Greenlight may reduce intensity and frequency of headache in migraine: Study
USA: Exposure to green light therapy can significantly reduce the number of headaches per month and pain intensity in patients with migraine, finds a recent study in the journal Cephalalgia.
Pharmacological treatment can be ineffective for some migraine patients. Laurent F Martin, University of Arizona, Tucson, AZ, USA, and colleagues have previously demonstrated that exposure to green light resulted in the reversal of thermal and mechanical hypersensitivity and antinociception in rodent pain models. The researchers, therefore, evaluated green light as a potential therapy in patients with episodic or chronic migraine, given the safety of green light-emitting diodes.
For this purpose, the researchers recruited 29 patients, out of which 7 had episodic migraine and 22 had chronic migraine. They used one-way cross-over design consisting of exposure for 1–2 hours daily to white light emitting diodes for 10 weeks, followed by a 2-week washout period followed by exposure for 1–2 hours daily to green light emitting diodes for 10 weeks. Patients were allowed to continue current therapies and to initiate new treatments as directed by their physicians.
The primary outcome measure was the number of headache days per month. Secondary outcome measures included patient-reported changes in the intensity and frequency of the headaches over a two-week period and other quality of life measures including the ability to fall and stay asleep, and ability to perform work. Changes in pain medications were obtained to assess potential reduction.
Key findings of the study include:
- When seven episodic migraine and 22 chronic migraine patients were analyzed as separate cohorts, white light emitting diodes produced no significant change in headache days in either episodic migraine or chronic migraine patients.
- Combining data from the episodic migraine and chronic migraine groups showed that white light emitting diodes produced a small, but statistically significant reduction in headache days from (days ± SEM) 18.2 ± 1.8 to 16.5 ± 2.01 days.
- Green light emitting diodes resulted in a significant decrease in headache days from 7.9 ± 1.6 to 2.4 ± 1.1 and from 22.3 ± 1.2 to 9.4 ± 1.6 in episodic migraine and chronic migraine patients, respectively.
- While some improvement in secondary outcomes was observed with white light emitting diodes, more secondary outcomes with significantly greater magnitude including assessments of quality of life, Short-Form McGill Pain Questionnaire, Headache Impact Test-6, and Five-level version of the EuroQol five-dimensional survey without reported side effects were observed with green light emitting diodes.
- Conclusions regarding pain medications reduction with green light emitting diode exposure were not possible.
- No side effects of light therapy were reported. None of the patients in the study reported initiation of new therapies.
"Green light-emitting diodes significantly reduced the number of headache days in people with episodic migraine or chronic migraine," wrote the authors. "Additionally, green light-emitting diodes significantly improved multiple secondary outcome measures including quality of life and intensity and duration of the headache attacks."
"As no adverse events were reported, green light-emitting diodes may provide a treatment option for those patients who prefer non-pharmacological therapies or may be considered in complementing other treatment strategies," they concluded.
The study titled, "Evaluation of green light exposure on headache frequency and quality of life in migraine patients: A preliminary one-way cross-over clinical trial," is published in the journal Cephalalgia.