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RehabMeasures Instrument

Functional Axial Rotation

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Purpose

Measures a composite of available rotational motion (cervical, thoracic and lumbar). Measurements include physical rotation (FAR-p) and the visual angle of acuity (FAR-v) obtained while looking behind oneself. The ability to rotate in order to look posteriorly supports functions such as those required to rotate and view left or right posteriorly while driving.

Link to Instrument

Acronym FAR includes 2 subdivisions: FAR-p = Functional Axial Rotation (physical motion) & FAR-v = Functional Axial Rotation (visual acuity angle)

Area of Assessment

Range of Motion

Assessment Type

Performance Measure

Administration Mode

Paper & Pencil

Cost

Free

Diagnosis/Conditions

  • Pain Management
  • Parkinson's Disease & Movement Disorders

Key Descriptions

  • To complete the measurement, subjects are seated inside of a 1-meter diameter circular measuring hoop with their pelvis stabilized.
  • The measuring hoop is positioned at eye level and has object symbols at 5-degree intervals on the interior of the hoop. Patient wears a device that provides a central head pointer (could be C-ROM unit or other).
  • Subject performs full active trunk and neck rotation to the right and to the left. At the end of rotation, subject identifies the furthest object visible on the hoop. The object must be identified accurately – if not, subject would identify the next object until accurate angle of visual acuity is established.
  • Standardization:
    1) Pelvis stabilized on seat with 2 straps
    2) Measuring hoop at eye level of subject
    3) 90 and 270 degree angle markers are positioned to align with subject’s left and right greater trochanter (frontal plane)
    4) Subject actively turns as far as possible in each direction with arms hanging freely
    5) Subject performs 1 practice trial and 2 test trials in each direction
  • Scale: 5 degree intervals marked on the hoop.
  • Scoring:
    1) Record the maximum angle of rotation based on the pointer
    2) Record the maximum angle of visual acuity based on object identification

Equipment Required

  • Measuring hoop of one meter diameter with object symbols or random numbers located at 5 degree intervals on the interior of the hoop
  • Supportive stands to hold hoop horizontally at eye level of subject (original source used 2 tripod stands)
  • Head pointer

Time to Administer

5-10 minutes

Required Training

Reading an Article/Manual

Age Ranges

Adult

18 - 64

years

Elderly Adult

65 +

years

Instrument Reviewers

Erin Hussey, DPT, MS, NCS & the PD EDGE Task Force of the Neurology Section of the APTA

Body Part

Neck
Back

ICF Domain

Body Structure
Body Function

Measurement Domain

Motor

Professional Association Recommendation

Recommendations for use of the instrument from the Neurology Section of the American Physical Therapy Association’s Multiple Sclerosis Taskforce (MSEDGE), Parkinson’s Taskforce (PD EDGE), Spinal Cord Injury Taskforce (PD EDGE), Stroke Taskforce (StrokEDGE), Traumatic Brain Injury Taskforce (TBI EDGE), and Vestibular Taskforce (Vestibular EDGE) are listed below. These recommendations were developed by a panel of research and clinical experts using a modified Delphi process.

For detailed information about how recommendations were made, please visit:  

Abbreviations:

 

HR

Highly Recommend

R

Recommend

LS / UR

Reasonable to use, but limited study in target group  / Unable to Recommend

NR

Not Recommended


Recommendations Based on Parkinson Disease Hoehn and Yahr stage:

 

I

II

III

IV

V

PD EDGE

LS/UR

LS/UR

LS/UR

LS/UR

NR

 

Recommendations for entry-level physical therapy education and use in research:

 

Students should learn to administer this tool? (Y/N)

Students should be exposed to tool? (Y/N)

Appropriate for use in intervention research studies? (Y/N)

Is additional research warranted for this tool (Y/N)

PD EDGE

No

No

No

Not reported

Considerations

  • Inconsistent in published literature. Some specify 2 items, some indicate one (left / right) FAR measure without specifying as FAR-p or FAR-v. 
    • Two: Trunk rotation: performed left and right 
      • FAR-p: Left Rotation and Right Rotation 
      • FAR-v: Visual acuity with left and with rotation 
  • Interpreting compared to published data: Total FAR documented in studies has been used in many different ways (eg, to mean the average of 2 trials in each direction; only using the least mobile direction; summation of both left and right rotation), thus reducing any capability for comparison. Tool appears to be in evolution, with 2 elements reported initially (FAR-p and FAR-v) but only 1 subsequently (FAR) in a way that appears to represent FAR = FAR-p.

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Parkinson's Disease

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Normative Data

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

Test/Retest Reliability

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

Interrater/Intrarater Reliability

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)

Criterion Validity (Predictive/Concurrent)

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.

Construct Validity

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.

Bibliography

Schenkman, M., Cutson, T. M., et al. (1997). "Reliability of impairment and physical performance measures for persons with Parkinson's disease." Phys Ther 77(1): 19-27. 

Schenkman, M., Ellis, T., et al. (2011). "Profile of functional limitations and task performance among people with early- and middle-stage Parkinson disease." Phys Ther 91(9): 1339-1354. 

Schenkman, M., Hughes, M. A., et al. (1995). "A clinical tool for measuring functional axial rotation." Phys Ther 75(2): 151-156. 

Schenkman, M., Morey, M., et al. (2000). "Spinal flexibility and balance control among community-dwelling adults with and without Parkinson's disease." J Gerontol A Biol Sci Med Sci 55(8): M441-445.   

Schenkman, M. L., Clark, K., et al. (2001). "Spinal movement and performance of a standing reach task in participants with and without Parkinson disease." Phys Ther 81(8): 1400-1411.