To evaluate common phenotypes of tonic spasms (TS) in patients with spasticity and inform therapeutic interventions

Spasticity can be associated with several hyperkinetic involuntary movements, most commonly TS. The phenomenology and location of these spasms can guide therapeutic interventions. The prevalence and treatment-responsiveness of the different TS phenotypes have not been studied in a systematic manner.  

A consecutive patient sample was prospectively recruited from a specialized spasticity management clinic. All patients were assessed for spasticity-associated involuntary movements including stereotypic TS. TS were differentiated from all other involuntary movements based on previously-published criteria. Patients with demyelinating diseases – in whom tonic spasms can exist without tonic spasticity- were excluded from this analysis and will be reported separately in a future comparative study. Treatment-responsiveness was assessed from each patient. This study is still ongoing.  

This interim analysis included 48 consecutive patients with spasticity (mean age 50 +/- 14 years, 50% female) due to stroke (50%), HSPP (14.5%), spinal cord injury/compression (12.5%), and miscellaneous causes (23%). TS were present in 69% of the patients and the most prevalent phenotypes were isometric lower-extremity spasms (44%) followed by knee extensor spasms (33%), isometric upper-extremity spasms (12.5%), flexor hip (8%), adductor hip (8%), isometric truncal (8%), flexor elbow (4%), flexor knee (4%), dorsiflexor ankle (4%), adductor ankle (4%), flexor toes (4%), and 1 (2%) of each of the following: extensor hip, ankle, and toe spasms. The average Penn Spasm Frequency Scale of the study population was 1 (range 0 to 4). Therapeutic plan generally followed a 3-step-escalation involving oral agents, botulinum toxin, and intrathecal baclonfen pump, and resulted in significant improvement of spams in 27% of patients, partial improvement in 48%, and no improvement in 21%.

TS are common in patients with spasticity and have stereotypic phenotypes that can guide therapeutic interventions.