Studies have shown that working the brain can help alleviate the degradation of nerve cells in those with Alzheimer's. Learning a new language, or studying a new skill like cooking, sewing, or playing an instrument can protect the brain.
Currently, there is research surrounding deep brain stimulation and its ability to 'rescue' nerve cells. A study published by Johns Hopkins Medicine focused on 6 people with early Alzheimer's. Doctors had implanted a device that would send consecutive electrical signals directly to the hippocampus (memory area) in the brain to increase neuronal activity. Thirteen months after the device had been inserted, patients had shown a significant 15 to 20 percent increase in glucose metabolism, which is used as an indicator of neuronal activity. These results were then compared to those Alzheimer patients who were taking the leading medication marked to fight AD progression and showed to have better outcomes and more promise for the future of the patients.
This shows some very exciting progress in the search to end Alzheimer's; now affecting roughly 5.4 million people, which is about 1 in 8 individuals and is the sixth-leading cause of death in the United States.
www.alz.org (1st picture)
www.hopkinsmedicine.org
www.technologyreview.com (2nd picture)
Happy Veterans Day!
Hey, great post but I have a two questions. 1)Is the electrical signal constant throughout one's life or is it stimulated sporadically?
ReplyDelete2)When the electrodes stimulate the thalamus for enhanced motor function how are the other functions of the thalamus effected? I know the thalamus sends sensory signals and effects sleep, how are these affected?
To help answer Nicks question: Mayoclinic at this website, http://www.mayoclinic.com/health/deep-brain-stimulation/MY00184 says that "The amount of stimulation delivered by the electrodes is controlled by a pacemaker-like device placed under the skin in your upper chest." With this said, it sounds like the its stimulated constantly throughout the patients life, BUT just at different intervals depending the individual patient. If the device is like an typical heart pacemaker, how would the electrodes know specifically when to fire? Do you think that the electrodes in the brain can also receive some type of input?
ReplyDeleteI think that it must be able to receive some type of input from the brain. I looked up how a cardiac pacemaker works on the National Heart Blood and Lung webiste )http://www.nhlbi.nih.gov/health/health-topics/topics/pace/howdoes.html), and what it said was that the cardiac pacemaker had a generator with a computer, a battery, and two electrodes. What happens with this type of pacemaker is that the electrodes can sense the electrical activity of the heart, your temperature, and how fast you're breathing. Then the electrodes send the data to the computer in the generator, which decides whether or not to adjust the heart rate.
DeleteI think that the DBS device is probably similar-- that way it could detect how much electrical activity the patient's brain had. In Alzheimer's patients, the activity would decrease, so then the DBS device would send pulses to the brain, ramping up the electrical activity to slow the degeneration due to non-use.
To answer Aprils question, the frequency at which the signals are sent would have to be a rhythmic, continuous pattern. It's not really a matter of knowing when to send the signal, because someone who is diagnosed with Alzheimer's will always have to be protecting their brain against degradation. Therefore, stimulation will always be needed. The strength of the stimuli will eventually be reduced over time with progression, however, the device will constantly be firing.
ReplyDeleteTo answer Nick's second question, part of the implantation procedure involves the doctors 'testing' the areas of the thalamus. That way, they are only stimulating a specific section. During the procedure, the electrodes are put in place and send stimuli while the patient is awake. He/she will tell the surgeons what they are feeling and where to avoid placing the electrodes in the wrong place. Then, the patient is put to sleep while a neurophysiologist comes in to monitor the patients' brain activity with stimulation. Once the doctors feel like they have eliminated any other risks, they place a 'clamp' on the electrode to hold it in place and close up the wound. This website is very helpful and explains more in detail this procedure and how the surgeons are able to avoid stimulating the wrong part of the brain. http://www.neurosurgery.pitt.edu/imageguided/movement/stimulation.html
To continue what Caitlin was saying, the DBS device is similar to a cardiac pacemaker. Unfortunately, an Alzheimer's patient can never really 'get rid' of the disease. Therefore, use of the DBS device would need to be continuous until the pateints' neurons are considered healthy and he/she can be able to sufficiently take care of themselves. At this point, the doctors can go in and reduce the strength of the signals.
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ReplyDeleteIt is interesting that the DBS device is tested while the patient is conscious to see what stimulation occurs depending on the placement of the electrodes. However, one complication that I found from the external link provided (http://www.neurosurgery.pitt.edu/imageguided/movement/stimulation.html), is that because different brain functions are located in close proximity of one another, there can be unwanted stimulation occurring as a side effect even after the wiring was thought to have been placed correctly. And in those cases, electrodes would have to be repositioned. Due to the invasiveness of this procedure where even the battery wiring was hidden under the skin beneath the side of the head, neck, and chest, it would be a hassle to have to reposition the electrodes and perform open brain surgery again. Also, it would be a hassle because the battery is said to last 3-5 years leading to replacement of the battery that was placed below the skin.
ReplyDeleteApparently the idea is that if you don't use it, you lose it! In the second paragraph of the article it is mentioned that doing things like "learning a new language" or "studying a new skill" can ward off Alzheimer's disease. This proposes that by stimulating your brain by doing novel things, you are in fact stimulating populations of neurons that would otherwise be at risk of Alzheimer's if you were NOT to be learning or doing new things. While I'm sure there is a strong genetic link in this disease, it seems that if you want to avoid implanting a large electrode into your brain to manually stimulate your neurons, you should do it on your own!
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