Symptoms and side effects in the course of Parkinson's disease.

From our investigations, we are tempted to assume that all types of akinesia, including "freezing", off-phases, Yo-Yoing and akinetic crises, are primarily symptoms of PD, while hyperkinesia, stretch spasms and pharmacotoxic psychosis are "side-effects". Therefore side-effects can be triggered by antiparkinsonian therapy while they will disappear after withdrawal of the drugs inducing them. Antiparkinson drugs alleviate major symptoms like akinesia and rigidity but sometimes and especially as reflection of advanced parkinsonism, might amplify minor symptoms (freezing, off-phases, Yo-Yoing), which then predominantly at high drug doses occur earlier and more intensively. Therefore, minor symptoms can be observed more frequently in the advanced stages of PD. Depressed phases belong to the symptom complex as is bradyphrenia and dizziness. Bradyphrenia is the psychic correlate to akinesia. Dementia, if at all is a symptom, but more likely this disease occurs occasionally in combination with parkinsonism.