Assessing the Difficulties of Walking in PARKINSON’S DISEASE
Changes in the way they walk are an early alert that people may be developing some of the symptoms of PARKINSON’S DISEASE. Walking with smaller steps and kind of shuffling along without the rhythm of normal arm swing is a tell tale sign of PARKINSON’S DISEASE. But when does it start and how does it develop? Does dopamine replacement therapy help? Why do some people progress faster than others? Can early detection help slow the progression and help maintain quality of life a little longer? A group of researchers at Newcastle University in the United Kingdom focused on these issues and reported their findings in the journal, Movement Disorders.
Most studies on gait impairment (walking difficulties) have been done on subjects with more advanced disease symptoms and who have been on dopamine replacement therapies, so there has not been much knowledge about the early stages and progression of gait problems. Gait disturbances can be divided into 16 different characteristics, some of which are greatly helped by dopamine replacement therapies and others remain resistant. The researchers set out to establish an understanding of how gait disturbances progress in early PD, which characteristics responded to or were resistant to dopamine and to find if these responses might be useful in helping to make earlier diagnosis and treatments to delay the progression.
One hundred twenty one people newly diagnosed with PD and 184 non-Parkinson controls were recruited. All the participants were tested over the course of 18 months in comprehensive gait studies divided into 5 domains that included pace, variability, rhythm, asymmetry and postural control. Each of these domains were further divided into categories such as step velocity, step length, swing time, stance time and postural control. The PARKINSON’S subjects demonstrated significant impairment in 12 of the 16 characteristics of gait compared to the controls. Based on their symptoms the PD subjects were classified as either Postural Instability Gait Disturbance (PIGD) or Tremor Dominant (TD) with the PGID group showing the most impairment initially but showing minimal progression over the 18 month period while the TD group demonstrated slightly more progression in both step length and swing rhythm.
While gait characteristics such as length of step and swing time did demonstrate a decline over 18 months, PD subjects evaluated on their normal daily dopamine replacement therapy showed improvement, which continued to improve as the daily dopamine dose increased over the 18 month study. Impairment in width of step, particularly in the PGID group indicated problems with balance and postural control. These symptoms were not improved on dopamine replacement therapy.
These results demonstrate the need for early evaluation of gait characteristics to identify both dopamine responsive and dopamine resistant traits in order to initiate therapies that will improve walking and reduce falls from lack of balance. The failure of some characteristics of gait to respond to dopamine replacement therapy indicates a more complex involvement between dopamine and other neurological pathways.
Authors of this study include first author Brook Galna, Ph.D., Sue Lord, Ph.D., David J. Burn, M.D. and Lynn Rochester, Ph.D. all of whom are affiliated with The Newcastle University Institute for Ageing and the Institute of Neuroscience at Newcastle University, Newcastle Upon Tyne, in the United Kingdom.
Galna, B., Lord, S., Burn, D.J., Rochester, L.’ Progression of Gait Dysfunction in Incident Parkinson’s Disease:Impact of Medication and Phenotype. Published online 00 Month 2014 Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/mds.26110
Review by Marcia McCall