Spasticity and pain in adults with cerebral palsy

To evaluate whether spasticity measures are related to pain in adults with cerebral palsy (CP).

This cross-sectional study recruited individuals aged 16 to 89 years with a diagnosis of CP. Participants completed the Penn Spasm Frequency Scale (PSFS), Brief Pain Inventory (BPI), and PROMIS Pain Interference measures. The Modified Ashworth Scale (MAS) and Tardieu spasticity angles of six joints were rated and summed to composite MAS and Tardieu scores for each participant. Associations between spasticity and pain measures were evaluated.

Forty-seven participants (27 females, 20 males) with a mean age of 35 years 7 months (range 18-77y) spanning all Gross Motor Function Classification System (GMFCS) levels were included. Twenty-six participants reported their average pain level on BPI as greater than 0 over the past week (median pain level 4.0). Median PSFS was 1.0 (range 0.0-1.0) and this correlated with average BPI and Pain Interference T scores (median 40.7; ρ=0.33 and ρ=0.31 respectively [both p=0.01]). When adjusted for pain medication use and age, MAS correlated with BPI (ρ=0.30; p=0.04). Other pain and spasticity measures, or GMFCS level, were not significantly related with pain interference or BPI rating. Age was weakly associated with BPI (slope=0.10; p<0.01).

PROMIS Pain Interference was lower than population-based norms. Patient-rated spasm frequency demonstrated better association with pain levels and interference than physician-rated MAS and Tardieu.

Pain was not associated with Gross Motor Function Classification System level. Pain increased with age, as anticipated. Self-reported spasm scores were associated with increased pain in contrast to clinical examination scales. Adjusted, summed spasticity on the Modified Ashworth Scale was associated with pain scores on the Brief Pain Inventory. Although pain is experienced by adults with cerebral palsy, pain did not interfere with activities.