Deep Brain Stimulation

Not all children with primary dystonia respond to DBS, but for those most suited to DBS, the therapy can reduce symptoms by 60 to 90 percent. Many children will have a noticeable, sometimes dramatic improvement in function, quality of life, and joint deformity. Occasionally, a child who has been wheelchair-bound may recover the ability to walk. Improvement isn’t immediate, though — it typically takes six to 12 months to see a substantial difference.

It’s important to note that DBS is not a cure, and abnormal movements will return when the system is turned off. This is true for all treatments for dystonia, not just DBS.

Under FDA criteria, DBS is indicated for children 7 or older. Children whose primary dystonia affects the whole body and is not controlled well by medications are the best candidates for DBS therapy. DBS can be used for generalized dystonia, hemidystonia (affecting one side of the body), segmental dystonia (affecting two adjacent parts of the body), and cervical dystonia (affecting the neck muscles).

The children who do best with DBS tend to be younger and to start therapy before the symptoms cause permanent physical damage, such as joints that are fixed in place. At Boston Children’s, children with primary dystonia are carefully evaluated by movement disorder neurologist Jeff Waugh, MD, PhD, and neurosurgeon Scellig Stone, MD, PhD, to determine whether DBS might be of benefit. Each child is further evaluated with an MRI of the brain and neuropsychology testing. Our team then meets to confirm that surgery is appropriate and to discuss its optimal timing.

Currently available treatments for dystonia include physical therapy, oral medications, botulinum toxin (Botox) injections to affected muscles, and neurosurgery. These treatments alleviate symptoms, but none provide a cure. Botox works best for dystonia that affects a single area or only a few body parts but is insufficient for dystonias that are generalized throughout the body. There are other drugs with a body-wide effect, such as baclofen, a muscle relaxant, and trihexyphenidyl (Artane), which can relieve stiffness, tremors, and spasms. However, these drugs do not benefit all children and can have unwanted side effects.

DBS therapy requires surgery to implant the neurostimulator, the leads, and the connecting wires (known as extensions). The surgery typically lasts several hours, while the child is asleep under general anesthesia, and requires a hospital stay.

The leads are inserted first, through a small opening in the skull, to a precisely targeted site within the brain. Usually, the extensions and neurostimulator are implanted and connected during the same procedure. (In rare cases, the extensions and the neurostimulator are implanted and connected in a separate operation.)

The neurostimulator usually isn’t turned on until the child has healed from the operation, typically four weeks after surgery. Once the device goes “live,” the settings will need to be tailored to each child. There is no “cookbook” for how DBS should be programmed, and every person’s ideal settings are different. This requires several follow-up visits — at first, every month after surgery, then every few months once the best settings have been determined.

The neurostimulator will need to be replaced every few years when its battery starts to run low. This is usually a minor outpatient operation. A rechargeable battery can be used in certain cases to lengthen battery life. The final DBS settings determine how much power output is needed and how long the battery will last.

Children with DBS systems need to follow some specific precautions; for example, they cannot have normal MRI scans, and there are situations in which the stimulator will need to be turned off. Your neurologist and neurosurgeon will review all these precautions with you.

As with any brain surgery and medical treatment, there are some risks to consider with DBS therapy. Your care team will discuss possible surgical complications and therapy side effects with you.