Motor Imagery Performance and Tactile Spatial Acuity: Are They Altered in People with Frozen Shoulder?

Area of Science:

• Neuroscience
• Pain Management
• Rehabilitation Science

Background:

• Frozen shoulder (adhesive capsulitis) causes severe chronic pain with poorly understood mechanisms.
• Deficits in motor imagery and tactile acuity are observed in other chronic pain conditions, linked to neuroplastic changes.

Purpose of the Study:

• To investigate alterations in motor imagery performance and tactile acuity in individuals with unilateral frozen shoulder.
• To explore potential neuroplastic changes associated with frozen shoulder pain.

Main Methods:

• A cross-sectional study involving 18 adults diagnosed with frozen shoulder.
• Assessed motor imagery using a left/right judgment task (response time and accuracy).
• Measured tactile acuity via a force-standardized two-point discrimination test on both affected and healthy shoulders.

Main Results:

• Significantly slower response times in the left/right judgment task for the affected shoulder compared to the healthy shoulder (p=0.031).
• Significantly larger two-point discrimination thresholds on the affected shoulder, indicating reduced tactile acuity (p<0.001).
• No significant differences in accuracy for the judgment task or correlations between performance and pain/disability scores or symptom duration.

Conclusions:

• Altered sensorimotor processing and disrupted sensorimotor cortex representations are potential explanations for findings in frozen shoulder.
• These results support the development of treatments targeting neuroplasticity to alleviate chronic shoulder pain.