a group of movement disorders that occur when the extrapyramidal system is disrupted – the brain structures that regulate movement control, coordination and posture, including the basal ganglia. The causes can be neurological diseases, such as Parkinson’s disease, or side effects of medications, especially antipsychotic drugs. Symptoms include tremor, rigidity, bradykinesia, dystonia, akathisia, and involuntary movements (tardive dyskinesia). Treatment depends on the cause and may include correction of drug therapy or the prescription of drugs that reduce movement disorders.