Objective assessment of upper limb tremor distinguishes Parkinson’s fallers and non-fallers and is predictive of future falls
Kerr G[1,2], White N, Morrison S
- Movement Neuroscience, Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
- School of Exercise & Nutrition Sciences, Queensland University of Technology, Brisbane, Australia.
- Department of Physical Therapy, Old Dominion University, Norfolk, Virginian, U.S.A.
Postural instability leading to falls and injury is a disabling feature of Parkinson’s disease (PD). Increased rigidity of the legs and trunk contributes to postural instability. However, the contribution of tremor to postural instability is less certain, even though both resting and postural tremor forms are a common motor problem. Bilateral upper limb postural and resting tremor responses of PD (51) and age-matched controls (39) were assessed while they stood on a force plate. All data were recorded at 100 Hz for 30 s. Clinical falls-risk tests and neurological assessments were also performed. Falls were recorded prospectively over 12 months. Falls occurred in 69% of PD and 46% of older people over 12 months. PD fallers had longer disease duration, greater dopamine agonist use, increased freezing of gait, decreased activities of daily living compared to PD non-fallers. Both postural and resting tremors were greater for PD fallers compared to PD non-fallers, Control fallers and Control non-fallers. There were no differences between Control Faller and Non-Faller groups. Anterior-Posterior postural sway was greater for PD Fallers compared to Control Fallers and Non-Fallers for both postural and resting tremor conditions. Linear discriminant function analysis by forward variable selection revealed that a combination of postural upper limb tremor RMS, dopamine agonist use and Tinetti total score predicted falls outcome in the Parkinson’s group with a sensitivity of 89%, specificity of 69& and accuracy of 82%. Objective assessment of upper limb tremor distinguishes between Parkinson’s fallers and non-fallers and is an important predictor of future