quarta-feira, 23 de novembro de 2011

Implantes cerebrais podem ajudar os pacientes psiquiátricos

Brain implants may help psychiatric patients
Operating on psychiatric patients' brains has come a long way from the lobotomies depicted in One Flew Over the Cuckoo's Nest. Picture: AP
November 23, 2011 - DEEP brain stimulation may sound like a scary concept but is emerging as a revolutionary way to treat psychiatric patients.
The therapy, which involves a tiny implant being embedded in the brain, has already had great success in controlling limb tremors in thousands of people with Parkinson's disease.
Scientists in Australia are now working on revamping the electrodes inside the implants to use in people with mental disorders.
But this latest form of psychosurgery is a long way from the days of the notorious lobotomies carried out decades ago which left many psychiatric patients like zombies.
The implants work in a similar way to how cochlear implants help deaf people hear again, by firing off electrical signals to the brain.
The theory is that you can shut down areas causing symptoms related to conditions such as Parkinson's, epilepsy, obsessive compulsive disorder (OCD) and chronic depression.

How the implants are being tested
Professor Hugh McDermott, of the Bionics Institute in Melbourne, helped develop the cochlear implant and has been working on developing the technology for use in blind people and others with movement and psychiatric disorders.
However, he says the implants are not a cure and should only be used in patients with severe conditions who have had no luck with traditional treatments like medication.
"The idea is that electrical stimulation can make neurons in the brain fire, or suppress them from firing. It's a matter of choosing the right neurons to get the right therapeutic benefits," Professor McDermott said.
While 75,000 Parkinson's patients around the world including hundreds in Australia have received brain implants, using the devices in psychiatric patients is still experimental.
For the past few years Professor McDermott has worked with Melbourne neurosurgeon Richard Bittar to test them in a handful of Australian patients.
Three had obsessive compulsive disorder (OCD), one epilepsy and five severe depression.

'Some are more or less completely cured'
Associate Professor Bittar says while it is early days and more needs to be done to improve the implants, the results have been promising.
"I'm very encouraged. I think with this type of technology our results can only get better," he said.
"One lady who was housebound, packed up her bags and went travelling after the surgery. She was over the moon. She still is."
The patients with depression received their implants in the past four years.
Unlike traditional medications whose effects can subside after long periods of use, Associate Professor Bittar has noticed the implants continue to benefit his patients.
For some of the OCD patients the implants have had just as big an impact.
"About half get a dramatic benefit and some are more or less completely cured," said Professor McDermott, who discussed his work at the International Conference on Medical Bionics held on Victoria's Phillip Island.
"They go from institutional care to a relatively normal life where they can have a job and pretty much normal social interactions again.
"It's a miraculous benefit for those people. But it doesn't do that for everybody at the moment."
Epilepsy is proving trickier to treat as seizures associated with the condition start in different parts of the brain and spread, making it hard to work out where to put the implant.
"Epilepsy certainly looks like one of the harder conditions to treat whereas things like OCD and Parkinson's we have a much more well-defined area in the brain to target to give a better result," Associate Professor Bittar said.

Wires run from skull to power pack
While the implants help some patients, the devices are still considered fairly crude.
Surgeons use a hole in the skull to insert the implants in a certain part of the brain, depending on the disorder they wanted to treat.
The implants are connected to a series of wires running from the skull under the skin down the neck to a power pack in the chest or abdomen.
But some patients are unhappy about the rectangular power pack protruding under their skin, while the wires connected to the brain implant sometimes break as a result of normal head and neck movement during the day.
It can also take time to work out the right amount of electrical stimulation needed, and there can be side effects including speech and balance problems.
Scientists including Professor McDermott are aiming to develop wireless versions of the implants similar to the cochlear ones.
And instead of having a battery pack implanted in the chest, a rechargeable battery would sit behind the recipient's ear.

'We don't want to open the floodgates'
Associate Professor Bittar says a slow and careful approach to the development and use of the implants is essential.
"We don't want to open the floodgates for this type of thing," he said.
"It's very important you go about this in a responsible fashion, particularly in view of what happened all those decades ago with the original form of psychosurgery.
"We have all learned the lessons from that era and most of us are very keen on avoiding making the same mistakes again." Fonte: News.au.

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