Parkinson’s disease is a common neurodegenerative disorder of the elderly primarily affecting the dopamine producing neurons in substantia nigra region of the brain. The dopamine is a brain neurotransmitter, which helps in the relay of signals from one part of brain to other. The dying dopaminergic neurons cause a motor system dysfunction in the form of imbalance in the muscle control and coordination, which manifests as tremors, rigidity, slowness of movements, dyskinesia, freezing of gait, and frequent falls.
Parkinson’s disease patients, especially in the end stages of the disease, often have a significant amount of muscle atrophy. This muscle wasting or loss of muscle tissue could be due to reduced physical activity because of the symptoms of Parkinson’s disease or if bedridden. Added to the reduced or lack of physical activity, an additional factor to take into account is that Parkinson’s disease is in most cases a disease of old age, a period of life where some amount of normal muscle wasting is to be expected.
Physiotherapy and a home exercise program for Parkinson’s patients do help to prevent this muscle atrophy to a certain extent. Apart from muscle atrophy, some amount of cerebral or brain atrophy is also to be expected in people suffering from Parkinson’s disease, which is in excess to that found in normal people, taking into account the age of the patient in both circumstances.
Differentiation of multiple system atrophy from Parkinson’s disease
The neurodegenerative change in the brain also leads to multiple system atrophy, which is characterized by the shrinkage of the brain cells in the affected areas. These changes can also be visualised on the MRI scans. Multiple system atrophy is often mistaken for Parkinson’s disease and the differential diagnosis between the two of them is quite difficult due to the presence of the overlapping signs and symptoms common to both conditions. Following symptoms are seen in patients of multiple system atrophy.
- Slowing and stiffness of movements
- Inability to balance without support
- Slurred speech
- Difficulty in writing
- Bladder problems like urinary retention, increased frequency of micturition, incontinence, nocturnal enuresis.
- Erectile dysfunction
- Swallowing problems and difficulty in chewing
- Sleep disorders, insomnia, narcolepsy
- Cognitive problems, difficulty with multitasking.
Multiple system atrophy can be distinguished from Parkinson’s disease symptomatically in some ways as in some MSA patients the Parkinson like symptoms manifest only on one side of the body while true Parkinson’s disease is a bilateral condition. Also the characteristic tremor of the hand known as “pill – rolling” tremor seen in Parkinson’s disease does not occur in MSA patients.
Signs and Symptoms of Atrophy in Parkinson’s Disease
The muscles of the body may look small and show decrease in bulk. There will be loss of tone and weakness in the muscles. There may be difficulty in standing and walking when the leg muscles are involved or generalized weakness of the body may be present. Muscle twitching or spasms, often painful, may occur especially in the legs.
Brain atrophy in Parkinson’s disease correlates with cognitive decline. Dementia and decreased cerebral function may occur as a result of cerebral atrophy, where the brain cells and tissues gradually decrease and cause the brain to shrink, and the cumulative incidence ranges to about 70%. There may be associated problems with speech and vision too. The degeneration seen in Parkinson’s disease is not limited to the nigrostriatal dopaminergic system but also involves various regions of the cerebral cortex. The atrophy not only occurs in the hippocampus region, but also bilaterally in the surrounding medial temporal lobe, both of them are known for memory formation and storage.
Diagnosis of Atrophy in Parkinson’s Disease
The test subjects undergo detailed physical, neurological, neuropsychiatric examination, including the clinical history and a standard blood screening along with the thyroid function test evaluation, B12 and folic acid levels, and syphilis serology to rule out other neurological degenerations.
CT scan or MRI can help in diagnosis, both for muscle as well cerebral atrophy.
Treatment of Atrophy in Parkinson’s Disease
Since the main cause of muscle atrophy in Parkinson’s disease is restricted movement and reduced physical activity, these issues have to be addressed aggressively for prevention as well for the treatment of atrophy. Because of their symptoms of rigidity or lack of muscle co-ordination, people with Parkinson’s disease tend to avoid physical activities.
They have to be motivated to do simple aerobic exercises such as walking, cycling or swimming if their condition permits. Aquatic exercises which are performed in a warm pool help to improve muscle tone. Exercises to involve full range of movement of the body, especially the arms and legs, should be encouraged. Yoga and Tai chi exercises help to improve muscle tone and improve strength in the muscles.
For the bedridden patients or in those who cannot undertake these forms of exercise, a physiotherapist could help with other forms of passive exercises and limb movements. One such exercise is movement strategy training. Strategies involving the physical or attentional cues, help to overcome some of the deficits in the balance and coordination created due to the dopaminergic loss. Facilitated exercise programs including the biomechanics, posture training, trunk rotation and normal rhythmic symmetric movements benefits the patients. The exercise must be carried out 4 to 5 times a week for at least 30 to 40 minutes per session. A cool down period is important after the exercise, it allows the muscles to cool down gradually so that they do not become stiff. A cool down period consists of the same exercise activity, but at a progressively slower pace, allowing the muscles to go through a slow yet a full range of motion. Many patients find benefit with massage therapy although this is not as effective as rehabilitation physiotherapy treatments.
In addition, good nutrition is very important in improving muscle bulk and reversing or preventing some amount of muscle atrophy. A reduced protein intake will speed up the loss of muscle bulk and in Parkinson’s patient with a poor diet, this will exacerbate the problem of muscle atrophy.
Adequate treatment of Parkinson’s disease itself as well as certain drug treatment may be of some help to relieve symptoms of cerebral atrophy. However stopping this form of atrophy with conservative measures is unlikely.