Natural history of novel bulbar clinimetric scale in respiratory or nutritional device support-free ALS patients followed prospectively over 12 months.
Facial muscle strength scales are well developed in plastic surgery but simple clinimetric bulbar scales are not well established.
Forehead wrinkling/eye closure/pursing lips/puffing out cheeks/platysma contraction/clinically assessed tongue strength was rated [ 0- no movement 1- minimal movement, 2, full movement gravity-eliminated, 3- full movement against gravity, 4- full movement but not full resistance, 5- full resistance ], tongue click was rated [ 0-absent, 1-minimal, 2-more than minimal, 3- moderate, 4-hard click, 5-maximal click ], Presence of gag reflex were assessed. ALS Functional Rating Scale –Revised was completed at 3 month intervals in 48 patients [14 bulbar onset; 34 limb onset].
Median ALS FRS-R Bulbar subscore declines 4.5[-5.8 to -1.3 (95% CI)] units in bulbar onset patients and 0.5[-2.1 to 0.0]units in limb onset patients over 12 months[p=0.007]. Tongue click which is actually higher in limb onset patients declines faster by 1.5[-2.0 to – 0.9 (95%CI)]units compared with bulbar onset patients – 0.3[-1.6 to 0.0 (95%CI)]units. Change in tongue click correlated significantly with change in tongue strength[r=0.832; p=0.005]. Change in ALS FRS-R Bulbar subscore correlated significantly with change in platysma strength [r=0.593; p=0.006]. Orofacial muscle strength [face and tongue] but not pharyngeal[palate elevation ]strength changes significantly in ALS patients. Sample size estimates for clinical trials are smaller, but not statistically significantly less in magnitude than changes measured by ALS FRS-R Bulbar subscale item, domain and total score.
The natural history of Facial-Lingual Oro-Motor muscle strength measured clinically correlates with ALS FRS-R Bulbar subscale and other measurements offering a novel set of new clinimetrics to assess new treatment regimens in the bulbar domain.