# The Effect of L-dopa on Postural Stability in Parkinson's Disease Patients
## 2 Materials and Methods  
The study group comprised 13 patients who belonged to the Kielce, Poland Parkinson Disease Association. There were 8 females (61.538%) and 5 males (38.462%). The study took place in November 2013, in the Posturology Laboratory at the Institute of Physiotherapy by the Faculty of Medicine and Medical Sciences, Jan Kochanowski University in Kielce. The examined patients suffered from advanced, idiopathic Parkinson's disease. They still responded well to L-dopa. The duration of the disease was more than 5 years. The daily dose of L-dopa stayed in between the range of 600-1000 mg/d. The patients were subjected to postural stability examination before the morning dose of the drug, and again, 1 h after taking 200 mg of L-dopa (Madopar 250 cap). All procedures performed in the case of studies with human participants took place in accordance with the ethical standards approved by the institutional and/or committee for national research as well as the Declaration of Helsinki from 1964, along with later amendments or analogous ethical standards. The patients were given information regarding the study aim. All of the patients expressed written consent to be participants in this study. The study was conducted in a non-invasive manner and was free of charge. The patients willingly took part in the experiment, perceiving it as a concern for their health. The Unified Parkinson's Disease Rating Scale, that is, the UPDRS motor test, was performed before testing on the Biodex Balance System Platform. Postural stability was assessed with the use of the Biodex Balance System platform. Postural Stability Testing was performed with open eyes and with both of the patient's feet positioned on a stable surface. The platform was blocked, meaning that it was fully stable. After entering the patient's personal information and body height, their position was determined. For this reason, points of reference were considered to be the platform axes as well as the centre line of the foot. In order to determine the position, the angles of the feet positioning via the centre line (right and left foot separately) were entered into the system and displayed on the screen. The Postural Stability Test comprised 3, 20-s trials which were divided by a 10-s interval. During the examination, the patient focused his/her eyesight on a monitor, where a characteristic dot (_COP--Centre of Pressure_) appeared. The patient was instructed to shift body balance in such a manner that the dot (COP) maintain in the middle of the circle appeared on the screen, which was at the point where the coordinate axes intersected. At the time of examination, it was allowed to verbally correct the patient allowed. All of the parameters registered by the posturological platform were collected in an absolutely non-invasive manner; the device could be safely applied in the case of the whole group. Overall Stability Index (\({}^{\circ}\)) reflects variability of platform positioning with regarding to the horizontal plane. This is expressed in degrees and for all movements performed during the test. Its high value is evidence of the great number of movements performed at the time of the test. The Anterior-Posterior Stability Index (\({}^{\circ}\)) mirrors platform displacement variable in the case of sagittal plane movements, which again, are expressed in degrees. Medial-Lateral Stability Index (\({}^{\circ}\)) regards platform displacement variability concerning frontal plane movements in degrees. The score achieved by the patient in the Postural Stability Test depended on the how many times the patient swayed from the center, meaning that postural stability is better when the result is lower. The percentage of time in zone (%)--index regarding the time a patient spent in a given zone. Target zones A, B, C and D are the same, with respect to the platform tilt degree.