a 16-year - old boy visited to our neurology clinic with a 12-month history of a clicking noise in the both ears and palatal discomfort .
the clicking resembled the sound of snapping fingernails and was externally audible at a distance of 50 cm .
he denied any voluntary control over this movement as well as any sensation of urge before the movement .
he complained of throat fullness in daytime . on neurologic and otolaryngologic examination , rhythmic contraction of whole soft palate muscles
the movement was able to be suppressed for a few seconds by touching the back of his neck , but it could soon return after the voluntary suppression .
in addition , the entrainment at each slow and fast finger tapping with external pace was found ( video ) .
needle electromyography ( emg ) of tvp muscle showed rhythmic contractions with a frequency of 2.6 hz with amplitude of 150 v ( figure 1 ) .
there were no abnormal results in other laboratory , audiologic tests , and brain magnetic resonance imaging .
after diagnosis of ept , despite of medications including benzodiazepines , muscle relaxants , and anticonvulsants for 1 month , his symptoms were not changed at all .
therefore , we started to inject 15 units of bta ( botox , allergan , inc . ,
though the success of the first bta therapy was lasted about 10 weeks , the additional injections of bta were needed for 3 times due to recurrence .
the dosage of bta was finally elevated to 20 units and there were 4 times injection of bta at interval of 3 months , but the presenting symptoms showed again .
his involuntary movements were clinically closed to ept because of ear click perceived as objective tinnitus , bilateral involvement , no brain lesions and involvement of tvp muscle by emg . although no single clinical finding is pathognomonic for pmds , several features are quite helpful.10 in general , pmds are characterized by distractibility , entrainment , coactivation sign , variable frequency , amplitude and direction , increase with attention , and poor response to medications.8,11 this patient also showed entrainment of soft palate muscle contraction to external paced finger tapping .
furthermore , pmds have particular histories including precipitating factor or trivial trauma preceding acute onset , emotional trigger , psychological stressors and psychiatric comorbidities such as anxiety disorders.8 in this patient , mild trauma ( e.g .. voice abuse ) before onset suggest to psychogenic type of ept rather than primary type . in our case ,
the only difference from usual psychogenic pt is that this abnormal movement was not well responded to treatment .
psychogenic pt is usually reported to have good response to non - physiological treatment or placebo.8 in summary , bilateral objective tinnitus , bilateral tvp muscles involvement , mild trauma before onset , and entrainment of soft palate contraction suggest a psychogenic ept .
 essential palatal tremor ( ept ) is a rare disorder which shows rhythmic involuntary movement of the muscles of soft palate , especially tensor veli palatini muscle . 
 ept is classified by two subtypes , which is primary and secondary ept . 
 secondary ept includes psychogenic type . 
 we describe a case of intractable psychogenic ept . 
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