“Movement disorders are disorders due to neurological pathology affecting the fine muscular movements of the body and interfere with their quality and quantity”.
The basal nuclei control our muscular movements by influencing the cerebral cortex. It assists in regulation of the voluntary movements and the learning of the motor skills. Basal nuclei influence the skilled cortical motor activities e.g. motor activities we use in writing the letters of the alphabets, drawing a diagram, passing a football, even using the vocal cords in talking and singing and using the eyes muscles when looking at an object. The basal nuclei not only influence the execution of a particular movement but also prepare for the movements.
Thus, any disorder in the basal nuclei leads to movement disorders. These are of two types, namely
- Hyperkinetic Disorders: These disorders are those in which there are excessive and abnormal movements such as seen with chorea, athetosis and ballism.
- Hypokinetic Disorders: These include those in which there is a lack or slowness of movement. Parkinson disease includes both types of motor disturbances.
Movement disorders are seen in many forms. Some of them include
- Chorea: In this condition the patient exhibits involuntary, quick, jerky, irregular, movements that are nonrepetitive. Swift grimaces and sudden movements of the head or limbs are some of the good examples of this condition.
- Sydenham Chorea: It is a disease occurring in the childhood in which there are rapid, irregular, involuntary movements of the legs, arms, face and trunk. This disease is usually associated with rheumatic fever. The antigens of the streptococcal bacteria are similar in structure to the proteins present in the membranes of the striatal neurons. Antibodies present in the host bind them and also attack the membrane of the neurons of the basal ganglia. This leads to production of choreiform movements which are fortunately transient and there is full recovery as well.
- Hemiballismus: It is the form of involuntary movement confined to the one side of the body. This movement usually occurs in the proximal extremity muscles and the limb suddenly flies about out of control in all directions. The lesion occurs in the opposite sub thalamic nucleus or its connections which is usually a small stroke; it is in the sub thalamic nucleus where smooth movements of different parts of the body are integrated.
- Athetosis: It consists of slow, sinuous, writing movements that most commonly involve the distal segments of the limbs. There is degeneration of the globus pallidus which occurs with a breakdown of the circuitry involving the basal nuclei and the cerebral cortex.
- Dystonia: In dystonia there are involuntary muscle spasm occurred due to neurological muscle disorder. These movements can affect limbs, vocal cord, eyelids etc.
- Huntington Disease: In this disease choreiform type of movements occur which are of flickering type.
- Parkinson Disease: Here tremors at rest, rigidity and bradykinesis occur.
- Tourette syndrome: In this disease there are involuntary movements of vocal cord occurred.
- Akathisia: In this condition there is motor restlessness,
- Tardive dyskinesia: This condition involves involuntary movements of the tongue, lips, neck, truck and limbs.
There are likewise lots of other diseases which cause abnormal movements of the parts of the body.
This includes treatment of the specific disease which has led to the involuntary movements.