Functional Axial Rotation

Parkinson’s Disease:(Schenkman et al, 2011; Cross sectional data from 5 studies with n = 339; mean age = 66.1 (9.34); MMSE > 23/30; Mean years duration of PD diagnosis = 6.0 (5.12); Hoehn and Yahr stages 1-3. HY 1: n = 10, HY 2: n = 138, HY 2.5: n = 104, HY 3: n = 83. Normative data based on previously unpublished data representing ages 40-59: 22 men and 18 women.) 

• Male Mean 117 (14.2) deg: Female mean 127.8 (10.4) deg (not specified in article but this is presumed to represent FAR-p, not FAR-v) 

(Schenkman et al, 2000; n = 251; 56 with PD; 195 without PD or other disorder) 

Measured total FAR as the sum of left + right rotation 

• Total FAR, excursion (from farthest angle of right rotation to the farthest angle of left rotation), was > 300 degree for a sample of 20- to 40-year-old subjects and < 220 degrees for a sample of 76-year-old adults. not specified in article but this is presumed to represent FAR-p, not FAR-v) 
• FAR (degrees) PD group 180.3 (30.0) non-PD group 208.7 (26.4) p = 0.0000

Parkinson’s Disease: (Schenkman et al, 1995; n = 17 without neurologic disorder or known rotational limitation; Mean age 48.8 (21.6); completed 1 practice and 2 test rotations left and right.) 

Test-retest at 5-10 day interval. 

• FAR-p: Excellent test-retest reliability (ICC = 0.95) 
• FAR-v: Excellent test-retest reliability (ICC = 0.90) 

(Schenkman et al, 1997; n = 15 (13 male, 2 female) with PD. H&Y stages 2 (n = 1), 2.5 (n = 8) and 3 (n = 7). Mean years since PD diagnosis = 6.2. Mean age 74.5 (5.7). MMSE of > 22/30.) 

Test-retest performed at 1-week interval. 

• Excellent test-retest reliability (ICC = 0.89; lower CI = 0.81) 

(Schenkman et al 2001; N = 48; 16 with PD, mean age 67.2 (7.3); modified Hoehn & Yahr stages 1.5–3 (1 = 1.5, 2 = 2, 7 = 2.5, 6 = 3); 32 without PD mean age 66.3 (8.9), matched for sex and BMI; those with PD tested during “on” medication state if experiencing “on”/ “off” fluctuations) 

Mean FAR calculated as average of left and right physical rotation. 

• Excellent reliability in PD subjects: ICC = 0.89 
• Excellent reliability both groups: ICC = 0.90 and 0.95, left and right rotation, respectively

Parkinson’s Disease:

(Schenkman et al, 1995)

• FAR-p: Excellent interrater reliability (ICC = 0.97). 

(Schenkman et al, 2001; Interrater reliability assessed for 17 control subjects: mean age = 48.8 (21.6)) 

• Excellent interrater reliability (ICC = 0.97)

Parkinson’s Disease:

(Schenkman et al, 2001) 

• Using regression model analysis, 36% of variance in forward reaching was explained by a combination of lateral trunk flexion (25%) and total axial rotation measures (10%), with total rotation accounting for as much as 3 cm (1.2 inches) of the total reach.

Parkinson’s Disease:

(Schenkman et al, 1997) 

• Adequate-Excellent correlation with physical performance measures that incorporate motion of the neck and back (canonical correlation coefficient r = 0.60, p = 0.005) 

(Schenkman et al, 2001) 

Discrimination PD vs non-PD: 

• FAR with mean difference = 10 degrees less in PD vs control group (p < 0.005) 

(Schenkman et al, 2011) 

• FAR and HY stages: n = 252; Linear trend of decline across HY from stages 1 to 3 of approx 20 degrees: F value = 23.43 (p < 0.0001); Cohen F = 0.09 
• FAR and UPDRS motor score: n = 249; Linear trend of decline across UPDRS motor scores with 36 degree reduction in total axial rotation between those with highest to lowest UPDRS scores; F value = 32.63 (p < 0.0001); Cohen F = 0.13 
• FAR has potential to detect early loss of rotation – noted those with PD HY stages 1-2 or lower UPDRS scores already showed significantly less FAR compared to the normative adult values used for comparison.