Deep brain stimulation may help Parkinson’s patients
Washington: Two studies by University of Alabama at Birmingham researchers have suggested that deep-brain stimulation (DBS) may stop uncontrollable shaking in patients with Parkinson’s disease and essential tremor by imposing its own rhythm on the brain.
DBS uses an electrode implanted beneath the skin to deliver electrical pulses into the brain more than 100 times per second. Although this technology was approved by the Food and Drug Administration more than 15 years ago, it remains unclear how it reduces tremor and other symptoms of movement disorders.
With the help of electroencephalography or EEG — electrodes placed on the scalp — study authors used new techniques to suppress the electrical signal associated with the DBS electrode. That enabled the first clear, non-invasive EEG measurements of the underlying brain response during clinically effective, high-frequency brain stimulation in humans.
The results showed that nerves in the cerebral cortex, the outer layer of the brain, fire with rapid and precise timing in response to individual stimulus pulses. This suggests that DBS may synchronize the firing of nerve cells and break the abnormal rhythms associated with involuntary movements in Parkinson’s disease and essential tremor.
The newly identified rhythm was captured during effective DBS treatment, so it could represent a new physiological measure of the stimulation dose, said the authors. If validated, such a yardstick could help to guide the fine-tuning of DBS stimulator settings in patients for more lasting relief, fewer side effects and less-frequent battery-replacement surgeries.
“Though it’s clear that more work is needed to better understand these initial observations, we’re very excited by our findings because they may provide a biological marker for improvement in the symptoms of these patients,” said Harrison Walker, M.D., assistant professor in the UAB Department of Neurology’s Division of Movement Disorders and lead author of the study.
In current clinical practice, stimulator settings are adjusted by trial and error, requiring careful observation of changes in symptoms over multiple clinic visits. But such immediate, visual feedback may not be available as DBS is applied to neurological or psychiatric conditions such as epilepsy, severe depression or obsessive compulsive disorder.
In these diseases, an effective dose measurement could be especially useful in optimizing DBS therapy.
In both studies, EEG data revealed that nerve cells in the cerebral cortex discharged about one one-thousandth of a second, or one millisecond, after each stimulus pulse was delivered into the brain.
The authors argue that this rapid response on the brain’s surface most likely represented “backfiring” along extensions of cortical nerve cells called axons that connect them to deeper regions within the brain where the DBS electrodes were placed. Interestingly, this rapid response on the brain surface was present in both studies, regardless of the stimulation target or the disease state of the patient.
Although prior studies had hinted at these brain responses, they were unable to measure them directly because of interference from the competing electrical signal emitted by the DBS pulse itself. Walker and his team reversed the polarity of the stimulation pulse, in effect subtracting the DBS signal and leaving only the EEG signal associated with the brain activity.
The new technique also enabled the researchers to show that the size of the brain response at one millisecond after a DBS pulse is dependent on the intensity or voltage of the stimulus pulse, and that larger brain responses were closely associated with improvement in tremor.
“While early, this work has tremendous implications for the understanding of brain mechanisms responsible for a number of neurological and psychiatric diseases,” said co-author Barton Guthrie, M.D., in the Division of Neurosurgery.
“Further studies are planned to confirm these measures and mechanisms and we believe this insight will soon make valuable contributions to the next generation of DBS treatments,” he added.
The studies were published recently in the journal Movement Disorders.
More from India
More from World
More from Sports
More from Entertaiment
- Vadodara: Policemen seen dancing with bar girls
- PM Modi speaks at Golden Jubilee celebrations of poet Dinkar’s works
- Zee Media Exclusive: Kangana, Madhavan talk about their film 'Tanu Weds Manu Returns'
- DNA: Harmful chemicals found in Maggi, Nestle India still in denial mode
- Coal scam: Naveen Jindal, Madhu Koda and others get bail
- One year of Modi govt: Arun Jaitley addresses press conference
- ISIS executes Syrian fighter using anti-tank rocket launcher
- CM Kejriwal shortlists 39 'unwanted' IAS officers in Delhi
- Zee Media Exclusive interview with Congress leader Kamal Nath
- DNA: Modi-led NDA govt's hits and misses in one year
- Columbia student takes rape-protest mattress to graduation
- Rajasthan: Gujjars revive reservation agitation, block rail track
- J Jayalalithaa sworn-in as Chief Minister of Tamil Nadu
- Mumbai: One injured in shootout at Film City
- Delhi: Car catches fire after crash, one dead
- IPL 2015, Qualifier 2: CSK vs RCB - As it happened...
- Tanu Weds Manu Returns movie review: Brilliant execution, superb performance!
- India to soon have its own space shuttle!
- Kejriwal slams notification on LG's powers, says Modi running Delhi govt through back door
- PM Narendra Modi graces Digvijay Singh's son wedding reception
- Rahul Gandhi to pressurise govt to act on one-rank-one-pension issue
- CBSE 12th Results 2015: CBSE Board Cbse.nic.in & cbseresults.nic class 12th XII board exam Results 2015 date announced
- Businessman shot next to Amitabh Bachchan's shooting location in Mumbai Film City
- Goa Board SSC Exam Results 2015 announced
- ISIS close to buying nuclear weapon from Pakistan?
- Manohar Parrikar visits forward areas along LoC, reviews security situation
- RBSE 12th Science & Commerce Board Result 2015 declared
- West Bengal Board Class 10th Madhyamik Pariksha Results 2015 announced
- RBSE rajresults.nic.in & rajeduboard.nic.in 12th Results 2015: BSER Ajmer Rajasthan Board Class 12th XII Senior Secondary Science & Commerce Exam Results 2015 to be declared shortly
- There will be no delay in appointing CIC, CVC: Jitendra Singh