A concussion is a traumatic brain injury that alters the way your brain functions. Effects are usually temporary but can include headaches and problems with concentration, memory, balance and coordination. Although concussions usually are caused by a blow to the head, they can also occur when the head and upper body are violently shaken. These injuries can cause a loss of consciousness, but most concussions do not. Because of this, some people have concussions and don’t realize it. Concussions are common, particularly if you play a contact sport, such as football. But every concussion injures your brain to some extent. This injury needs time and rest to heal properly. Most concussive traumatic brain injuries are mild, and people usually recover fully. The signs and symptoms of a concussion can be subtle and may not be immediately apparent. Symptoms can last for days, weeks or even longer. Common symptoms after a concussive traumatic brain injury are headaches, loss of memory (amnesia) and confusion. The amnesia, which may or may not follow a loss of consciousness, usually involves the loss of memory of the event that caused the concussion. The post-concussion syndrome is a complex disorder in which various symptoms such as headaches and dizziness pain can last for weeks and sometimes months after the injury that caused the concussion. A concussion is a mild traumatic brain injury, usually following a blow to the head.
Loss of consciousness is not necessary for a diagnosis of concussion or post-concussion syndrome. In fact, the risk of post-concussion syndrome brain does not appear to be associated with the severity of the initial injury. In most people, symptoms of post-concussion syndrome occur in seven to ten days after the blow and may disappear within three months, but may also persist for a year or more.
Reduced cognitive abilities with visual activities
Visual perceptual deficits can be caused by concussions and have dramatic effects on school and even athletic success. Speed of visual processing and visual reaction time can be reduced. Processing speed may slow in an athlete both on and off the field. The speed with which an athlete processes visual information affects many aspects of competitive sport, including reading of the playing field, the judgment of the speed of a moving ball or puck, and judgment the speed of the other players in the field.
Post-traumatic visual syndrome and midline shift syndrome
Following a neurological event such as a traumatic brain injury, cerebrovascular accident, multiple sclerosis, cerebral palsy, etc., it has been noted by clinicians that persons frequently will report visual problems such as seeing objects appearing to move that are known to be stationary; seeing words in print run together; and experiencing intermittent blurring. More interesting symptoms are sometimes reported, such as attempting to walk on a floor that appears tilted and having significant difficulties with balance and spatial orientation when in crowded moving environments. These types of symptoms are not uncommon. Frequently, persons reporting these symptoms to eye care professionals (optometrists and ophthalmologists) have been told that their problems are not in their eyes and that their eyes appear to be healthy. What is often overlooked is dysfunction of the visual process causing one of two syndromes: Post Trauma Vision Syndrome (PTVS) and/or Visual Midline Shift Syndrome (VMSS). Recent research has documented PTVS utilizing Visual Evoked Potentials (VEP). This documentation concludes that the ambient visual process frequently becomes dysfunctional after a neurological event such as a TBI or CVA. Persons can often have visual symptoms that are related to dysfunction between one of two visual processes: ambient process and focal process. These two systems are responsible for the ability to organize ourselves in space for balance and movement, as well as to focalize on detail such as looking at a traffic light.
Post Trauma Vision Syndrome results when there is dysfunction between the ambient and focal process causing the person to over emphasize the details. Essentially individuals with PTVS begin to look at paragraphs of print almost as isolated letters on a page and have great difficulty organizing their reading ability. It has been found that the use of prisms and binasal occlusion can effectively demonstrate functional improvement, while also being documented on brain wave studies by increasing the amplitude (this is like turning up the volume on your radio). Visual Midline Shift Syndrome also results from dysfunction of the ambient visual process. It is caused by distortions of the spatial system causing the individual to misperceive their position in their spatial environment. This causes a shift in their concept of their perceived visual midline. This will frequently cause the person to lean to one side, forward and/or backward. It frequently can occur in conjunction with individuals that have had a hemiparesis (paralysis to one side following a TBI or CVA). The shifting concept of visual midline actually reinforces the paralysis, by using specially designed yoked prisms that can be prescribed, the midline is shifted to a more centered position thereby enabling individuals to frequently begin weight bearing on their affected side. This works very effectively in conjunction with physical and occupational therapy attempting to rehabilitate weight bearing for ambulation.
The symptoms of the syndrome shift of midline visual may include:
- dizziness or nausea
- spatial disorientation
- always heading towards the right or left along a corridor
- locomotion or posture problems as to lean back on your heels, forward or to one side when walking, either standing or sitting in a chair
- perception of uneven pavement (or having a sloping side or the other)
- neuromotor difficulties associated with balance, coordination and posture
Fortunately, many vision problems after a concussion can be resolved with rest and by allowing the brain to heal. But there are still many problems that can linger even after years, especially regarding spatial localization. Vision therapy, also called neuro-optometric rehabilitation, can be very effective in cases where visual symptoms persist, even when other symptoms such as dizziness or balance problems are solved.
Reading problems and concussion Reading deficits can come from various problems after stroke or injury or a blow to the head. It is crucial that the type of reading problem is diagnosed. Problems can occur individually or as part of a constellation of related problems PTVS. The treatment of PTVS by various neuro-optometric rehabilitation interventions can solve many of the problems. In the next article, we will continue discussing visual problems and concussions.
Source : Lagacé JP. Les commotions cérébrales et la vision – généralités. Revue L’Optométriste – Volume 37 No 2, Mars-avril 2015.