Photophobia and allodynia in persistent post-traumatic headache are associated with higher disease burden.

OBJECTIVE: To assess photophobia and allodynia in subjects with post-traumatic headache and examine how these sensory hypersensitivities associate with clinical measures of disease burden. BACKGROUND: Post-traumatic headache is the most frequent and disabling long-term consequence of mild traumatic brain injury. There is evidence of sensory dysfunction in acute post-traumatic headache, and it is known from other headache conditions that sensory amplifications correlate with more severe disease. However, systematic studies in post-traumatic headache are surprisingly scarce. METHODS: We tested light and tactile sensitivity, along with measures of disease burden, in 30 persistent post-traumatic headache subjects and 35 controls. RESULTS: In all, 79% of post-traumatic headache subjects exhibited sensory hypersensitivity based on psychophysical assessment. Of those exhibiting hypersensitivity, 54% exhibited both light and tactile sensitivity. Finally, sensory thresholds were correlated across modalities, as well as with headache attack frequency. CONCLUSIONS: In this study, post-traumatic headache subjects with both light and tactile sensitivity had significantly higher headache frequencies and lower sensitivity thresholds to both modalities, compared to those with single or no sensory hypersensitivity. This pattern suggests that hypersensitivity across multiple modalities may be functionally synergistic, reflect a higher disease burden, and may serve as candidate markers of disease.

Low-frequency facial hemodynamic oscillations distinguish migraineurs from non-headache controls.

BACKGROUND: Surface imaging is a promising, noninvasive approach to assess regional perfusion in craniovascular disorders such as migraine. METHODS: We used optical imaging to examine differences in facial blood volume at baseline and in response to ammonia inhalation (a noxious stimulus), as well as standardized measures of cardiovascular autonomic function, in healthy, non-headache controls (n = 43) and in interictal migraine subjects (n = 22). RESULTS: Resting facial cutaneous oscillation (FCO) frequency was significantly different in migraine compared to healthy controls. Following ammonia inhalation, healthy controls showed a significant increase in resting FCO frequency, whereas this response was not significant in the migraine group. Standardized autonomic reflex parameters did not differ significantly between study groups, and facial cutaneous activity did not correlate with standardized cardiovascular autonomic reflex parameters, suggesting potentially different regulation. CONCLUSIONS: This approach to the assessment of craniofacial hemodynamic function appears to exhibit differing mechanisms from previously available techniques, and represents a promising new physiological biomarker for the study of craniofacial vascular function in migraine and potentially other craniovascular disorders.

Quantitative assessment of autonomic symptom burden in Postural tachycardia syndrome (POTS).

Postural tachycardia syndrome (PoTS) is a poorly understood disorder characterized by excessive tachycardia in the upright position. In addition, patients with PoTS often complain of non-postural symptoms, including fatigue, gastrointestinal and vasomotor fluctuations. The present study quantitatively assessed autonomic symptom burden in PoTS patients (n=32) using the COMPASS-31, compared to that of autonomic failure/neuropathy (AF/N; n=47) and asymptomatic, healthy controls (n=32). Using AIC model selection and regression analysis, we found differences in the contribution of individual COMPASS-31 domains, depending on the autonomic disorder. In PoTS, fatigue severity, orthostatic intolerance and pupillomotor symptom domains, contributed significantly to differences in COMPASS-31 scores compared to controls. In contrast, the secretomotor, gastrointestinal, bladder and vasomotor domains, contributed significantly to the AF/N model. Our results confirm an increase in autonomic symptoms across all functional domains in PoTS compared to controls, and with similar severity to AF/N, though with differing significant domain contributions. Our findings provide additional support that PoTS is indeed a syndrome of autonomic dysfunction beyond orthostatic intolerance, but also indicates the likelihood of disease-specific contributions to symptom burden, highlighting the need for application of expanded physiological assessment beyond orthostatic challenge, as well as disease-specific symptom assessment tools for use in PoTS.

Altered pupillary light response scales with disease severity in migrainous photophobia.

Background Autonomic dysfunction and light sensitivity are core features of the migraine attack. Growing evidence also suggests changes in these parameters between attacks. Though sensory and autonomic responses likely interact, they have not been studied together across the spectrum of disease in migraine. Methods We performed digital infrared pupillometry while collecting interictal photophobia thresholds (PPT) in 36 migraineurs (14 episodic; 12 chronic; 10 probable) and 24 age and sex-matched non-headache controls. Quantitative pupillary light reflexes (PLR) were assessed in a subset of subjects, allowing distinction of sympathetic vs parasympathetic pupillary function. A structured questionnaire was used to ascertain migraine diagnosis, headache severity, and affective symptoms. Results Photophobia thresholds were significantly lower in migraineurs than controls, and were lowest in chronic migraine, consistent with a disease-related gradient. Lower PPT correlated with smaller dark-adapted pupil size and larger end pupil size at PPT, which corresponded to a reduced diameter change. On PLR testing, measures of both parasympathetic constriction and sympathetic re-dilation were reduced in migraineurs with clinically severe migraine. Conclusions In summary, we show that severity of photophobia in migraine scales with disease severity, in association with shifts in pupillary light responses. These alterations suggest centrally mediated autonomic adaptations to chronic light sensitivity.