Volume 4, Issue 4 , Pages 155-157, December 2009
Objective tinnitus secondary to voluntary palatal myoclonus
Article Outline
Summary
Palatal myoclonus is a known entity causing objective tinnitus but is involuntary in most of the cases. The aim of this case report is to highlight the importance of knowing that certain palatal myoclonus can be voluntary especially in children. The tinnitus disappeared after the contraction of palatal musculature was under controlled by the patient. It is important to identify voluntary palatal myoclonus since it can be successfully treated.
Keywords: Tinnitus, Palatal myoclonus, Voluntary
Introduction
Palatal myoclonus is a condition characterized by an involuntary rhythmic contraction of the palatal musculature secondary to spontaneous spasm of Eustachian tube muscles [1]. Although an objective tinnitus secondary to involuntary palatal myoclonus is a known entity, but it is relatively rare. We present an unusual case of similar presentation but which was voluntarily induced.
Case report
A 9-year-old Malay schoolboy presented with nasal obstruction and intermittent noisy sound in his left ear for one-month duration. Rhinologic examination showed an inflamed turbinates and presence of thick nasal discharge. Endoscopic examination revealed a rhythmic movement of his left soft palate and an enlarged adenoid. However, the adenoid did not encroach the opening of the Eustachian tube. The tinnitus was clearly audible to the examiner. Its frequency was 60–70 clicks per minute but did not correlate with patient's pulsation. No nystagmus and no other abnormal movement in the other part of the body were seen. The results of otologic, head and neck and cardiovascular system were normal.
The tympanogram, middle ear reflexes, pure tone audiogram and brain stem evoked responses generated normal results. The sonotubometry was not available. Otoacoustic emission could not be obtained for the left ear because the intensity of emission saturated the microphone, preventing any measurement of the signal. MRI of the brain showed no abnormality. The patient and his parent then were explained regarding the reason for the tinnitus and his upper respiratory tract infection was treated.
Two weeks later, on follow-up, the nasal blockage, clicking tinnitus and palatal myoclonus completely disappeared. The nasal airways were patterned and adenoid was not inflamed. However, the patient seems to be able to induce and discontinue the palatal myoclonus at will by concentrating his though to the left ear. The audible tinnitus which correlates to the movement of his soft palate can be recorded at his left ear. No other physical sign was detected to suggest the cause of his tinnitus. On further probing on the general history of the patient did not reveal any cause of possible secondary gain. He was seen again after a month. No new findings were noted and he is still able to induce the palatal clonus. Parent and patient were counseled regarding the physiology of hearing and the possible cause of his OT. They seem to be satisfied with the explanation. Diagnosis of essential palatal myoclonus was made and other than reassurance to parent, no intervention was done.
Discussion
Objective tinnitus (OT) is a rare occurrence in children and much more difficult to document as compared in adults [2]. The cause of OT can be vascular pulsation or muscular contraction. Vascular OT can be either arterial or venous in origin. Muscular contraction includes palatal myoclonus (PM), myoclonus of the tensor tympani, and myoclonus of the stapedius muscle. However, only myoclonus of palatal muscles gives rise to a loud clicking noise [3]. Palatal myoclonus is most often associated with OT. Possible etiologies of palatal myoclonus include multiple sclerosis, vascular lesion in central nervous system, head trauma, meningitis, carbon dioxide poisoning, congenital nystagmus, acute rheumatism and electric shock [4].
According to Fritsh et al. [2], until year 2003, only 12 documented palatal myoclonus cases in children in English literature. He reported five cases of tinnitus in children resulting from audible spontaneous otoacoustic emissions (SOAE), palatal myoclonus, arteriovanous malformation and audible SOAE secondary to acoustic neuroma. Except for patient with arteriovenous malformation, other patients have normal otologic examination findings, tympanogram, pure tone threshold and speech audiometric test. The patient's parent received extensive counseling regarding auditory physiology, the nature of outer hair cell function and SOAE. One patient who has PM together with seizures and abnormal eye blink was prescribed with Devalproex sodium and resulted in remission of symptoms.
To reach the diagnosis of objective tinnitus in children, Fritsh et al. [2] advocate taking a thorough history with open, non-leading questions that allow the child to describe the symptom without bias. The otologic, head and neck should be examined. Audiologic evaluation should include immitance, audiometric testing and real ear recording. The child should received referrals for radiologic studies and neurologic examination, particularly if the results of otolaryngologic and audiologic evaluation are considered normal.
Report on patient with voluntary palatal myoclonus is even scarce. Literature search through Medline reveal only 3 of such reports [4], [5], [6]. Seidmen et al. [4] presented a 39-year-old man who was able to control his OT and frequencies of his palatal myoclonus. The authors claimed that they are the first to report the case of voluntary myoclonus. In his case, PM ceased spontaneously after four months. His patient learned how to open and close his Eustachian tubes while scuba diving 15 years earlier. Since then he is able to produce objective tinnitus.
Nabuo et al. [6] reported a 27-year-old man who was able to induce his OT and myoclonus at will. The man presented with nasal obstruction and postnasal discharge. The symptoms disappeared after courses of treatment, however he experienced unconscious movements of soft palate and OT soon afterward. The patient later noticed that he can voluntarily induce PM and OT by focusing his attention on his throat. His otorhinolaryngogical examination and tympanometry test showed no abnormality.
Our patient presentation resembled Nabuo's patient. However, Nabuo did not mention whether his patient has enlarged adenoid or not. We believe the adenoid did not contribute to the cause of OT as it did not encroach the Eustachian tubes opening. It is quite common to find an enlarged adenoid at our patient age. Our patient denied the history of persistent nasal blockage or snoring prior to the date of his presentation to us. Furthermore an enlarged adenoid causing OT was not reported in literature, therefore adenoidectomy was not done on him. Since there were no detectable neurological abnormalities, he was diagnosed as having essential palatal myoclonus with OT. The cause of the clicking tinnitus is the contraction of levator veli palatini muscle [7], [8]. However other authors believe the clicking noise to originate from rhythmic opening and closing of the Eustachian tube [9].
Even though palatal myoclonus is involuntary in most of the time, but one should know that it can be occasionally voluntary in certain patients. This group of patients needs to be determined since they can be treated simply by adequate reassurance.
References
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- . Objective tinnitus in children. Otol. Neurotol. 2001;22:644–649
- . Objective tinnitus of vascular origin with hearing improvement after treatment. Am. J. Otol. 1990;11:437–443
- . Palatal myoclonus as a cause of objective tinnitus: a report of six cases and a review of the literature. Ear Nose Throat J. 1999;78:292–297
- . Objective tinnitus due to clonus of the soft palate. Acta Otolaryngol. 1954;116(Suppl.):39–45
- . A case of voluntary palatal myoclonus with ear click: relationship between palatal myoclonus and click. Eur Neurol. 2002;48:52–53
- . Ear clicks in palatal tremor caused by activity of the levator veli palatini. Neurology. 1996;46:1168–1169
- . Tinnitus and myoclonus. J. Laryngol. Otol. 1972;86:237–241
- . Sonotubometry in the investigation of objective tinnitus and palatal myoclonus: a demonstration of Eustachian tube opening. J. Laryngol. Otol. 1986;100:529–531
PII: S1871-4048(08)00075-0
doi:10.1016/j.pedex.2008.11.002
© 2008 Elsevier Ireland Ltd. All rights reserved.
Volume 4, Issue 4 , Pages 155-157, December 2009
