After a concussion occurs, symptoms most commonly experienced are
headache, dizziness, memory problems and sleep disturbances, as well as
visual dysfunction. Such symptoms can be difficult to quantify and
follow in patients on a long-term basis.
‘Patients who sustained a concussion, followed by symptoms of visual dysfunction, experienced significantly delayed central and peripheral vision reaction times.’
Patient reports of feeling 'slower than normal' after a concussion
have been associated with visual dysfunction of the central vision
reaction times (CVRT). However, until now, little research has been done
on peripheral vision reaction times (PVRT) post-concussion.
athletes, where slowed reaction time can put them at higher risk for
injury or re-injury, monitoring reaction times in players can be a key
assessment before allowing them to return to play.
Results of a study conducted at the University of Cincinnati College
of Medicine reported that patients who sustained a concussion, followed
by symptoms of visual dysfunction, experienced significantly delayed
central and peripheral vision reaction times when compared with a
control group of patients with no history of concussion. The study is
published online this month by the Clinical Journal of Sport Medicine
"We concluded that CVRT and PVRT are both substantially slowed in
patients with post-concussion visual dysfunction with the PVRT being
disproportionately prolonged when compared with the healthy control
group," says Joe Clark, PhD, professor in the Department of Neurology
and Rehabilitation Medicine.
"Disturbances to peripheral vision can have major implications not
only on performance, but also safety, including sports-related
return-to-play decisions," says Clark. "Peripheral vision in particular
plays an important role in protecting athletes from impending impacts
because they must see and react to events in their periphery."
Similarly, peripheral vision is important in day-to-day activities
of the general population, namely balance and driving. Studies have
found that visual sensory symptoms following a concussion can actually
be useful indicators and aid in concussion management, but those studies
generally depend upon reliable baselines.
The current study suggests
that comparing central to peripheral reaction times are less dependent
upon baselines. Not requiring baselines might make the measurement of
the PVRT to CVRT ratio a very useful diagnostic method.
The pilot study used the Dynavision D2, a visual motor and
neuro-cognitive rehabilitation and sports training device used by
occupational, physical and speech therapists, neurologists, athletic
trainers, coaches and tactical professionals.
"There is a need for methods to objectively assess a patient's
concussion symptoms, in order to best aid their recovery over time.
Based on this preliminary study data on CVRT and PVRT and the ratio
between them may provide objective diagnostic data independent of
symptoms subjectively reported by the patient."