Palatal Tremor – Pathophysiology, Clinical Features, Investigations, Management and Future Challenges

Shakya Bhattacharjee

Palatal Tremor – Pathophysiology, Clinical Features, Investigations, Management and Future Challenges

Tremor and Other Hyperkinetic Movements

Volume 10 (2020): Issue 0

By: Shakya Bhattacharjee

Open Access

|Oct 2020

Figures & Tables

The Guillain-Mollaret Triangle (1A-schematic in the left and coronal Magnetic resonance imaging on the right-1B) -formed by the Red Nucleus (RN), Dentate Nucleus (DN) of the Cerebellum, Inferior Olivary Nucleus (ION), SCP – Superior Cerebellar Peduncle (connects the DN to the RN), ICP – Inferior Cerebellar Peduncle (connects the DN to the ION), CTT – Central Tegmental Tract (connects RN to the ION).

Table 1

Causes of palatal tremor.

Symptomatic palatal tremor
I) Vascular/Ischemic:
Basilar artery occlusion [36] Brainstem or cerebellar infarct/bleed/tumor Vertebral artery dolichectasia [37] Vascular malformation (Arteriovenous malformation, aneurysm) [24 25 26 27 28 38]
II) Inflammatory/Demyelinating:
Multiple Sclerosis [39 40] Neurosarcoidosis [41] Multifocal Leukoencephalopathy Bechet’s disease [42]
III) Genetic:
Spinocerebellar ataxia [18 43]
IV) Infectious:
Tick-borne meningoencephalitis/Listeria encephalitis [44 45] Whipple disease [46]
V) Neoplastic:
Intestinal lymphoma [47] Posterior fossa tumour
VI) Neurodegenerative:
Progressive supranuclear palsy [48]
VI) Miscellaneous:
Traumatic brain injury [49] Amyotrophic Lateral Sclerosis [50] Drugs (Ciprofloxacin/Lithium/Carbamazepine) [51 52] Epilepsy [53] Hashimoto encephalopathy [54 55] Anti -GAD antibodies mediated encephalitis [56]
Progressive Ataxia and Palatal Tremor (PAPT)
I) Sporadic:
Tauopathy [7] Gluten sensitive ataxia [33] Vascular malformation [57]
II) Familial/genetic:
Alexander disease [58 59] Spinocerebellar Ataxia –20 (SCA 20) [60 61] POLG mutation [62 63] Hereditary spastic paraparesis type 7 (HSP-7) [64 65] GM2 Gangliosidosis [66] Neuroferritinopathy [67] Cerebrotendinous Xanthomatosis [68]

Table 2

Additional clinical features of various subtypes of palatal tremor.

Essential Palatal Tremor
Audible ear clicking [3 23]
Symptomatic Palatal Tremor [6 23 24 25 26 27 28]
Holmes tremor Oromandibular tremor Myoclonus Ataxia Nystagmus Dysarthria Dysphagia Throat clicking Ophthalmoplegia Optic atrophy Ocular tremor Facial myokymia Epilepsy partialis continua Intranuclear ophthalmoplegia
Progressive Ataxia and Palatal Tremor (PAPT) [7 10 28 58 59 60 61 62 63 64 65 66 67]
Pendular nystagmus/oscillopsia Hypermetric and hypometric saccades Ophthalmoplegia Optic atrophy (SPG 7, POLG mutation) Movement disorders (chorea, dystonia, parkinsonism, myoclonus – SPG 7, SCA 20, Neuroferritinopathy, POLG mutation) Pyramidal tract signs (hemiparesis, paraparesis – SCA 20, SPG 7 mutation) Neuropathy (SPG 7, POLG) Cognitive impairment (POLG mutation, Alexander disease, Neuroferritinopathy) Seizure (POLG mutation, Alexander disease) Hearing loss (mainly in sporadic PAPT) Muscle disorders (POLG mutation) Dysarthria Dysphonia (SCA 20) Dysphagia Dysmorphic feature (GM2 Gangliosidosis) Macrocephaly (Alexander disease) Diarrhea (celiac disease, GM2 Gangliosidosis) Hypogonadism, stroke like episodes (POLG mutation)

[i] Abbreviations:

EPT: Essential palatal tremor.

SPT: Symptomatic palatal tremor.

PAPT: Progressive ataxia and palatal tremor.

SPG 7: genetic mutation responsible for hereditary spastic paraparesis.

SCA 20: Spinocerebellar ataxia 20.

POLG: Polymerase gamma gene.

Table 3

The differences among the various subtypes of palatal tremor.

	Essential Palatal Tremor (EPT)	Symptomatic Palatal Tremor (SPT)	Progressive ataxia with Palatal Tremor (PAPT)
Main muscle involved in the generation of tremor [3 23]	Tensor veli palatini	Levator veli palatini	Levator veli palatini
Nerve supply of the main muscle [3 23]	5%^th cranial nerve	9%^th and 10%^th cranial nerves	9%^th and 10%^th cranial nerve
Abnormal reflex types [23]	Polysynaptic	Monosynaptic, oligosynaptic and polysynaptic	Not known
Relationship with sleep [23]	Disappears in 50% cases	Persists	Persists
Effect of anaesthesia on tremor	disappears	persists	Not known
Auditory signs	Audible ear click -Common	Audible ear click-rare	Tinnitus, sensorineural hearing loss Audible ear click – rare (familial)
Ocular signs	Rare	Can be seen	Torsional and horizontal nystagmus, INO, hypermetric saccades, reduced VOR, vertical gaze palsy, optic atrophy
Other clinical features	Rare except the ear click, entrainment common	Ataxia, tremor, dysarthria etc – not entrainable	Familial PAPT – additional pyramidal tract signs like tetraparesis, progressive ataxia, chorea, dystonia, cognitive impairment, autonomic dysfunction, tendon xanthoma Sporadic PAPT: dysarthria, dysphagia
Cause	Unknown	Sporadic -any Lesion (infarct, bleed, tumour etc) within the Guillain Mollaret triangle of brainstem or idiopathic/neurodegenerative	Familial/genetic – (POLG mutation, Alexander disease, Celiac disease, Cereberotendinous Xathomatosis, Celiac disease, GM2 Gangliosidosis) Neuroferritinopathy Sporadic-Neurodegenerative/tauopathy/MSA/Gluten sensitive
Magnetic resonance imaging of brain	No structural deficit	Hypertrophic olivary degeneration of medulla	Familial -significant brainstem atrophy but no HOD, dark dentate nucleus, cerebellar atrophy, iron accumulation in basal ganglia (Neuroferritinopathy) White matter lesion with frontal predominance (Alexander disease) Sporadic PAPT-HOD