The effect of expectation and tinted overlays on reading ability in dyslexic adults

Abstract

Recently published theories suggest that scotopic sensitivity causes reading difficulty and may be remediated by use of colored overlays. This study examined two parallel and nonexclusive explanations for dyslexia treatment success using colored lenses. A sample of 132 subjects (66 dyslexic readers and 66 normal readers), 18-66 years of age, completed reading measures and computerized testing for scotopic sensitivity under two visual treatment conditions. This study first evaluated the relationship between scotopic sensitivity, colored lenses and reading ability. Twenty-eight subjects (21%) obtained scores in the scotopically sensitive range. However, the majority of these scotopically sensitive subjects were normal readers. Additionally, results indicated that scotopic sensitivity scores were not related to initial reading ability, response to colored lenses, or reading ability after treatment. The second explanation for treatment success examined the impact of the therapeutic common factor known as "expectation of improvement". Subjects were randomly assigned to either a hope group or a counterdemand group prior to the randomly assigned to either a hope group or a counterdemand group prior to the testing and treatment conditions. Results confirmed that expectation of improvement was a powerful therapeutic tool for all participants whether dyslexic or normal readers. However, the interaction of treatment group and presence of dyslexia indicated that dyslexics are more sensitive to expectation. While normal readers in the hope group improved an average of 2.5 months, dyslexics improved an average of 1.2 academic years in reading ability. All but 2 dyslexics in the hope group improved--a range of 2 months to 3 full academic years. After intervention, 40% of dyslexic subjects in the hope group no longer met criteria for dyslexia and anecdotal information is available on one subject who maintained gains at a 4 week mark. The power of the expectation factor is a unifying explanation for the pattern of recovery (improvement or cure) that has been historically reported for a variety of treatments including eye patches, drugs, behavioral therapy, and educational strategies reported in formal research, while few dyslexics improve in the general, "nonresearch" population regardless of the treatment.