As discussed in prior posts on this blog, sleep alterations are commonly found after a concussion or other traumatic brain injury, both short term and in some cases long term. One of the most well documented impacts of concussion, also discussed in prior posts, is an increased risk of mood disturbances, including depression, increased anxiety and increased risk of suicide. In recent years researchers have turned to sleep studies to explore the connection between these symptoms.
There is substantial evidence in the literature of the role healthy sleep plays in the “consolidation” of emotional memories. At first blush, this research is counter-intuitive. If sleep “consolidates” emotional memories, doesn’t this have the potential to increase rather than decrease mood disturbance? The answer appears to be that, although sleep preserves memory of events associated with emotional experience, at the same time it weakens the emotional “charge” coating the experience (referred to in the literature as “valence”) in a process called “habituation.” As one researcher hypothesized, “we sleep to forget the emotional tone, yet sleep to remember the tagged information.”Read More
A review published in the September 2017 issue of Frontiers in Neurology proposes use of “systems science” to better understand concussion diagnosis and prognosis. This is a discipline that analyzes complex problems as whole systems and integrates research findings from different disciplines. In explaining the need for a systems approach, the reviewers note one description of concussion that is uniformly recognized – that it is a highly heterogeneous phenomenon, with numerous factors interacting dynamically to influence an individual’s recovery trajectory. (This concept is highlighted in the title of one of the Concussion WebCasts made available by the American Association of Family Physicians : “If you have seen one concussion, you have seen one concussion.”) Read More
The open source journal Brain Science has just published a survey of literature demonstrating that a mild traumatic brain injury (mTBI) , otherwise known as concussion, is a complex pathophysiological process that can have a systemic effect on the body aside from solely impairing cognitive function. According to the article, “dysfunction in the autonomic nervous system (ANS) has been found to be a major factor in the symptomatology in TBI, including in mTBI” and can “induce abnormalities in organ systems throughout the body.” Read More
One of the most common symptoms following TBI is photophobia, an intense intolerance to light that can cause significant discomfort, interfere with activities of daily living, and contribute to post traumatic headaches. It can impact the ability to work at computer screens and in well-lit offices and can cause a great deal of fatigue for patients who try to return to usual activities. Avoiding light can be very limiting. Read More
A topic frequently addressed in this blog is the building body of evidence showing that the minority of patients who have long term, sometimes permanent, symptoms following concussion typically experience those symptoms because of injury to the brain, not to achieve some “secondary gain.” Although scientists do not have a clear understanding about why some people are more vulnerable to these injuries, we know as discussed in prior posts, that certain factors can play a role, such as genetics, prior head injuries and a history of migraines. Two recently published studies contribute to our understanding that real pathology likely underlies most persistent symptoms and that this pathology can be identified with advanced neuroimaging techniques. Read More
University of Toronto researchers have just published an important longitudinal study in the peer-reviewed Journal of Neurotrauma following patients with Post-Concussion Syndrome (PCS) based on a diagnosis of concussion in conformity with the international sport concussion criteria. This was the first longitudinal study that specifically excluded patients with contusions and hemorrhages identified by imaging (so-called “complicated” concussions), patients who tested positive on so-called “malingering” tests (the TOMM) and patients involved in litigation. Read More
In a study published in the Journal of the American Medical Association (JAMA) on December 20, 2016, Canadian researchers found that children and adolescents who returned to exercise within seven days of experiencing a concussion had nearly half the rate of persistent post-concussive symptoms a month later. This finding challenges the current cornerstone of pediatric concussion management, which is physical and cognitive rest until acute symptoms have resolved. Read More
In recent years a great deal of research has been done to identify an objective “biomarker” of concussion. As reported in this blog, some promise has been found in blood biomarkers (measuring plasma tau protein levels) and neuroimaging, such as the DTI MRI sequence. Unfortunately, these approaches are invasive and/or expensive and are not always a reliable indicator of concussion and concussion recovery. As reported in our November 27, 2016 blog post, until now, one of the most promising concussion screening tools was a series of vision tests endorsed by the Department of Defense.
Scientists at Northwestern University have now found a related, and what appears to be an even more precise and accurate tool, a measure of the brain’s electrophysiological response to sound. Read More
Department of Defense researchers endorse use of eye tests as an effective screening tool for acute mild traumatic brain injury (concussion)
In prior posts we have discussed the growing recognition that one of the signature symptoms of concussion is a subtle change in visual processing. Army researchers funded by the US Department of Defense have just published findings further supporting this understanding in the November 15, 2016 issue of the Journal of the Neurological Sciences.
In the published findings, the authors note that “mild” traumatic brain injury (mTBI) is sometimes difficult to diagnose because of the overlap of symptoms with other disorders such as PTSD. This has led to a quest for biomarkers or diagnostic tests (e.g. protein, imaging, cognitive, neurosensory.) This quest is especially significant for warfighters at risk for more severe “second-impact” concussions and whose lives and safety may be endangered by visual or cognitive compromises. Read More