The Movement Disorder Society

MDS Abstract of the 16th International Congress of Parkinson's Disease and Movement Disorders, Volume 27,
June 2012 Abstract Supplement

Movement Disorders 2012
Dublin, Ireland June 17-21, 2012.


Adult onset idiopathic focal lower extremity dystonia: A comparative phenomenological analysis of this novel task specific dystonia

Ramdhani,  R.A., Cho,  C., Frucht,  S.J.

Objective:

To evaluate the phenomenology of idiopathic focal lower extremity (LE) task specific dystonia and compare it to other focal task specific dystonias.

Background:

Adult onset focal lower extremity dystonia is rarely seen and usually attributed to secondary etiologies such as parkinsonism, trauma, stroke, or psychogenic. Over the last several years, there has been a number of case series that have reported an idiopathic variant triggered during ambulation.

Methods:

We present 9 patients with idiopathic focal LE dystonia and compared them to several recently published case series to further characterize the disorder.

Results:

A total of 72 patients (55 female, 17 male) were included. Of these 72 patients, 48 (37 female, 11 male) were diagnosed as having idiopathic LE dystonia. The distal extremity was affected in 36 patients, proximal extremity in 5, and both proximal and distal extremity in 7. Routine ambulatory mechanisms (e.g. standing, walking, descending stairs) were triggers for the dystonic limb posture. The average age of onset was 48 and a family history of dystonia was rare. Of 33 patients in which the side of the dystonia was known, 20 were affected on the left. Further analyses on the distal extremity involvement, showed that inversion of the foot as well as flexion of one or more toes were the most prevalent patterns. Initial presentation in fifteen patients occurred during prolonged exercising (e.g long distance running or walking) suggesting a transformation from intense exertional induced dystonia to one that is easily triggered with routine ambulation. Botulinum toxin a demonstrated a response in 14 of 27 treated patients compared to only 2 of 30 patients treated with L-dopa. When compared to other focal task specific dystonias (FTSD), the lower extremity dystonia manifested at a later age and predominantly affected females (F): Musicians Hand (36yrs/F20%), Writers Cramp (38yrs/F33%), Embouchure (36yrs/F28%), Cranial (46yrs/F43%), Lower Extremity (48yrs/F77%).

Conclusions:

Adult onset idiopathic focal lower extremity dystonia is a task specific dystonia triggered by ambulation that occurs later in life and predominantly affects females. It preferentially involves the left side with foot inversion and flexion of one or more toes being the most prevalent pattern.

Keywords :

Botulinum toxin: Clinical applications: dystonia,Dystonia: Anatomy,Dystonia: Clinical features,Dystonia: Treatment

To cite this abstract, please use the following information:
Ramdhani, R.A., Cho, C., Frucht, S.J.; Adult onset idiopathic focal lower extremity dystonia: A comparative phenomenological analysis of this novel task specific dystonia [abstract]. Movement Disorders 2012;27 Suppl 1 :1082