How will you detect a syndrome of Parkinson's disease early?
By" Dr. Shafli Sabahranjak Published on: NORTHWEST PARKINSON'S FOUNDATION website
Parkinson's disease was first described about a hundred years ago, but proved difficult to control in terms of curative treatments. The basic medical approach is to identify the disease in its early stages and try to slow down its continuous rate of progress. Tremors, loss of muscle control and limb stiffness are the main symptoms of Parkinson's disease.
The paradox is that when the symptoms develop and the confirmation of the diagnosis based on these symptoms arrives, the patient's motor skills are already impaired. Loss of motor control leads to a loss of independent functioning and has a real impact on the quality of life. Therefore, the search for early symptoms of Parkinson's disease that precede a state of loss of motor control is an important topic in neurological research now.
A long-term study known as the Honolulu-Asia Study on Aging (HAAS) has helped shed light on the development of early symptoms of Parkinson's disease. In this study, 8006 Japanese Americans were examined periodically for 40 years. From 1991, cases of Parkinson's disease began to appear in this group. The diagnosis was made according to the independent diagnosis of two neurologists. Post-mortem autopsies were also performed on the brains of those who died in this group, in order to confirm the existence of Lewy bodies - an intracellular characteristic of Parkinson's disease. The study helped identify several behavioral trends in patients that preceded the motor symptoms of Parkinson's disease. Increased sleep times during the day, loss of the sense of smell emerged as the two typical symptoms in patients who subsequently developed Parkinson's disease. Constipation was also identified as a phenomenon that increased the risk of Parkinson's disease in this group of patients.
Patients who developed Parkinson's disease showed relatively slow responses to a computer response test. In addition to the clinical diagnosis of Parkinson's disease, postmortem analysis of the brains of the people who showed the slowest responses showed the development of random Lewy bodies. Since tests such as reaction time to a certain cognitive challenge can be quantified, it may be possible to identify threshold values in the reaction times and separate high-risk patients from low-risk patients. Despite this, in this study no analysis of the results was conducted in order to identify a quantitative threshold level. All these abnormal behaviors were observed 7-8 years before the death of the patients, which is enough time for therapeutic intervention. The morbidity rate in Parkinson's disease was significantly greater when symptoms such as constipation (less than one bowel movement per day) and slow response time to a computerized test were seen together. Hemoglobin levels in the blood can become a preliminary sign for the detection of Parkinson's disease. In a normal state, the hemoglobin level decreases with age, but in the above study, individuals with levels equal to or higher than 16 mg/100 ml of hemoglobin at the age of 71-75 were more likely to develop Parkinson's disease when they were tested again at the age of 80. An increase in the level of iron in the blood was known to be associated with the disease Parkinson's.
Are these symptoms absolute? These symptoms are certainly not absolute and are not as black and white as diagnostic tests that test certain levels of biochemical markers of disease. Nevertheless, these signs and symptoms are of enormous predictive value, given that they are seen 7-8 years before the onset of motor symptoms and can be recognized as progression of Parkinson's disease. In addition, verification that the patients who showed these symptoms were indeed patients with Parkinson's disease was the finding of Lewy bodies in the sections made in their brains after their death, which is a sure sign of the existence of Parkinson's disease.
The researchers concluded that the combined appearance of these symptoms - loss of the sense of smell, constipation, longer reaction time, high hemoglobin levels and longer sleep time during the day - increases the risk of developing Parkinson's disease as a result.
Even if these symptoms are only suggestive and not definitive in their determination of Parkinson's disease, they can raise warning bells for doctors about the possibility of the onset of Parkinson's disease in older patients and allow a window of time for therapeutic intervention before movement control is lost.
bibliography
Ross GW, Abbott RD, Petrovitch H, Tanner CM, & White LR (2012). Pre-motor features of Parkinson's disease: the Honolulu-Asia Aging Study experience. Parkinsonism & related disorders, 18 Suppl 1 PMID: 22166434
Abbott RD, Ross GW, Tanner CM, Andersen JK, Masaki KH, Rodriguez BL, White LR, & Petrovitch H (2012). Late-life hemoglobin and the incidence of Parkinson's disease. Neurobiology of aging, 33 (5), 914-20 PMID: 20709430
