Postural instability in Parkinson's disease: a comparison with and without a concurrent task.

Area of Science:

• Neuroscience
• Gerontology
• Rehabilitation Science

Background:

• Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder affecting motor control, often leading to postural instability and increased fall risk.
• Attentional mechanisms play a crucial role in maintaining balance, particularly in individuals with neurological conditions.
• Understanding how dual tasking affects balance in PD is vital for developing effective fall prevention strategies.

Purpose of the Study:

• To investigate the impact of dual task performance on postural instability in individuals with idiopathic Parkinson's disease (PD) compared to healthy elderly controls.
• To assess the extent of balance disturbance by diverting attention to a secondary cognitive task, minimizing compensatory attentional mechanisms.

Main Methods:

• A study involving 45 participants: 15 with PD and a history of falls, 15 with PD and no history of falls, and 15 age- and sex-matched healthy controls.
• Participants performed balance tasks under single-task (steady standing, self-initiated perturbations, external perturbation) and dual-task conditions (concurrent verbal-cognitive task).
• Balance was assessed during steady standing (various stances), self-initiated movements (arm raise, step tests), and external perturbation (shoulder tug test).

Main Results:

• Dual tasking significantly impaired performance on the arm raise test for all groups, the step test for PD fallers and controls, and tandem stance for PD fallers.
• The shoulder tug test revealed significant differences between the three groups in both single-task and dual-task conditions, with similar deterioration rates.
• PD fallers exhibited more severe initial balance deficits, and dual tasking exacerbated these deficits, placing them at higher risk of losing equilibrium.

Conclusions:

• Dual tasking significantly exacerbates postural instability in individuals with Parkinson's disease, particularly those with a history of falls.
• The findings underscore the critical role of attention in maintaining balance for PD patients and suggest that dual tasking reveals underlying balance impairments.
• These results have implications for fall risk assessment and the design of rehabilitation programs aimed at improving balance and reducing falls in PD.