We are now entering an era of exponential growth in the clinical application of neuroimplant technologies. The proverbial ice was originally broken by cochlear implants – a digital inner ear that converts sounds into electrical impulses and transmits them directly to the auditory nerve. Many other devices have been used with some success outside of the brain, but the true revolution came when surgeons and neurologists got clearance to begin implanting wires deep inside the brain to treat Parkinson’s disease.
Now, 30 years later, over 100,000 people are walking around with what is called a ‘deep brain’ stimulator inside their bodies, known as deep brain stimulation (DBS). This device involves having a battery pack implanted in the shoulder and a lead – which runs from the shoulder, through the neck, up to the top of the scalp – implanted tens of millimetres inside the brain.
Here, it delivers high-frequency electrical impulses which have been shown capable of improving the symptoms of Parkinson’s disease, essential tremor, dystonia, OCD, Tourette syndrome, and medication-refractory epilepsy and depression.
Seemingly, every year there are new conditions for which this therapy proves beneficial and large research centres have their sights set squarely on mood disorders. This focus could have clear implications for how clinical psychologists and psychiatrists help their patients to manage treatment-refractory disorders.
Deep brain stimulation represents a departure from the ‘norm’
In clear contrast to traditional clinical psychology and psychiatry, DBS may seem designed to circumvent behavioural and pharmaceutical interventions upon which neurological specialties have relied for hundreds of years.
The clear question is whether deep brain stimulation is a ‘hammer seeking a nail’? Further, if it proves effective for such a broad array of neurological conditions, will it prevent us from ever understanding them fully? Finally, without a complete understanding of neurological (particularly psychosocial) disorders, how will we be sure that we have identified the most safe and effective therapy?
Focus on treatment-refractory patients
For now, DBS is cleared for use in patients for whom less invasive and risky therapies have not been effective. For example, in February of 2008, the Food and Drug Administration approved the use of DBS to treat severe obsessive-compulsive disorder (OCD) with the condition that candidate patients have failed to control their disorder with at least three selective serotonin reuptake inhibitors (SSRIs).
Conditional clearance of DBS presents opportunities for clinicians to study and understand the underlying patient-specific complexity of a disorder prior to bringing the ‘hammer to the nail’. Particularly for mood disorders which often do not respond well to traditional therapies, this process is critical because of the subject-specific differences in behavior, underlying causes of disorder, and the high co-occurrence of other health concerns.
Efforts to increase disorder and patient specificity in the application of DBS
Researchers recognise that, as a tool, DBS is still too general to be effective for all treatment-refractory conditions. Until it is, clinicians who use it prematurely may be prevented from gaining an adequate understanding of the underlying mechanisms of the disorder they wish to treat.
Therefore, the most desirable future for DBS research, is that we seek to first understand the brain of the patient and to predict the device parameters which will work best on a patient-to-patient basis. This approach provides therapists and clinicians with an exploratory window into the complexity that each patient presents in the clinic and preserves their prerogative to identify the best possible course of treatment.
DBS should be supported by other treatment or diagnostic modalities
Every good clinician or therapist fears that they will not have the right tools to help their patients. DBS represents just enough of a departure from the normal course of treatment for many neurological conditions that some may feel that their practice is threatened by its success. Far from being time to ‘hang up their hat’, the emergence of new therapies represents an opportunity to enhance our understanding of the therapy using pre-existing methods. Further, many of these traditional methods can or should be used alongside DBS.
There are many examples of this in practice: diagnostic imaging improves the ability of surgeons to place implants correctly, therapy or psychiatric methods may be required to treat remaining symptoms over which DBS has little or no influence, and counselling remains valuable in ensuring patients and their families adjust well to any possible psychosocial changes (positive or negative) post-implant.
The end goal of healthcare is to improve a patient’s quality of life. Restoring a sense of well-being to the suffering individual and to their loved ones should always be the focus. Neuroimplant technologies represent a new frontier in that effort.
Image credit: Freepik
Dr Clayton Scott Bingham is a Postdoctoral Fellow at Case Western Reserve University School of Medicine. You can connect with him on Twitter @claytonsbingham.