Improved function after deep brain stimulation for chronic, severe traumatic brain injury

Past studies have found

1.7 million Americans are treated for a traumatic brain injury (TBI) every year. Most TBI’s are mild but those who have moderate or severe injuries are more likely to have long-term challenges and disabilities including problems controlling behavior and emotions, difficulty with thinking and memory, and impaired movement and sensation. Impaired emotional and behavioral self-control is common in individuals with TBI. The ability to control one’s emotions and behavior is critical in order to adapt to deficits, manage stress, and rehabilitate from injury. Unfortunately, there are few treatments to help restore these abilities (called “executive functions”).

This study

This study focused on how to address difficulties in executive function through use of Deep Brain Stimulation (DBS). DBS is a procedure by which small electrodes are implanted in the brain; these electrodes deliver measured electrical impulses to specific brain areas. DBS electrodes transmit electrical signals nearly all the time while the device is on.

In the current study, four individuals with a history of severe TBI (between 6-21 years earlier) were implanted with electrodes in the nucleus accumbens, an area of the brain known to be related to motivation and goal-directed behavior. Each of the participants was impaired in their ability to function independently and showed deficits in executive functioning. All of the participants were receiving medication to address mood difficulties but with limited results. Researchers expected that improved ability to engage in self-control would allow the person to adapt more favorably to sensory, motor, and cognitive impairments, therefore, allowing increased independence in a variety of domains.

Two-years after implantation, three of four participants achieved clinically significant improvement in independent functioning. Moreover, all four participants showed improvement in their adjustment (related to mood, initiation, appropriateness of social interactions, and self-awareness). Notably, cognitive abilities improved and then later declined. It is thought that cognitive improvements were not sustained because of lack of continued training. Two of four participants required less assistance in their daily activities and showed greater ability to adapt to and cope with disability and daily stressors. Three of four participants increased their involvement in activities outside of the home. Improvements were also subjectively observed in areas of alertness and engagement.

Results of this study suggest that DBS targeting the nucleus accumbens can be performed safely for individuals with severe disability due to TBI. The greatest benefits of DBS for this population will most likely occur when stimulation is received concurrent with rehabilitation and enhanced engagement in daily activities. Because this was not a controlled study, it is not possible to know if the improvements were due to the deep brain stimulation or to another factor, such as a placebo effect.

Who may be affected by these findings?

Individuals with TBI, their loved ones, and individuals with diminished executive functioning abilities due to other conditions (e.g. mental illness).

Caveats

This is the first study examining the use of DBS of the nucleus accumbens to address executive functioning difficulties in individuals with chronic TBI. Continued research is needed to further validate this treatment.

Bottom Line

DBS may be an effective treatment for the management of executive functioning difficulties in individuals with chronic TBI. Continued research is needed to confirm the safety and utility of this treatment.

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