PARKINSONISM AND OTHER MOVEMENT DISORDERS

        

                Movement disorders are neurological conditions that affect the speed, fluency, quality, and ease of movement. Abnormal fluency or speed of movement (dyskinesia) may involve excessive or involuntary movement (hyperkinesia) or slowed or absent voluntary movement (hypokinesia). The commonest movement disorder is Parkinson’s disease which manifests with tremors, rigidity, slow movement (bradykinesia), poor balance, and difficulty in walking. It affects 1 – 2% of people above 60 yrs but in India it is seen in younger people also (upto 15%). Treatment of movement disorders like Parkinsonism is predominantly by drugs and drugs are very effective in most cases. But a good number of patients either come out of good control in the long term or develop side effects of drugs. Such patients are surgical candidates. Previously ablative (destructive) surgeries like pallidotomy were used for this problem but presently the treatment of choice is subthalamic nucleus deep brain stimulation (DBS). Ablative surgeries are permanent and non reversible and the side effects are much more and so ablative surgeries are not much practiced.

Indications for DBS in Parkinsonism:

             1. Advanced Parkinson’s disease with disabling motor fluctuations and dyskinesias refractory to drug changes.
              2. Levodopa induced dyskinesias.
              3. Medication refractory symptoms with significant disability and interference with daily activities including writing, feeding, dressing, etc.
              4. No significant cognitive impairment and no major psychological problems.
              5. 10 years after diagnosis.
              6. Patients understand and accept therapy. 

Parkinson”s Disease (PD) can be said to be having three stages. 

Stage 1 is early PD where most of the people can be managed with medical treatment; however 20% of the patients (especially with tremors) who do not respond to conservative treatment can be offered surgery. 

Stage 2 of PD is where medical treatment starts loosing its efficacy, is associated with side effects like hallucinations and dyskinesias and causes wide fluctuations of off and dyskinetic state. Surgery is very useful at this stage. This stage occurs after 5 or more years of disease. Besides dyskinesias and motor fluctuations, other indications include severe pain and hallucinations.

Stage 3 of PD is the most advanced stage when the patient is virtually bed bound and barely responds to medical treatment, and has significant side effects. Surgery may or may not be possible in this case.
      

                 Deep brain stimulation (DBS) for Parkinsonism involves stimulating the subthalamic nucleus (STN) with specially made electrodes. The surgery is done under local anaesthesia. Surgery for Parkinsonism usually resolves tremor, dyskinesias, pain and hallucinations and symptoms which are improved by drug therapy are maximally improved with surgery. Tremor improves by 80%-100%, slowness (Bradykinesia) by 50%-60%, stiffness (Rigidity) by 50%-70%, gait, freezing, and balance 50%, dyskinesias & dystonia  (drug induced) 80%- 90% and motor fluctuations are virtually eliminated. Independence and quality of life are substantially improved. Complications include haemorrhage (2-3%), Infection (1 -3%), mechanical breakage (1-5%) and cognitive decline (2%).

                 DBS is also done in other movement disorders like Dystonia (including cervical dystonia) and in cases of chronic pain.

                 Recently deep brain stimulation of the nucleus accumbens is being done in cases of intractable alcoholism.