Striking Alleviation of down the Stairs Dystonia by Ankle Tightening

Stair‐specific (ascending and descending) dystonia is a rare type of task‐specific lower limb dystonia that manifests dystonic symptoms when going either up or down the stairs. ¹ Sensory trick is an alleviating maneuver that temporarily improves dystonic symptoms. ² Because the effects of most sensory tricks on dystonia are transient, they are usually not used as treatments in clinical practice. We report a case in which descending stair‐specific dystonia was alleviated by sensory trick involving tightening of the affected ankle.

The patient was a 17‐year‐old woman with no family history of movement disorders. At age 11, she developed involuntary left hip adduction while ascending stairs only. One year later, she developed involuntary abduction of the left hip joint and involuntary flexion of the left knee only while descending stairs. Her walking on level ground was normal. The involuntary movement in her left foot gradually worsened and severely interfered with descending stairs (Fig. 1A, Video 1). She was prescribed trihexyphenidyl (3 mg/day), clonazepam (2 mg/day), and zolpidem (10 mg/day), based on a neurologist's diagnosis of focal foot dystonia. However, they were ineffective in alleviating symptoms. Botulinum toxin injections were not attempted due to their high cost and because they are not covered by the Japanese health insurance for the treatment of foot dystonia. She was referred to our hospital for surgical treatment at age 17. She had no history of left‐foot injury and psychiatric disorders. There were no abnormal findings on head magnetic resonance imaging or laboratory test results. Genetic screening of DYT genes did not detect genetic mutations related to hereditary dystonia. Neurological examination results were unremarkable. We scheduled radiofrequency ventro‐oral thalamotomy for focal foot dystonia. However, the patient incidentally noticed that tightening of the left foot just superior to the level of the malleolus (Fig. 1B) markedly improved external rotation in the left foot while descending the stairs (Fig. 1C, Video 1). Weak force tightening of the ankle did not improve symptoms; however, tightening with relatively strong force improved dystonia symptoms. Due to improvement of the dystonia while descending the stairs, the patient canceled the surgery. Six months after the ankle tightening started while descending stairs, the dystonic symptoms from before were clearly relieved, even without ankle tightening (Video 2 ).

FIG. 1.

Sensory trick for focal foot dystonia while descending stairs. (A) Involuntary left hip abduction and involuntary left knee flexion while descending stairs. (B) Tightening of the left ankle as a sensory trick. (C) Dystonic symptoms alleviated with sensory trick.

Video 1.

Dystonic symptoms while walking downstairs are strikingly alleviated by tightening the left ankle.

Video 2.

Significant improvement of dystonic symptoms 6 months after the start of the ankle tightening.

Sensory tricks are observed in approximately three‐quarters of patients with adult‐onset focal dystonia. ¹ Several studies have reported the sensory trick phenomenon for ascending or descending stair‐specific dystonia, such as backwards walking, walking down sideways, or imagining walking down backwards. Most cases of ascending or descending stair‐specific dystonias do not respond well to botulinum toxin injections or other medications, including trihexyphenidyl, levodopa, carbamazepine, and tetrabenazine. ³ , ⁴ Radiofrequency ablation of the ventro‐oral nucleus of the thalamus is effective for focal foot dystonia. ⁵ Since focal lower limb dystonia is more common among those in their 40s and spontaneous resolution is rare, the possibility of a diagnosis of functional dystonia cannot be ruled out in this case. Noninvasive treatment with sensory tricks is a treatment option worth considering for focal dystonia.

Author Roles

(1) Research project: A. Conception, B. Organization, C. Execution; (2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; (3) Manuscript Preparation: A. Writing of the first draft, B. Review and Critique.

SH: 1A, 1B, 1C, 3A, 3B.

TK: 1B.

TT: 1A, 1B, 1C.

Disclosures

Ethical Compliance Statement: The authors confirm that the approval of an institutional review board was not required for this work. Written and verbal informed consent from the patient was obtained. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this work is consistent with those guidelines.

Funding Sources and Conflicts of Interest: This work was supported by JSPS KAKENHI Grant Number JP21K09113. The authors declare that there are no additional disclosures to report.

Financial Disclosures for the Previous 12 Months: The authors declare that there are no additional disclosures to report.