Tongue Tremor in Acute Cortical Infarct
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Day 2: Video depicting tongue tremor with selective weakness of middle, ring, and little fingers of the right hand. Tongue tremor was present during hyperextension of the neck also. Day 5: Decreased tongue tremor with improved middle finger weakness. Day 15: Disappearance of tremor with significant improvement in finger weakness.
Sanjay Pandey DM, Neelav Sarma MD and Shruti Jain MD
Article first published online: 18 DEC 2015 | DOI: 10.1002/mdc3.12288
Isolated tongue tremor has been rarely described in brainstem pilocytic astrocytoma, Wilson's disease, after gamma knife radiosurgery for acoustic schawanoma and after electrical injury. The exact pathogenesis is not very clearly described about the rhythmic movement of the tongue, but the origin has been localized to the Guillain-Mollaret triangle. We are presenting a 42-year-old person who developed tongue tremor from acute cortical infarct. This type of presentation has not been described previously, to the best of our knowledge.
A 42-year-old person presented with acute onset tremulous movement of the tongue causing difficulty in speaking and eating. The tongue movement used to disappear during sleep, but worsened while opening the mouth. His symptoms progressed over the day, when he also noticed the weakness of his right-hand grip. He was a known case of hypertension for the last 2 years without any regular treatment. On examination, the tongue was very tremulous (see Video 1). The tremor involved the entire tongue muscle, and the frequency was 4 to 5 Hz on surface electromyography. The palatal muscles were not involved. The tongue was not weak, and the tremor was not distractible. Motor examination revealed grade 2 (on medical research council grade) weakness in the right middle, ring, and small fingers (see Video 1). Deep tendon reflexes were brisk in the right upper and lower limbs.
Language, motor, sensory, and cerebellar examination was normal. MRI of the brain was suggestive of acute cortical infarct in the left frontoparietal region with no involvement of brainstem or cerebellum (Fig. 1A–F). Extra- and intracranial magnetic resonance angiography (MRA) was normal. The patient was started on tablet aspirin (325 mg), atorvastatin (40 mg), and amlodipine (10 mg). His tongue tremor started improving on day 3 and disappeared on day 5 (see Video 1).
Figure 1. On axial sections MRI of brain there are multiple areas of hypointensity in the left frontoparietal cortex on T1-weighted images (T1WI) (A). They are hyperintense on T2WI (B) and fluid-attenuated recovery (C) sequences. On diffusion-weighted images (D), they are also hyperintense, suggestive of restricted diffusion, and on apparent diffusion coefficient sequences (E), corresponding areas are hypointense. Diffusion-weighted image at the level of the medulla and cerebellum is normal (F).
Our patient presented with tongue tremor and hand weakness after an acute cortical infarct. Although tongue weakness and palatal tremor have been described after acute cortical stroke, tongue tremor has not been reported.[2, 3] The mechanism of tongue tremor in our patient may be similar to the palatal tremor or myoclonus, which has been localized to inferior olivary nucleus, but has also been reported after a cortical infarct. Epileptic palatal myoclonus and palatal tremor of cortical origin presenting as epilepsia partialis continua has also been reported.[4, 5] Further evidence of cortical involvement in palatal tremor patients has also been observed in functional MRI studies. So, the possible explanation for the genesis of the tremor in this patient could be as a result of diaschisis, where the cortical infarct may have temporarily produced dysfunctions of subcortical connections involving the dentato-rubral-olivary pathway. Another mechanism may be owing to involvement of cortico-bulbar fibers originating in the frontal cortex, but our patient did not have any weakness of the tongue. Tongue tremor in this patient is very similar to limb-shaking transient ischemic attack, where brief, jerky, and coarse involuntary movements involve an arm or leg. This condition is associated with a high degree stenosis or occlusion of the internal carotid artery, but in our patient, MRA was normal. Another interesting point to note in our patient is the rapid resolution of the tongue tremor without any specific treatment, which is contrary to the tongue tremor observed in other condition.
To conclude, this case highlights the fact that there may be a cortical role in the generation of tongue tremor.