A meta-analysis and systematic review of changes in joint position sense and static standing balance in patients with whiplash-associated disorder

Abstract

Objective: To synthesise and analyse the current evidence regarding changes in joint position sense (JPS) and standing balance in people with whiplash-associated disorder (WAD) taking the presence or absence of dizziness into account.

Data sources: PubMed, CINAHL Plus, Web of Science, Embase, MEDLINE and APA PsycINFO were searched by two independent reviewers from inception until August 2020 and reference lists of all included studies were also reviewed.

Study selection: Only cross-sectional studies that measured JPS and/or standing balance between people with WAD vs. healthy controls (HC) or people with WAD complaining of dizziness (WADD) vs. those not complaining of dizziness (WADND) were selected.

Data extraction: Relevant data were extracted using specific checklists and quality assessment was performed using Downs and Black Scale (modified version).

Data synthesis: Twenty-six studies were included. For JPS, data were synthesized for absolute error in the primary plane of movement for separate movement directions. For standing balance, data were synthesized for traditional time- and frequency domain sway parameters considering the conditions of eyes open (EO) and eyes closed (EC) separately. For meta-analysis, reduced JPS was observed in people with WAD compared to HC when the head was repositioned to a neutral head position (NHP) from rotation (standardised mean difference [SMD] = 0.43 [95%: 0.24-0.62]) and extension (0.33 [95%CI: 0.08-0.58]) or when the head was moved toward 50° rotation from a NHP (0.50 [0.05-0.96]). Similarly, people with WADD had reduced JPS compared to people with WADND when the head was repositioned to a NHP from rotation (0.52 [0.22-0.82]). Larger sway velocity and amplitude was found in people with WAD compared to HC for both EO (0.62 [0.37-0.88] and 0.78 [0.56-0.99], respectively) and EC (0.69 [0.46-0.91] and 0.80 [0.58-1.02]) conditions.

Conclusion: The observed changes of JPS and standing balance confirms deficits in sensorimotor control in people with WAD and especially in those with dizziness.

Fig 1. Flowchart of study selection.

Fig 2. Forest plot demonstrating meta-analysis of absolute error (in degrees) of JPS when repositioning the head to neutral-head-position from extension and rotation and when repositioning the head toward targets set at 30° and 50° rotation from neutral-head-position in people with WAD vs. HC.

WAD: whiplash-associated disorder; HC: healthy control; SD: standard deviation; IV: inverse variance; CI: confidence interval; Std: standardized.

Fig 3. Forest plot, without meta-analysis, demonstrating absolute error (in degrees) of JPS when repositioning the head to neutral-head-position from flexion and when repositioning the head toward a target set at 20° side-bending from neutral-head-position in people with WAD vs. HC.

WAD: whiplash-associated disorder; HC: healthy control; SD: standard deviation; IV: inverse variance; CI: confidence interval; Std: standardized.

Fig 4. Forest plot demonstrating meta-analysis of absolute error (in degrees) of JPS when repositioning the head to neutral-head-position from extension and rotation in WAD_D group vs. WAD_ND group.

WAD_D: whiplash-associated disorder presenting with dizziness; WAD_ND: whiplash-associated disorder not presenting with dizziness; SD: standard deviation; IV: inverse variance; CI: confidence interval; Std: standardized.

Fig 5. Forest plot demonstrating meta-analysis of sway velocity and sway amplitude (eyes open) in people with WAD vs. HC.

WAD: whiplash-associated disorder; HC: healthy control; SD: standard deviation; IV: inverse variance; CI: confidence interval; Std: standardized; MVEL: mean velocity (mm/s); PL: path length (mm); AR: area (mm²); PAR: perimeter of sway area (mm); AMP: amplitude (mm); AP: anteroposterior; NSW: narrow stance width.

Fig 6. Forest plot, without meta-analysis, demonstrating sway velocity, sway amplitude and sway energy (eyes open) in people with WAD vs. HC.

WAD: whiplash-associated disorder; HC: healthy control; SD: standard deviation; IV: inverse variance; CI: confidence interval; Std: standardized; VEL: velocity (mm/s); PL: path length (mm); AMP: amplitude (mm); RNG: range (mm); AP: anteroposterior; ML: mediolateral; CSW: comfortable stance width; NSW: narrow stance width.

Fig 7. Forest plot demonstrating meta-analysis of sway velocity and sway amplitude (eyes closed) in people with WAD vs. HC.

WAD: whiplash-associated disorder; HC: healthy control; SD: standard deviation; IV: inverse variance; CI: confidence interval; Std: standardized; MVEL: mean velocity (mm/s); PL: path length (mm); AR: area (mm²); PAR: perimeter of sway area (mm); AMP: amplitude (mm); AP: anteroposterior; NSW: narrow stance width.

Fig 8. Forest plot, without meta-analysis, demonstrating sway velocity, sway amplitude and sway energy (eyes closed) in people with WAD vs. HC.

WAD: whiplash-associated disorder; HC: healthy control; SD: standard deviation; IV: inverse variance; CI: confidence interval; Std: standardized; VEL: mean velocity (mm/s); PL: path length (mm); RNG: range (mm); AMP: amplitude (mm); AP: anteroposterior; ML: mediolateral; CSW: comfortable stance width; NSW: narrow stance width.

Fig 9. Forest plot, without meta-analysis, demonstrating sway energy (eyes closed) in WAD_D vs. WAD_ND groups.

WAD_D: whiplash-associated disorder presenting with dizziness; WAD_ND: whiplash-associated disorder not presenting with dizziness; SD: standard deviation; IV: inverse variance; CI: confidence interval; Std: standardized.