasciculations in mentalis muscle which suggest lower motor neuron involvement of facial nerve.