title: Influence of multiple sclerosis, age and degree of disability, in the position of the contrast sensitivity curve peak.
abstract: BACKGROUND
  Contrast sensitivity (CS) function is one of the most important tests available for evaluating visual impairment. Multiple sclerosis (MS) can produce highly selective losses in visual function and psychophysical studies have demonstrated CS deficits for some spatial frequencies.
  
  
  OBJECTIVE
  This work studies the differences in CS between a group of controls and a group of MS patients, focusing on the location of the maximum sensitivity peak, shape of the curve, and determination of the most affected spatial frequencies.
  
  
  METHODS
  Using a sinusoidal stimulus the authors assessed CS function in 28 subjects with definitive relapsing remitting MS, and in 50 controls with acuities of 20/25 or better. The peaks of the CS curves were studied by fitting third degree polynomials to individual sets of data.
  
  
  RESULTS
  Compared with the control group, the CS function curve for MS subjects showed more deficits in extreme points (low- and high-spatial frequencies). Our results display significant CS losses, at the high-frequencies band level, in the beginning of the disease. When the disease progresses and the disabilities appear, there are greater losses at the low-frequencies band level. In average, the CS curve peaks for the MS group were shifted in relation to the control group.
  
  
  CONCLUSIONS
  CS losses in the MS group suggest an association with ageing and disability level in the expanded disability status scale. The position of the CS function peak is influenced by MS, age, and degree of disability.
authors.affiliation: Department of Physics, University of Beira Interior, Remote Sensing Unit, Guarda, Portugal.
authors.forename: A F
authors.initials: AF
authors.lastname: Nunes
authors.forename: P M L
authors.initials: PM
authors.lastname: Monteiro
authors.forename: M
authors.initials: M
authors.lastname: Vaz Pato
mesh_terms: D000328:Adult; D000367:Age Factors; D015350:Contrast Sensitivity / Q000502:physiology*; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000150:complications* / Q000503:physiopathology / Q000534:rehabilitation; D010775:Photic Stimulation; D011379:Prognosis; D014786:Vision Disorders / Q000209:etiology / Q000503:physiopathology* / Q000534:rehabilitation; D014792:Visual Acuity