Author:  Dr. Sudhakar Vaidya,* Dr. (Col.) G. Vyas, **, Dr V K Rawat***, Dr. Satyendra Sharma****
*Associate Professor of ENT **, Professor of Medicine***, Assistant Professor of Medicine, Assistant Professor of Medicine,****   R.D. Gardi Medical College, Ujjain (MP) India
 

Abstract:  A patient with palatal myoclonus is presented and the medical literature reviewed.  The manuscript's video showing the examination of the patient's soft palate revealed a contraction rate of 2.5 Hz.   

Introduction:  Palatal Myoclonus is a regional disorder characterized by involuntary rhythmic jerky movements of the soft palate.   “It is also known as “palatal tremor” or “palatal nystagmus” and it is a type of segmental myoclonus, 1, 2 which manifests with a frequency of 1.5 – 3Hz”.3,4  Palatal myoclonus is exceptional among movement disorders because of its persistence during sleep and frequently lacks of modulation by voluntary influences.  The youngest reported case is 18 months and the oldest is 91 year old.  Patients with palatal myoclonus complain of hearing a clicking sound, which may be perceived by the examiner by placing a stethoscope over the patient’s ear3 (objective tinnitus).

Palatal myoclonus can be cause by lesions which interrupt specific neurological pathways (lateral superior cerebellar peduncle, brachium conjunctivum and dentate nucleus ). 1,4-6   This circuit is called the triangle of Guillain and Mollaret.

Case Report:  A 35 year old male came into the ENT OPD in our hospital with complaints of an annoying noise in both ears(tinnitus) during the past one year. The noise was heard continuously by the patient & resembles the clicking of a clock. There were no other neurological symptoms.   The frequency of contractions in this patient was approximately 2.5 Hz or 150 per contractions per minute. 

On examination, the patient’s general appearance was normal.  Systemic examinations were also within normal limits, except the continuous rhythmic movement of the soft palate.  This contraction was accompanied by an audible click, which was heard by the examiner when a stethoscope was placed on the patient’s ear.  Laboratory test included CBC, ESR, LFT, RFT, lipid profile, urine analysis, thyroid function test, VDRL, RBS and electrolytes were normal.  Audiometric examination and MRI skull were also within normal limits.   A diagnosis of essential palatal myoclonus was made.  The patient was treated with clonezepam and improved significantly.

Discussion:   Palatal myoclonus is of two types:  Primary or essential, and secondary.  Possible etiologies of secondary palatal myoclonus include multiple sclerosis, cerebrovascular lesions, head trauma, meningitis, carbon monoxide poisoning, congenital nystagmus, acute rheumatism and electric shock.  The cause of the clicking tinnitus is the contraction of the levator veli palatini muscle.7-9   However, other authors believe that the clicking noise originates from rhythmic opening and closing of the eustachian tube.10   Tests recommended in all patients with palatal myoclonus are:

1. MRI of the brainstem with gadolinium
2. Physiological recordings of palate and vocal cord.
3. Video stroboscopy obtained in voice lab
4. Electromyography, Electroencephalography & SSEP (Somatosensory Evoked Potential)

In this patient, considering the rhythmic myoclonic contraction of the soft palate and the presence of a click audible by the examiner, a diagnosis of palatal myoclonus was made.

The drugs used for treatment of palatal myoclonus are clonazepam, sodium valproate, tetrabenazine, haloperidol, trihexyphenidyl HCL and carbamazepine.  Surgical treatment for essential palatal myoclonus has not been favorable.   Symptomatic palatal myoclonus usually does not respond to treatment.  In reported papers, only about 20% of treatments have been successful, but some authors indicate that no treatment is effective.

References:

1. Adam R, Victor M, Ropper AH. Principles of Neurology. 6th ed. New York: Mc Graw Hill; 1997: 101 – 2.

2. Joynt RY. Clinical Neurology. Vol 2. Rev ed. Pennsylvania: Lippincott-Raven; 1995: Chap 15, 25.

3. Bradly WG, Daroff RB, Fenichel GM, Marsden CD. Neurology in Clinical Practice. 2nd ed. Boston: Butterworth-heineman; 1996:1762-3.

4. Jnankvie J, Tolosa E. Parkinson’s Disease and Movement disorders, 2nd ed. Baltimore: Williams and Wilkins, 1993: 318-9.

5.  Bhadauria, S and Sarma YS  Case of Objective Tinnitus.  MJAFT 2005; 61:391-392.    View Article

5. Fahn S, Greene PE, Ford B, Bressman SB. Handbook of Movement disorders. 1st ed. Philadelphia: Blackwell science, 1998: 111, 115-116.

6. Seidman MD, Arenberg JG, Shirwany NA. Palatal myoclonus as a cause of objective tinnitus: a report of six cases and a review of the literature. Ear Nose Throat J. 1999 Apr;78(4):292-4, 296-7.   View Abstract

7. Jamieson DR, Mann C, O'Reilly B, Thomas AM. Ear clicks in palatal tremor caused by activity of the levator veli palatini. Neurology. 1996 Apr;46(4):1168-9.  View Abstract

8. Kwee HL, Struben WH. Tinnitus and myoclonus. J Laryngol Otol. 1972 Mar;86(3):237-41.    View Abstract

9. Slack RW, Soucek SO, Wong K. Sonotubometry in the investigation of objective tinnitus and palatal myoclonus: a demonstration of eustachian tube opening. J Laryngol Otol. 1986 May;100(5):529-31.  View Abstract

Acknowledgment: Authors are grateful to Dr. V K. Mahadik, Medical Director, R.D. Gardi Medical College & Ujjain Charitable Trust Hospital Ujjain (MP) for giving us permission to publish this research paper and for encouragement and support.  
 


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