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Continuous Involuntary Tut-Tutting: A Case Report

Background: What Japanese speakers refer to as shitauchi involves a tongue movement similar to what English speakers refer to as tut-tutting but has a different connotation. In the Japanese social setting, this tongue clicking is equivalent to uttering a common 4-letter English obscenity. Objective: To report a case of continuous involuntary tut-tutting caused by a variant type of rhythmic palatal myoclonus. Case Report: An 80-year-old woman visited our clinic because of continuous involuntary tongue clicking for approximately a decade that prevented her from attending most social events. It occurred while she was active during the day but not during sleep. She was in good health with no history of disease or trauma and did not smoke cigarettes, consume alcohol, or receive psychotropic medication. She had no family history of neurologic or psychiatric disorders, including a tic. During the past 10 years, she had consulted primary care physicians, neurologists, otorhinolaryngologists, and psychiatrists for her condition. Many diagnoses had been considered, including a psychogenic origin, tic, palatal tremor, and dystonic tremor, and she had many procedures, such as magnetic resonance imaging, electromyography, electroencephalography, and nasolaryngeal fiberscopy. No treatment had been attempted, in part because a diagnosis could not be established. As we observed her neck, her hyoid bone and thyroid cartilage quickly jerked upward simultaneously with the clicking sound (view Supplement Videos 1 and 2). Laryngeal fiberscopy through the nose showed that the clicking sound occurred when her tongue moved downward inside the oral cavity without contraction of the palate or pharyngeal constrictor muscles or involvement of the vocal fold or esophagus. We concluded that the mechanism involved a rhythmic myoclonic jerk of the extrinsic laryngeal and tongue muscles. Magnetic resonance imaging scans of the brain and brainstem were unremarkable. She declined further electromyographic examination. We prescribed a 2-week course of baclofen, 0.5 mg/d, to relax her laryngeal and tongue muscles, but the clicking did not decrease. We then prescribed clonazepam, 0.5 mg/d, and after 14 days, the clicking had stopped. At 1-year follow-up, the clicking has remained well-controlled by clonazepam, 0.5 mg/d, and she has been able to go to the theater, the cinema, the library, and concerts without committing the social faux pas of shitauchi. Discussion: Similar clicking sounds have been reported in cases of rhythmic palatal myoclonus. However, these cases usually were associated with hypertrophic degeneration of the inferior olivary nucleus, whereas this patient's magnetic resonance imaging scan found no evidence of that lesion (13). We believe that this patient has a variant type of rhythmic palatal myoclonus involving contraction of the hyoglossus muscle that causes movement of the tongue and hyoid bone, and we suspect that she has an unidentified brainstem lesion that led to changes in neurotransmitter mechanisms, including the -aminobutyric acid system, which are responsible for her symptoms. Clonazepam, anticholinergic agents, 5-hydroxytryptophan, l-dihydroxyphenylalanine, baclofen, piracetam, and anticonvulsants are used to treat palatal myoclonus (13). This patient's response to therapy indicates that -aminobutyric acid A rather than -aminobutyric acid B receptors were involved.