How do you treat traumatic brain injury? One symptom at a time

Functional Connectivity in the Mouse Brainstem Represents Signs of Recovery from Concussion

Mild traumatic brain injury (mTBI) is one of the most frequent neurological disorders. Diagnostic criteria for mTBI are based on cognitive or neurological symptoms without fully understanding the neuropathological basis for explaining behaviors. From the neuropathological perspective of mTBI, recent neuroimaging studies have focused on structural or functional differences in motor-related cortical regions but did not compare topological network properties between the post-concussion days in the brainstem. We investigated temporal changes in functional connectivity and evaluated network properties of functional networks in the mouse brainstem. We observed a significantly decreased functional connectivity and global and local network properties on post-concussion day 7, which normalized on post-concussion day 14. Functional connectivity and local network properties on post-concussion day 2 were also significantly decreased compared with those on post-concussion day 14, but there were no significant group differences in global network properties between days 2 and 14. We also observed that the local efficiency and clustering coefficient of the brainstem network were significantly correlated with anxiety-like behaviors on post-concussion days 7 and 14. This study suggests that functional connectivity in the mouse brainstem provides vital recovery signs from concussion through functional reorganization.

Neuromodulation Treatments for Mild Traumatic Brain Injury and Post-concussive Symptoms

PURPOSE OF REVIEW

Mild traumatic brain injury (mTBI) can result in prolonged post-concussive symptoms (e.g., depression, headaches, cognitive impairment) that are debilitating and difficult to treat. This article reviews recent research on neuromodulation for mTBI.

RECENT FINDINGS

Transcranial magnetic stimulation (TMS) is the most studied neuromodulation approach for mTBI (four studies for depression, four for headache, one for cognitive impairment, and two for global post-concussive symptoms) with promising results for post-concussive depression and headache. Transcranial direct current stimulation (tDCS) has also been evaluated (one study for post-traumatic headache, and three for cognitive impairment), with more mixed results overall. TMS appears to be a potentially promising neuromodulation treatment strategy for post-concussive symptoms; however, integration into clinical practice will require larger sham-controlled randomized trials with longer and more consistent follow-up periods. Future studies should also explore new stimulation protocols, personalized approaches, and the role of placebo effects.

Use of Repetitive Transcranial Magnetic Stimulation in the Treatment of Neuropsychiatric and Neurocognitive Symptoms Associated With Concussion in Military Populations

BACKGROUND

Since the year 2000, over 342 000 military service members have experienced a concussion, often associated with chronic neuropsychiatric and neurocognitive symptoms. Repetitive transcranial magnetic stimulation (rTMS) protocols have been developed for many of these symptoms in the general population.

OBJECTIVE

To conduct a scoping review of the literature on rTMS for neuropsychological and neurocognitive symptoms following concussion.

METHODS

PubMed and Google Scholar search engines identified 9 articles, written in English, corresponding to the search terms TBI or concussion; and TMS or rTMS; and depression, PTSD, or cognition. Studies that were not therapeutic trials or case reports, did not have neuropsychiatric or neurocognitive primary outcome measures, or described samples where 80% or more of the cohort did not have a TBI were excluded.

RESULTS

There were no reports of seizures nor difference in the frequency or quality of other adverse events as compared with the broader rTMS literature, supporting the safety of rTMS in this population. Support for the efficacy of rTMS for the treatment of neuropsychiatric and neurocognitive symptoms, in this population, is limited.

CONCLUSIONS

Large-scale, innovative, neuroscience-informed protocols are recommended to elucidate the potential utility of rTMS for the complex neuropsychiatric and neurocognitive symptoms associated with military concussions.