Neuromodulation techniques, as opposed to standard pharmacological methods, have enabled the direct and localized revitalization of malfunctioning neuronal circuits. Treatment via neuromodulation has been applied to various conditions including neurological disorders, chronic pain and, as of most recently, in disorders of consciousness.
In a letter to the editor published in July 2016 in the journal Brain Stimulation, UCLA associate professor of psychology and neurosurgery and lead author Martin Monti presented a case in which low intensity focused ultrasound pulsation (LIFUP), a neuromodulation technique, helped a 25-year-old patient recover from a coma. This report was the first to describe the utilization of LIFUP in treating a disorder of consciousness.
The patient, following a severe brain injury, had not fully recovered from his coma and had fallen into a disorder of consciousness, specifically the minimally conscious state, when he was recruited into the clinical trial led by Monti. On the day prior to the neuromodulation therapy, the patient, reduced to his minimally conscious state, presented a Coma Recovery Scale-Revised (CRS-R) rating of 15. Shortly before the administration of LIFUP, the patient’s CRS-R rating was noted to have worsened to a rating of 14.
Utilizing a device containing an ultrasound transducer, the research team administered sonications at a repetition frequency of 100 Hz a total of 10 times with each sonication lasting 30 seconds. The transducer, secured to the right side of the patient’s head, was positioned so that the patient’s thalamus was stimulated. An area commonly found diminished in patients suffering from a post-coma disorder of consciousness, the thalamus, functions as a central regulator of sensory information and motor control. It receives sensory signals and relays them to the cerebral cortex.
Following the sonication of the patient’s thalamus, the research team conducted two additional assessments of the patient’s level of consciousness to determine the efficacy of the neuromodulation treatment. Although the patient presented a CRS-R of 13 shortly after the sonication, he sufficiently recovered to a CRS-R of 17 the day after the procedure and began to regain some motor responses and vocalizations. Three days after the LIFUP, the patient was not only able to fully comprehend language, but also respond to commands and communicate by nodding and shaking his head. Five days after the LIFUP, the patient recovered sufficiently enough to stand up and attempt to walk.
The researchers, however, note in their report that at the time of publication they could not be certain that the LIFUP was responsible for the patient’s unexpected rehabilitation due to the lack of sufficient evidence for a causal link. Whether this patient was able to serendipitously recover from the minimally conscious state is still unclear. Nevertheless, the researchers intend to continue testing the LIFUP on other patients as part of their clinical research. If the neuromodulation technology proves to be equally effective with other patients, the researchers speculate that the transducer may be further developed into a portable device for wide usage and accessibility.
Even in its current form, the LIFUP technique is non-invasive and capable of the neuromodulation of deep brain nuclei, including those in the thalamus.
Other neuromodulation techniques such as deep brain stimulation and transcranial direct current stimulation, have a number of limitations. Deep brain stimulation, an invasive procedure, requires surgery and the implantation of electrodes.
While the transcranial direct current stimulation is non-invasive, it is limited in its ability to stimulate deep brain nuclei. Lacking the drawbacks of these two neuromodulation techniques and potentially capable of even treating a disorder of consciousness, the LIFUP shows therapeutic promise and is certain to be the subject of further studies.