[Some reflections on the pathophysiology of abnormal movements]

The field of abnormal movements is an area that is in continual expansion within Neurology and treatment is currently available for many of them, at least as far as the symptoms are concerned. Yet, the exact mechanisms of operation of the neurological structures involved in movement are not fully understood.

It seems clear that the basal ganglia play an important role, fundamentally in pseudo-automatic movements, but because they are interconnected with many other structures it is difficult to gain a precise understanding of their individual functions. There are theories based solely on anatomical data, which are not enough to account for everything. The theory of the existence of neuronal circuits seems to explain a wider part of movement, although it still has a number of shortcomings. Another theory of movement disorders is that based on neurochemistry, according to which the imbalance of certain neurotransmitters would be the causation of the disease, but this theory does not enable us to explain all the pathologies related to movement either. A number of clinical observations and the use of animal models, however, have made it possible to draw up pathophysiological hypotheses about the generation of some abnormal movements.

All these approaches have enabled researchers to find symptomatic treatments for certain diseases, but our knowledge of the pathophysiology involved is still far from complete and the chances of enhancing the therapeutic capacity available in such cases in the future are therefore immense.