Cannabinoid Use in a Tertiary Headache Clinic: A Cross-Sectional Survey.

OBJECTIVE: This study seeks to determine the prevalence and nature of cannabis use in patients with headache in a tertiary headache clinic and to explore patients' empiric experience in using cannabinoids therapeutically. BACKGROUND: Many patients with headache report cannabinoid use as an effective abortive and/or preventive therapy. Mounting evidence implicates cannabinoids in pain mechanisms pertaining to migraine and other headache types. METHODS: A cross-sectional study surveyed 200 patients presenting with any headache disorder to a tertiary headache clinic in Calgary, Alberta. Descriptive analyses were applied to capture information about headache diagnoses and the frequency, doses and methods of cannabinoid delivery employed, as well as patients' perceptions of therapeutic benefit and selected negative side effects. RESULTS: Active cannabinoid users comprised 34.0% of respondents. Approximately 40% of respondents using cannabinoids engaged in very frequent use (≥300 days/year). Of cannabinoid modalities, liquid concentrates were most popular (39.2%), followed by smoked cannabis (33.3%). Patients endorsed cannabinoid use for both prevention and acute therapy of headaches, often concurrently. Sixty percent of respondents felt cannabinoids reduced headache severity, while 29.2% perceived efficacy in aborting headaches. Nearly 5% of respondents volunteered that they had encountered a serious problem such as an argument, fight, accident, or work issue as a result of their cannabis use. Approximately 35.4% of users had attempted to reduce their use. CONCLUSION: This survey shows that over one-third of patients with headache disorders in a tertiary headache clinic use cannabis as a treatment for their headaches. Of these, about 25% and 60% perceive improvements in headache frequency and severity, respectively. The results of this survey will aid neurologists and headache specialists in understanding the landscape of cannabinoid use in a more severely affected population and inform future-controlled studies of cannabinoids in headache patients.

Supernumerary phantom limbs in ICU patients with acute inflammatory demyelinating polyneuropathy.

OBJECTIVE: To explore the previously undescribed phenomenon of phantom limb generation in patients with severe acute inflammatory demyelinating polyradiculoneuropathy (AIDP). METHODS: Between April 2011 and January 2014, we encountered 3 patients with AIDP in our intensive care unit who experienced features of self-limited supernumerary phantom limbs (SPLs) during their course. RESULTS: The following case series describes the phenomenon of SPLs in AIDP. CONCLUSIONS: This report aims to raise awareness of the possibility of SPLs in the course of AIDP. The pathophysiology and management strategies for this clinical phenomenon are unknown.

Long-Duration Spaceflight Increases Depth Ambiguity of Reversible Perspective Figures.

The objective of this study was to investigate depth perception in astronauts during and after spaceflight by studying their sensitivity to reversible perspective figures in which two-dimensional images could elicit two possible depth representations. Other ambiguous figures that did not give rise to a perception of illusory depth were used as controls. Six astronauts and 14 subjects were tested in the laboratory during three sessions for evaluating the variability of their responses in normal gravity. The six astronauts were then tested during four sessions while on board the International Space Station for 5-6 months. They were finally tested immediately after return to Earth and up to one week later. The reaction time decreased throughout the sessions, thus indicating a learning effect. However, the time to first percept reversal and the number of reversals were not different in orbit and after the flight compared to before the flight. On Earth, when watching depth-ambiguous perspective figures, all subjects reported seeing one three-dimensional interpretation more often than the other, i.e. a ratio of about 70-30%. In weightlessness this asymmetry gradually disappeared and after 3 months in orbit both interpretations were seen for the same duration. These results indicate that the perception of "illusory" depth is altered in astronauts during spaceflight. This increased depth ambiguity is attributed to the lack of the gravitational reference and the eye-ground elevation for interpreting perspective depth cues.