Parkinson disease is one of the
major degenerative neurological disorders, Alzheimer being the other. It affects both men and women who are usually
over the age of 40 years. This disease is predominantly characterized by
movement problems where in the people with Parkinson disease, brain cell loose
ability to produce enough dopamine required for normal movement. The scientist
still hasn’t found the cause of malfunctioning of dopamine producing
neurons. Treatment for Parkinson
disease is different based on person symptoms, age and person reaction to drugs.
If the drug fails to control
symptoms, deep brain stimulation surgery is one of the choices for Parkinson
disease. This surgery is done by making a hole in the skull bone and electrode
is place into the thalamus, and electrical stimulation is send in hoping to
find the targeted area where tremor can be stopped, but at the same time side
effects are also observed. If the results obtain are good the electrode is left
in place and wound is close.
One of the studies done at veterans’
hospitals across the country showed that patients who had gone through this
surgery felt better and also improved significantly than the patient who
received medical/drug treatment.
But according to Dr Weaver, 40% of the patient who has undergone this
surgery had experienced at least one adverse effect, like the infection around
where the electrode is placed so until the infection is cured patient had to
remove the electrode. Other
studies showed that intracranial bleeding can occur after surgery, and also
some patient don’t benefit much because stimulator are not correctly adjusted.
According to the VA Hospital in
Chicago, data shows that the people who underwent the path of surgery, they are
still benefiting from the electrodes installed after 5 years, some even after
10 years though battery operating the simulators had to be replaced over time.
Reference:
Interesting post Anjita. So from my understanding and correct me if I'm wrong, in Parkinson's disease, the brain lacks dopamine due to the degeneration of cells and as a result normal brain function becomes compromised. This causes the tremors and other symptoms to arise. The part I'm not clear on though is how the electrical stimulus so easily replaces the loss of dopamine. Does dopamine normally cause an activation comparable to that of an electrical stimulus? I suppose the answer to that would have to be a yes or else the electrode surgery would not work so well. But also you mentioned that when the electrode was inserted properly the tremors stopped, so was that a result of the electrical stimulus replacing the dopamine function or was it just concealing the symptom, sort of like a band-aid: the wound is still there and may still be infected but we don't worry so much because it's been covered up?
ReplyDeleteFrom what I understand about Parkinson treatment, is that L-dopa is used as a fairly common treatmet. It essentially mimics the actions of dopamine, but the problem is after some time the effects of L- dopa are dampened and the drug no longer becomes and effective treatment. I wonder what role the immune system may play in the long term desensitization of L-dopa. The immune system probably recognizes the drug over over time and is able to react faster and minimize the effects of the drug.
ReplyDeleteTo answer question of brynee, the electrical stimulus do not replaces the loss of dopamine, like you mention it is actually sort of like a band aid, because we cant replace the dopamine. Nerve cells use a dopamine to help control muscle movement. When the nerve cells in the brain that make dopamine are slowly destroyed, we get PD. Due to decrease amount of dopamine the nerve cells in that part of the brain cannot properly send messages which leads to the loss of muscle function. So basically what Deep brain stimulation is doing is targeting the area where the movement disorder originates. A small electric pulse stimulates that precise part of the brain, which is supposedly stop the tremor, abnormal movements or rigidity. It is almost similar heart pacemaker. We still don’t know why the stimulation works, but there has been some hypothesis that it normalizes aberrant activity in the sub-thalamic nucleus, areas of the brain that are the primary targets for deep brain stimulation in Parkinson’s disease.
ReplyDeleteTo answer question of Samiat, as the Parkinson Disease progresses the effects of L-Dopa wear off. I don’t think it has anything to do with our immune system.
It might be possible that as increasing loss of dopamine-producing nerve cells the medication cant compensate for it. I did some research but couldn’t find much on it. We still don’t know definite explanation for what causes the wearing off of the medicine.