Alzheimer’s disease is the most commonly occurring form of dementia, which involves loss of memory, language, problem-solving capabilities, and several other abilities related to your thought process. This geos on to such an extent that your daily life is utterly disrupted.
The single significant risk factor when it comes to Alzheimer’s disease is ageing. Drugs that are used to treat Alzheimer’s offer some patients a tad bit of relief from symptoms. That said, they do not halt its unavoidable progress. Hence, researchers are taking a look at newer therapies that might be able to successfully slow down the progression.
One such therapy is deep brain stimulation or DBS.
Brain stimulation therapies make use of electricity to successfully ‘turn on’ or ‘turn off’ specific activity in the brain.
What is Deep Brain Stimulation and How Does It Work?
Deep brain stimulation is an invasive surgical procedure. This means the procedure involves brain surgery. During DBS, a pair of electrodes is implanted in specific regions of your brain. Small generators (resembling pacemakers) that will eventually control the activity of the electrodes are implanted in the chest region.
Before the surgery, an MRI (magnetic resonance imaging) scan of your head and brain will be conducted. You will be conscious and awake during the procedure, with the administration of a local anaesthetic to ensure that your head stays numb. The brain will not feel pain either.
Then the surgeon will drill two tiny holes in your skull and use the MRI images to place the electrodes in the precise place. After this, you will be administered general anaesthesia (to ensure that you are asleep) so that the surgeon can implant the generator and the wires that successfully connect them to the electrodes. Post-surgery, there is a continuous flow of brain stimulation. Your doctor will customise the frequency of the stimulation as well as its intensity.
DBS for Alzheimer’s
DBS was initially used to reduce the occurrence of tremors, uncontrollable movements, and stiffness, which are symptoms of Parkinson’s disease. Researchers then began to look at this procedure’s efficacy in Alzheimer’s after one patient reported improvement in memory after receiving DBS treatment to tackle obesity.
Since then, individuals who are diagnosed with Alzheimer’s and treated with DBS have demonstrated positive results. Researchers are still seeking the most optimum way to use DBS for Alzheimer’s disease: which sections of the brain need stimulation, the intensity of the stimulation, and the duration of the stimulation.
Neural Pathways Involved
DBS when used for Alzheimer’s targets regions of the brain that include significant neural pathways such as:
- VC/VS (ventral capsule/ventral striatum), which is responsible for cognition (involving logic, remembering, and thinking) and behaviour
- ILN (intralaminar thalamic nucleus), which is a vital component when it comes to cognitive function.
- MTN (midline thalamic nuclei), which plays a significant role in memory
- NBM (nucleus basalis of Meynert), which is an integral part of a vital pathway related to memory and cognition
Researchers do not precisely know how DBS works when it comes to combatting symptoms of Alzheimer’s. According to one theory, stimulation helps in balancing the network of nerves that may gone out of sync. Another theory suggests that DBS successfully resets unstable nerve movements. According to yet another theory, DBS reduces the level of plaques that are toxic to the nerves in certain key regions of your brain.
How Effective Is DBS?
Earlier conducted studies suggest that DBS is indeed a promising treatment. Its efficacy depends on factors such as the stage of the disease and the specific plan of treatment (targeted brain region, frequency of stimulation, and more).
Usually, DBS is most effective when used during the early stage of Alzheimer’s. Patients who experience a late onset of Alzheimer’s may experience only a mild benefit from DBS: they seem to decline more gradually. Those with early-onset Alzheimer’s (those clinically diagnosed before age 65) demonstrate no benefit.
Complications, Side Effects, and Outlook
Potential complications arising from surgery include infection, bleeding, and hardware failure. Other complications generally relate to the intensity of the voltage:
- Increase in blood pressure
- Faster heart rate
Figuring out the best stimulation frequency (which varies across individuals and type of treatment) can help in easing of below-mentioned side effects.
- Stroke or bleeding in the brain
- Mood fluctuations
- Trouble while sleeping
In one specific study of DBS for Alzheimer’s disease, some patients had seizures, fainting, and falls. All these side effects are similar to the ones you may experience while you take certain medications for Alzheimer’s.
To Sum It Up:
Alzheimer’s is a form of dementia, involving loss of memory, language, and problem-solving capabilities. DBS has shown positive outcomes on those with Alzheimer’s disease, although the surgical procedure was initially meant for those with Parkinson’s. The precise way in which DBS benefits those with Alzheimer’s is not yet known to researchers. In addition, there may be certain complications and side effects, which can occur after almost any surgery.