Isolated tongue tremor (without palatal or limb tremor) has rarely been reported in patients with Parkinson's disease; and, in those rare cases, the tremor was levodopa (l‐dopa) responsive.1, 2 To our knowledge, this the first report of an isolated tongue and jaw tremor that was not responsive to l‐dopa in a patient with progressive supranuclear palsy (PSP).
Case Report
This 82‐year‐old woman presented who had progressive parkinsonism for 8 years before evaluation, when her family noticed decreased facial expression. Thereafter, she had difficulties writing, her gait slowed, and she had decreased associated movements. A year later, she developed dysarthria and drooling. Later, she developed jaw and tongue tremor. Her balance progressively worsened. Two years later, she was diagnosed with idiopathic Parkinson's disease (PD). She was started on carbidopa/l‐dopa, which was gradually increased up to 1250 mg, with 1000 mg of entacapone, but without success in the treatment of tremor or parkinsonian features. Gabapentin (unknown dose) also had been unsuccessful in the treatment of tongue tremor. Three years before evaluation, she developed freezing and falls; she started using a cane and, later, a walker. She denied vivid dreaming, constipation, depression, and motor fluctuations. She had no previous history of trauma or exposure to psychoactive or antidopaminergic medications. There was an absence of nonmotor features, and she had no family history of tremor.
On her first examination, blood pressure was normal while lying and standing. Her Montreal Cognitive Assessment revealed mild cognitive impairment (she scored 20 of a possible 30) with prominent abnormalities in executive function. Blepharospasm, eyelid opening apraxia, vertical supranuclear ophthalmoparesis (slow hypometric vertical saccades with normal horizontal saccades and horizontal but no vertical optokinetic nystagmus), and absent convergence were noted. She had moderate‐to‐severe akineto‐rigid, symmetric parkinsonism with predominant axial involvement and a 3‐Hz to 4‐Hz jaw tremor associated with a 4‐Hz to 5‐Hz resting and postural tremor of the tongue (Video S1). Her tongue tremor was continuous and interfered with eating and speaking.
She walked with a walker and was unable to safely stand without assistance. A magnetic resonance image of her brain was normal. Her symptoms continued to slowly progress. Table 1 provides details from the initial evaluations and at the final visit 4 years later.
Table 1.
Evaluations at the first and last visits
| Clinical finding (clinical scale) | Score on item(s) | |
|---|---|---|
| First visit | Last visita | |
| Urinary problems (MDS‐UPDRS, Item 1.10) | 0 | 1 |
| Chewing and swallowing problems (MDS‐UPDRS, Item 2.3) | 0 | 2 |
| Speech problems (MDS‐UPDRS, Item 3.1) | 3 | 3 |
| Neck rigidity (MDS‐UPDRS, Item 3.3a) | 4 | 4 |
| Limb rigidity (MDS‐UPDRS, items 3.3b–3.3e) | 2–3 | 2–3 |
| Arising from chair (UPDRS, Item 3.9) | 3 | 4 |
| Gait problems (MDS‐UPDRS, Item 3.10) | 2 | 3 |
| Freezing of gait (MDS‐UPDRS, Item 3.11) | 2 | 3 |
| Postural instability (MDS‐UPDRS, Item 3.12) | 3 | 4 |
| Tremor of limbs (MDS‐UPDRS, Items 3.15a – 3.17 d) | 0 | 0 |
| Lip/jaw tremor (MDS‐UPDRS, Item 3.17e) | 2 | 2 |
| Cognitive state (MoCA) | 20/30 | 16/30 |
Abbreviations: MDS‐UPDRS, Movement Disorder Society‐Unified Parkinson Disease Rating Scale; MoCA, Montreal Cognitive Assessment.
The second visit took place 4 years after the first visit.
Discussion
This is the first report of a prominent tongue and jaw tremor without palatal and limb tremor in a patient with PSP. However, there are rare reports of palatal tremor in patients who have PSP.3 Our patient meets both the William's definition4 and the recently described probable Movement Disorder Society PSP‐parkinsonism criteria.5 She presented with a PD phenotype (bradykinesia and rigidity with axial predominance, and l‐dopa resistance; A2) that later converted into a PSP‐Richardson phenotype (clear limitation of the range of voluntary gaze in the vertical more than in the horizontal plane; O1).
Central oscillators in the Guillain‐Mollaret triangle,6 thalamus, or basal ganglia7 are thought to generate tongue tremor. We hypothesize that the mechanism of tremor in this patient may be similar to that of palatal tremor; however, here, the involvement of special, unknown regions of the red nucleus or central tegmental tracts might produce an autonomous neuronal rhythm generator in the inferior olive that only affects the group of motor neurons of the ambiguous or hypoglossal nuclei, which are responsible for tongue (and not palatal) movements.6 Although the patient's brain magnetic resonance image was normal, the areas mentioned above can be affected in PSP.8 It is likely that the involvement of unknown, rare, red nucleus or central tegmental tract areas have caused this patient's isolated tongue and jaw tremor. This type of involvement seems to be very rare, because there are no previous reports of isolated tongue and jaw tremor in patients with PSP.
An alternative possibility to consider is that this patient has both PSP and PD but does not have the typical nonmotor features of PD. Moreover, not only is the occurrence of prominent tongue tremor without limb and palatal tremor uncommon in PD; but, to our knowledge, the association of these 2 disorders is extremely rare.
Author Roles
1. Research Project: A. Conception, B. Organization, C. Execution; 2. Statistical Analysis: A. Design, B. Execution, C. Review and Critique; 3. Manuscript Preparation: A. Writing the First Draft, B. Review and Critique.
A.S.: 1C, 2A, 2B, 3A
I.L.: 1A, 1B, 1C, 2A, 2B, 2C, 3B
Disclosures
Ethical Compliance Statement: We 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: The authors report no sources of funding and no conflicts of interest.
Financial Disclosures for the previous 12 months: Ali Shoeibi reports no sources of funding and no conflicts of interest. Irene Litvan is a member of the Biotie/Parkinson Study Group Medical Advisory Board; she is a National Institutes of Health investigator supported by grants 5P50 AG005131‐31, 5T35HL007491, 1U01NS086659, and 1U54NS092089‐01; she reports support from the Parkinson Study Group, the Michael J. Fox Foundation, AVID Pharmaceuticals, AbbVie/C2N Diagnostics, and Biogen/Bristol‐Myers Squibb; and she receives a salary from the University of California‐San Diego.
Supporting information
A video accompanying this article is available in the supporting information here.
Video S1. The patient exhibits tongue and jaw tremor, but no limb tremor; vertical supranuclear ophthalmoparesis, which is characterized by upward more than downward, slow, and hypometric saccades and an absence of the saccadic phase of vertical optokinetic nystagmus; blepharospasm with eye‐opening apraxia; stooped posture; gait freezing; and axial‐predominant, akineto‐rigid symmetric parkinsonism.
Acknowledgements
We thank the patient and her family for their time and for their involvement in the project.
Relevant disclosures and conflicts of interest are listed at the end of this article.
Supporting information may be found in the online version of this article.
References
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Associated Data
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Supplementary Materials
A video accompanying this article is available in the supporting information here.
Video S1. The patient exhibits tongue and jaw tremor, but no limb tremor; vertical supranuclear ophthalmoparesis, which is characterized by upward more than downward, slow, and hypometric saccades and an absence of the saccadic phase of vertical optokinetic nystagmus; blepharospasm with eye‐opening apraxia; stooped posture; gait freezing; and axial‐predominant, akineto‐rigid symmetric parkinsonism.