Focal Task-Specific Lower Limb Dystonia Only When Walking Stairs: Is It a New Disease Entity?

Abstract

Introduction: Focal task-specific dystonia in the lower limb or foot often occurs only during walking, running, hiking, or cycling. Several medications and botulinum toxin injection are effective in patients with this disorder. The objective of this study was to understand the spectrum of focal task-specific dystonia in the lower limb only when walking stairs and to compare other types of task-specific dystonia.Methods: All original articles and case reports were collected and reviewed using PubMed. In addition, all video clips of published cases were evaluated, and patients' clinical findings analyzed. The present study included 12 patients described in previous studies and five new Asian patients found in the medical records.Results: Most of the patients were women, and the onset age was 42 years. Ten patients were classified as the Kicking type, including three patients with the rKicking type, and six patients were considered as the Lifting type; however, only one patient was not included in any of the types. Symptoms in most of the patients did not improve with any medications or botulinum toxin injection. The symptoms of most patients did not change over a long time.Conclusion: Most patients showed the dystonic symptom when walking downstairs rather than upstairs. Psychogenic dystonia is a disease differentially diagnosed with this dystonia. Unlike other types of focal task-specific dystonia, the response to treatment was disappointing because most of the medications and botulinum toxin injection were not effective. The prognosis is completely different from that of other types of focal task-specific dystonia.

Adult‐Onset Idiopathic Lower Limb Dystonia during Stair Descent Treated with Botulinum Toxin Injection

“…In most of these cases, the dystonia was predominantly induced by movement such as walking 1 . Much rarer is dystonia of the legs that appear only when using the stairs, which has been reported in literature as a type of focal task‐specific LLD 2 . A total of 17 cases of LLD when using the stairs have been reported in literature, and 15 of those cases had dystonia on stair descent, 1 during ascent, and 1 on ascent and descent 2 .…”

“…2 A total of 17 cases of LLD when using the stairs have been reported in literature, and 15 of those cases had dystonia on stair descent, 1 during ascent, and 1 on ascent and descent. 2 Two types were recognized, kicking and lifting. 2 The kicking type involves knee extension during hip flexion, which is similar to our patient, whereas the lifting type is characterized by knee hyperflexion during hip flexion.…”

“…2 Two types were recognized, kicking and lifting. 2 The kicking type involves knee extension during hip flexion, which is similar to our patient, whereas the lifting type is characterized by knee hyperflexion during hip flexion. 2 Three of the 17 patients were treated with BoNTA injections; however, the specific muscles injected not identified.…”

“…2 Three of the 17 patients were treated with BoNTA injections; however, the specific muscles injected not identified. 2 Unfortunately, the patients did not improve with BoNTA injection. 2 A summary of similar cases of LLD published in literature are tabulated for comparison (see Table 1).…”

An unusual cause of difficulty in walking downstairs: Focal task‐specific dystonia in the lower limb

“…Stair‐specific FTSD is a rare clinical entity. Most patients show dystonic posture when walking downstairs, and two phenotypes (kicking and lifting type) have been described 1,2 . Pharmacological intervention usually fails, but the symptoms remain unchanged over a long time.…”