Shoulder Joint Position Sense (JPS) & Laser-Point assisted Angle Reproduction Test (LP-ART)
Reference:Balke M et al The laser-pointer assisted angle reproduction test for evaluation of proprioceptive shoulder function in patients with instability. Arch Orthop Trauma Surg. 2011 Aug;131(8):1077-84.
The LP-ART requires the patient to memorize various joint positions with eyes open and then with the eyes closed they are asked to reproduce the same joint positions as before.
To evaluate shoulder JPS, a laser pointer (part of the STARmat package www.starmatrehab.com) is taped to the patients distal dorsal forearm / proximal to the wrist.
With the eyes closed, they are requested to slowly raise their arm straight up as far as comfortable and then slowly return back to the original 90� shoulder position as accurately as possible.
When they return, the new position of the laser beam is noted and the patient is asked to open their eyes.
The distance between the new position of the laser beam and the center of the target is measured (estimated).
This JPS test is repeated for shoulder extension, horizontal abduction and horizontal adduction.
What is “Normal”?
Inside the center red target (0-4cm error) is considered excellent
Within the first grey zone (4-8cm error) is considered good
Within the second red zone (8-12cm error) is considered fair / normal
Anywhere outside the second red zone (greater than 12cm error) is considered poorNote: The STARmat is standardized so the patient stands 100cm away from the wall to make the test reliable.For more advanced evaluation & training ask the patient to now close their eyes and move their shoulder towards a specific number on the wall target and return to the center again.
E.g. slowly move your shoulder to 1 o’clock and return back to center. The degree of error can be easily observed during the exercise.
Off by less than 5 is considered excellent
Off by 5-10 is considered good
Off by 10-15 is considered fair
Consistently off by more than 15 is considered poor
In a healthy population, no significant differences in shoulder JPS has been found between dominant and non-dominant shoulders and between men and women.For shoulder JPS home program, no laser beam or STARmat wall target is required.The patient is to simply close their eyes and consciously with full awareness move their shoulder in a clock pattern (12 directions) several times a day.
This exercise should ideally be prescribed to anyone with acute to persistent traumatic shoulder pain (e.g. post fall, dislocation, surgery).
The conscious movements may help minimize the loss of proprioception and potential somatosensory cortex reorganization.