DOES SHOULDER PROPRIOCEPTION CHANGE IN THE PRESENCE OF PAIN? AN EXPLORATION OF SHOULDER PROPRIOCEPTION OUTCOME MEASURES AND CLINICAL IMPLICATIONS

A.L. Ager¹, J.-S. Roy², M.-O. Dubé², D. Borms¹, A.M. Cools¹

¹Ghent University, Department of Rehabilitation Sciences, Ghent, Belgium, ²Laval University; Center for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Department of Rehabilitation, Quebec, Canada

Background: Individuals affected by rotator cuff-related shoulder pain (RCRSP) are said to have altered shoulder proprioception. However, the relationship between shoulder pain and proprioception is not well established. This knowledge is important because shoulder proprioception rehabilitation is often included in treatment plans for RCRSP without adequate evidence that it relates to pain.

Purpose: To investigate the relationship between shoulder pain and proprioception.

Methods: With ethical approval and informed consent, 44 participants were recruited to a cross-sectional comparative study, twenty-two with RCRSP and 22 matched pain-free participants (mean [X̅] age (± standard deviation) 27.6 years (±4.8) and 23.4 years (±2.5)). Participants performed two active joint re-position tests in a single session, using a) the Shoulder Proprioception Reaching Test (SPReT) (reaching towards 7 targets in a star shape, on a wall-mounted adjustable poster) (intra-session ICC=0.77; inter-rater ICC=0.86) (Ager et al. submitted); and b) at 90% of maximum internal rotation (IR) using the Biodex System^TM(intra-session ICC = 0.92 0.07) (Ager et al. 2017). Participants had three memorization trials followed by three reproduction trials while blindfolded. Proprioception errors (PEs), the difference between the memorized and reproduced trials, were recorded in centimetres (SPReT) and degrees (Biodex). Pain levels were captured pre- and post-evaluation using a verbal 11-point Likert Numerical Pain Rating Scale. Relationships between PE and pain for each outcome, within each group and between groups, were investigated using independent t-tests and Spearman rank correlation analyses.

Results: The pain-free participants did not report pain during testing, nor did the RCRSP participants with the SPReT. However, 86.4% reported pain after the evaluation with the Biodex (X̅ pain levels: 4.1 points), reflecting a clinically important increase of 2.28 points. No significant differences in PE between groups were found with the Biodex (P = 0.32). A weak correlation (r range = -0.26 to 0.38) was found between pain and PE with the SPReT and a weak to moderate correlation between pain and PE with the Biodex (r = 0.39 to 0.53). The RCRSP participants demonstrated marginally lower PE with the SPReT, with the overall mean PE and targets in elevation compared to pain-free participants (overall X̅ = 4.6 ± 1.2cm vs 5.5 ± 1.5cm; Superior [S] 3.8 ± 2.1cm vs 5.7 ± 2.9cm; Superior-Lateral non-dominant [SLND] 4.3 ± 2.2cm vs 6.1 ± 2.8cm). Significant correlations between pain and PE with the SPReT were found with elevated targets ([S] target (r= -0.33, P = 0.02) and [SLND] target (r = -0.37, P = 0.01); where individuals with higher levels of baseline pain demonstrated better proprioception acuity (lower PEs).

Conclusions: Individuals affected by RCRSP demonstrated less PEs in elevation with the SPReT, suggesting a possible change to interoception, the sensory reweighting of proprioception feedback in the presence of pain. This study contributes to the conversation on sensory reweighting and potential changes to proprioception in the presence of pain.

Implications: Rehabilitation of proprioception in the presence of pain requires greater understanding before determining the therapeutic value in a clinic.

Funding acknowledgements: Funding was provided by the Faculty Mobility Fund (2019) from Ghent University, Belgium.

Keywords:
Proprioception
Interoception
Rehabilitation

Topics:
Musculoskeletal: upper limb
Disability & rehabilitation
Pain & pain management

Did this work require ethics approval? Yes

Institution: Ghent University, CIRRIS & Laval University

Committee: Ethical Committee Ghent University / Research Ethics Committee of CIUSSS-CN

Ethics number: Belgium: B670201836235 and Canada: # 2019-1762