Many Parkinson’s disease patients are able to ride a bicycle and have improved their motor performance and gait ability. This study will throw light on various aspects of Parkinson’s disease and how bicycling improves the motor functioning in Parkinson’s disease patients. At last this article has also including various studies that supports the purpose of bicycling in case of Parkinson’s disease.
Parkinson’s disease is considered one of the most common degenerative diseases of the nervous system that affects movement.
Primary manifestations of Parkinson’s disease are tremors, slowness of movement, stiffness of the muscles, postural instability, gait disturbances and lack of
Bradykinesia in particular is considered a major cause of motor difficulties, affecting almost all activities of daily living. Since there is no cure for Parkinson’s disease, current pharmacological therapies can only mitigate symptoms but do not have disease-modifying effects. Moreover as Parkinson’s disease progresses, the therapeutic window for medical therapies narrows with an increased risk of side effects.(3)
Parkinson’s disease is multifactorial disease with both genetic and environmental factors playing a role. Age is the highest risk factor for Parkinson’s disease, with median age of onset being 60 years of age. Environmental factors like cigarette smoking and exposure to pesticides, herbicides and heavy metals have also been associated with causation of Parkinson’s disease. The genes that have been found to potentially cause Parkinson’s disease are assigned a “PARK” name in order they were identified. Mutations in park genes either demonstrate autosomal dominant eg SCNA, LRRK2, VPS32 or autosomal recessive example PRKN, PINK1, DJ1. Numerically most important genetic risk factors predisposing to Parkinson’s disease are mutations in GBA1, a gene encoding beta gucocerebrosidase which is a lysosomal enzyme responsible for hydrolysis of glucocerebrosidase. (4)
Pathogenesis of Parkinson’s disease
Multiple mechanisms have been put forward for Pathogenesis of Parkinson’s disease, alpha synuclein aggregation being central to the development of the disease. The various processes thought to be involved in pathogenesis of Parkinson’s disease are as follows:
Abnormal protein clearance- There are 2 protein clearance system, the ubiquitin-proteosome system and the autophagy lysosome pathway.
Microscopically, the brain in idiopathic Parkinson’s disease is often unremarkable with mild atrophy of frontal cortex and ventricular dilation in some cases. The main distinctive morphological change in the Parkinson’s disease brain is observed in transverse sections of the brain stem, where almost all cases present with loss of darkly pigmented area in the substantia nigra pars compacta and locus ceruleus. The loss of pigmentation signifies loss of dopaminergic neurons in substantia nigra pars compacta and noradrenergic neurons in locus ceruleus. The pathological hallmark of Parkinson’s disease is presence of abnormal cytoplasmic deposits within neuronal cell bodies which are immune reactive for protein alpha synuclein. These pathological protein aggregates are called Lewy bodies and are often accompanied by dystrophic neuritis.(4)
How cycling is boon to Parkinson’s disease patient ?
Understanding that cycling is beneficial to Parkinson’s disease patient is very necessary to make ourselves convinced and actually implement it in lives of Parkinson’s disease patient.
For the motor cortex to enable an ongoing motor process, it relies on the somatosensory input from peripheral sensors like joint receptors, muscle spindles and cutaneous reflexes. As the proprioceptive system has been found to be impaired in Parkinson’s disease patients, this results in lack of peripheral afferent input and disturbed motor output. It is hypothesized that a lower amount of intrinsic information processed by the brain during cycling may result in less disruption of cortico basal ganglia circuitry, reducing the pathological beta band synchronisation observed in Parkinson’s disease patients. Intrinsic information in this case includes information from balance sensors and postural control in conjunction with muscle and tendon control. Therefore one of the explanations for preserved cycling ability can be found in the continuos nature of cycling and general absence of continuos stationary phases during walking. Therefore, lower amount of information processed by the brain during cycling could reduce the risk of obstructed signal between the cortico-basal loops and thus reduce the freezing of gait. In the same way, freezing of gait was found to be partially alleviated by using a “ walk bicycle”, also known as bicycle without pedals and with a low seat. As even though the locomotion on the walk bicycle requires alternating stepping movements of legs, it seems to reduce the need for postural control and lateral weight shifts that were shown to be abnormally coupled in patients with FOG( freezing of gait). (3)
Evidence based medicine
Today’s world demands evidence for everything so even for our blog article we have evidence to support our verdict that cycling does playrole in preventing and/or improving symptoms of Parkinson’s disease patients. Following are research articles that support the same.
Study titled “ Effects of low-resistance, interval bicycling intervention in Parkinson’s disease, says that low resistance recumbent cycling is useful training modality to improve disease severity, functional mobility, balance, cognitive and upper extremity function in people with mild to moderate PD.(1)
Study titled “Exercise elevates dopamine D2 receptor in a mouse model of Parkinson’s disease: in Vivo imaging with [18^F]Fallypride, proves that high intensity treadmill exercise led to an increase in striatal DA-D2R specific ligand fallypride, we led to an increase in striatal DA-D2R expression that was most pronounced in MPTP compared to saline treated mice. Exercise induced changes in the DA-D2R in the dopamine depleted basal ganglia are consistent with the potential role of this receptor in modulating medium spiny neurons function using western immunoblotting analysis of synaptoneurosomes ( MPTP - 1 methyl 1-4-phenyl-1,2,3,6-tetrahydropyridine). (2)
Mehmet Uygur, PhD, Maria Bellumori, PhD, and Christopher A. Knight, PhD. Effects of low-resistance, interval bicycling intervention in Parkinson’s Disease. Pubmed central
Marta G. Vuckovic, MSc, Quanzheng li, PhD, Beth Fisher, PT, PhD, Angelo Nacca, PhD, Richard M Leahy, PhD, John P. Walsh, PhD, Jogesh Mukherjee, PhD, Celia Williams, BSc, Michael W. Jakowec, PhD, and Giselle M Petzinger, MD. Exercise elevates Dopamine D2 receptor in a mouse model of Parkinson’s disease: In vivo Imaging with [^18F]Fallypride.
Teja Licen, Martin Rakusa, Nicolas I Bohnen, Paola Manganotti, Uros Marusic. Brain dynamics underlying preserved cycling ability in patients with Parkinson’s disease and freezing of gait.
Antonina Kouli, Keli M, Torsney, and Wei-Li Kuan. Parkinson’s disease : Eitiology, Neuropathology and Pathogenesis.
Writer: Dr Dhruv Barai
Editor: Asra Aijaz
Promotor: Dr Meera Shah