Suppression of experimental autoimmune encephalomyelitis by 300-315nm ultraviolet light.

Multiple sclerosis (MS) is a chronic debilitating disease, with lowest incidence in equatorial regions and highest incidence in temperate regions. This relationship is believed to be related to sunlight or UV light exposure. Recent evidence with experimental autoimmune encephalomyelitis (EAE), an animal model of MS, established that this suppression is not mediated by vitamin D production. UV is comprised of three general wave bands: UVC (100-280nm), UVB (280-320nm) and UVA (320-400nm). In the present study we used four lamps that emit different wavelengths of UV: (1) broad band UVB (BB-UVB: 280-320nm); (2) narrow band UVB (NB-UVB: 300-315nm); (3) broad band UVA (BB-UVA: 300-400nm); and (4) long wavelength UVA (UVA-1: 340-400nm). The effect of these light sources was studied in vitamin D-sufficient C57BL/6 mice. The NB-UVB largely accounted for the suppression and delay of onset of EAE by BB-UVB. In contrast, UVA-1 failed to suppress EAE severity at low (∼2.5KJ/m(2)), medium (∼5.0KJ/m(2)) and high (∼10.0KJ/m(2)) doses. Serum calcium and 25-(OH)D3 levels were unchanged after both NB-UVB and UVA-1 treatments. The results demonstrate that NB-UVB (300-315nm) is largely responsible for light-induced suppression of EAE and its effect is not via production of vitamin D.

Reduced Gain and Shortened Time Constant of Vestibular Velocity Storage as a Source of Balance and Movement Sensitivities in Gravitational Insecurity.

Gravitational insecurity (GrI) involves lifetime movement and balance concerns whose pathophysiological origins are unclear. We tested whether balance symptoms in mild GrI might involve anomalies in vestibular velocity storage (VVS), a brainstem/cerebellar circuit that amplifies gain and prolongs the persistence of weak vestibular signals from small/slow head movements. A Provisional Gravitational Insecurity Index (PGrI) was developed, evaluated for psychometrics/demographics, and used to identify otherwise healthy adults with life-long balance challenges as well as sex, age, and ethnicity-matched comparison adults without such challenges. Balance confidence, sensory hypersensitivities, spatial orientation, anxiety, and hearing loss were self-reported. Standing balance under visual/proprioceptive restrictions and perrotary vestibulo-ocular nystagmus were evaluated. The PGrI showed approximated test-retest reliability and convergent and discriminant validity. When only vestibular input was available, mild GrI participants on a tilting platform used effortful hip strategies for balance significantly more than did comparison participants. Rotation testing revealed that mild GrI participants had significantly less low frequency gain and shortened VVS persistence. Combined, these two parameters correlated significantly with PGrI. The PGrI also correlated with problematic spatial orientation, but surprisingly, not to anxiety. Balance/movement issues in GrI are likely due to VVS deficiencies. Additional mechanisms may account for other GrI symptoms. Better understanding of GrI's pathophysiological basis will be useful in informing the larger health-provider community about this condition.

On-road driving test performance in veterans: Effects of age, clinical diagnosis and cognitive measures.

INTRODUCTION: Veterans are at heightened risk of being in a motor-vehicle crash and many fail on-road driving evaluations, particularly as they age. This may be due in part to the high prevalence of age-associated conditions impacting cognition in this population, including neurodegenerative diseases (e.g., Alzheimer's Disease) and acquired neurological conditions (e.g., cerebrovascular accident). However, understanding of the impact of referral diagnosis, age and cognition on Veterans' on-road driving performance is limited. METHODS: 109 Veterans were referred for a driving evaluation (mean age = 72.0, SD = 11.5) at a driving assessment clinic at the Minneapolis Veterans Affairs Healthcare System. Of the 109 Veterans enrolled, 44 were referred due to a neurodegenerative disease, 37 due to an acquired neurological condition, and 28 due to a non-neurological condition (e.g., vision loss). Veterans completed collection of health history information and administration of cognitive tests assessing visual attention, processing speed, and executive functioning, as well as a standardized, on-road driving evaluation. RESULTS: A total of 17.9% of Veterans failed the on-road evaluation. Clinical diagnostic group was not associated with failure rate. Age was not associated with failure rates in the full sample or within diagnostic groups. After controlling for age, poorer processing speed and selective/divided attention were associated with higher failure rates in the full sample. No cognitive tests were associated with failure rates within diagnostic groups. CONCLUSION: Referral diagnosis and age alone are not reliable predictors of Veterans' driving performance. Cognitive performance, specifically speed of processing and attention, may be helpful in screening Veterans' driving safety. Practical Applications: Clinicians tasked with assessing Veterans' driving safety should take into account cognitive performance, particularly processing speed and attention, when making decisions regarding driving safety. Age and referral diagnosis, while helpful information, are insufficient to predict outcomes on driving evaluations.