Background

Light sensitivity can be a disabling symptom in posttraumatic headache (PTH). The objective of this pilot study was to characterize photophobia symptoms and visual pain thresholds in PTH compared to healthy controls (HC).

Methods

Individuals with PTH attributed to mild traumatic brain injury (mTBI) (N = 18) and HC (N = 20), aged 18–65, were prospectively assessed using the Photosensitivity Assessment Questionnaire (PAQ), State Trait Anxiety Inventory (STAI), and Beck Depression Inventory (BDI). A progressive light stimulation device was used to quantify visual pain thresholds. Visual pain thresholds were determined by the intensity of light at which subjects first noted pain. The mean of 3 trials was considered the visual pain threshold. Two sample t-test, Wilcoxon rank sum test, 2 test and Fisher exact test was used to compare the 2 groups for their demographics, clinical characteristics, and outcomes measures.

Results

There were no differences in demographics including age, gender, or race. The average time since onset of PTH was 50.7 (73.6) months. Those with PTH had 15.8 (9.2) headache days per month. BDI and STAI scores were significantly higher in PTH compared to HC. Photophobia was higher in PTH compared to HC, 0.64 (0.25) vs 0.24 (0.24), p < 0.0001. Visual pain thresholds were lower in PTH (median 50.1 lux; quartiles 15.3 to 300.0) compared to HC (median 863.5 lux; quartiles 519.9 to 4,906.5; p = 0.0002).

Conclusion

Photophobia symptoms are higher and visual pain thresholds are lower in PTH compared to HC. Light sensitivity is a well-known disabling symptom in PTH and this pilot study provides objective data through a validated photophobia scale and visual pain thresholds to characterize light sensitivity. Additional studies are needed to confirm this data, to compare acute to persistent PTH, to compare PTH to other headache disorders, and to determine if photophobia and visual pain thresholds will improve with intervention.

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