Critical flicker frequency and related symptoms in mild traumatic brain injury.
OBJECTIVE
To determine whether critical flicker frequency (CFF) thresholds are abnormal in individuals with mild traumatic brain injury (TBI) and, if so, if they are correlated with the degree of reported motion and light sensitivity.


METHODS
The foveal CFF threshold was assessed in individuals with mild TBI (n = 18) having varying degrees of reported light and motion sensitivity. Mean CFF values were obtained using the ascending and descending psychophysical method of limits with binocular viewing at 40 cm. A 7-item, rating-scale questionnaire was used to assess the degree of light and motion sensitivity. These parameters were also assessed in a large visually-normal, non-TBI cohort.


RESULTS
CFF in the mild TBI group was not significantly different across age groups from the visually-normal, non-TBI cohort. However, mean CFF among the mild TBI subjects was significantly higher for the 'light sensitive' and 'motion sensitive' sub-groups when compared to the 'not light sensitive' and 'not motion sensitive' sub-groups. The majority of TBI subjects manifested both light and motion sensitivity.


CONCLUSIONS
CFF was found to be related to the reported degree of light and motion sensitivity in individuals with mild TBI. Neurological disinhibition as a result of brain injury may be causal of the subjective hypersensitivity to light and motion in the presence of normal CFF.
Chang
Tina Ting-Li
TT
Department of Clinical Sciences, SUNY/State College of Optometry, Raymond J. Greenwald Rehabilitation Centre, New York, NY 10036, USA.
Ciuffreda
Kenneth Joseph
KJ
Kapoor
Neera
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001930:Brain Injuries / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D005425:Flicker Fusion / Q000502:physiology*; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D009038:Motion; D009039:Motion Perception / Q000502:physiology; D010775:Photic Stimulation; D011795:Surveys and Questionnaires