Irlen and The Brain
The following research papers highlight the impact that Irlen Syndrome has on brain function and anatomy.
The most current research on Irlen Syndrome and the use of color utilizes advanced brain-mapping technology to show actual changes and normalization of brain functioning that is not achieved through ophthalmological treatments (plain lenses, prisms, or vision therapy). Researchers have utilized functional magnetic resonance imaging (fMRI), visual evoked responses (VER), and single photon emission computed tomography (SPECT) scans to objectively document the profound effects of visual sensory overload on the brain and the normalization of brain activity when individually-prescribed, precision-tinted colored filters are worn.
A Magnetoencephalographic Investigation of Visual Information Processing in Irlen’s Scotopic Sensitivity Syndrome
by Jeffrey Lewine, Ph.D., John Davis, Ph.D., Sherri Provencal, M.A., James Edgar, M.A., and William Orrison, Jr., M.D.
Lewine et al. (1997) utilized magnetoencephalography (MEG) to characterize visual responses in conditions with and without lenses. In all cases, the evoked magnetic signal reflected a complicated pattern of bilateral activation of multiple cortical generators. A major difference in with and without lens conditions was seen between 170 and 200 msec post-stimulus. The data suggest that the colored Irlen lenses provide for normalization and crystallization of visual information processing in individuals with Irlen Syndrome.
Visual Revoked Responses: Yellen-Schweller Effect
by Drew Yellen
Yellen and Schweller (2009) utilized state-of-the-art Visual Evoked Responses (VER), a portion of their comprehensive neuroelectrical evaluation of patients called the DESA®, and discovered that individuals with Irlen Syndrome have early hyper reactivity to visual stimuli somewhere between 30-60 milliseconds, and it is 3-9 standard deviations above normal (the Yellen-Schweller Effect). Irlen Spectral Filters reduce the standard deviation abnormalities of the Yellen-Schweller Effect, lessening of the delay of the brain coming back “online” and allowing it to clear sooner.
Toward an Authentic Diagnostic Impression Using Clinical Composites and Functional Brain Imaging for an Improved Understanding of Irlen Syndrome
by Robert Dobrin, M.D., F.A.A.P
Light and the Brain
Brain in the News Newsletter by Daniel G. Amen M.D.
In one study by Amen and colleagues, comparing the brains of 42 people with Irlen syndrome to 200 age-matched individuals without any evidence of Irlen syndrome, SPECT scans showed increased activity in the brain’s emotional and visual processing centers and decreased activity in the cerebellum (an area that helps to integrate coordination and new information).
A Functional Neuroimaging Case Study of Meares-Irlen Syndrome/Visual Stress (MISViS)
Chouinard, B.D., Zhou, C.I., Hrybouski, S., Kim, E.S., Cummine, J. (2012). Brain Topography, 25 (3), pp. 293-307. http://link.springer.com/article/10.1007%2Fs10548-011-0212-z#page-1
Chouinard et al. (2011) compared the neurological characteristics of a person with Irlen Syndrome with control subjects who were participating in a language. The descriptive results indicated that there are numerous significant differences in many areas of the brain cortex between the control subjects and the individual with Irlen Syndrome, providing evidence of a neurobiological foundation to Irlen Syndrome.
fMRI Evidence that Precision Ophthalmic Tints Reduce Cortical Hyperactivation in Migraine
Huang, J., Zong, X., Wilkins, A., Jenkins, B., Bozoki, A., Cao, Y. (2011). Cephalagia, 31(8):925-36. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3132147/
Huang et al. (2011) used fMRI to investigate differences between individuals suffering visual stress and controls in relation to migraine and to determine the effectiveness of precision-tinted colored filters for individuals suffering from visual stress. The research showed a normalization of cortical activation and spatial frequency tuning in the migraineurs by precision tinted filters that suggests a neurological basis for the therapeutic effect of these lenses in reducing visual cortical hyperactivation in migraine.
Findings in Meares-Irlen Syndrome: A Pilot Study
Kim, J. H., Seo, H. J., Ha, S. G., & Kim, S. H. (2015). Korean Journal of Ophthalmology, 29(2), 121-125. http://synapse.koreamed.org/DOIx.php?id=10.3341%2Fkjo.2015.29.2.121
Kim et al (2015) investigated patterns of functional magnetic resonance imaging (fMRI) activation during sentence reading before and after wearing color-tinted lenses. The reading speed of patients improved more than 20% while wearing the selected lenses. When compared to the before-lens session, the after-lens session identified significant regions of activation in the left middle and superior temporal gyri. No region of activation at the same threshold was found in the before-lens session as compared to the after-lens session. These results could explain the effectiveness of color-tinted lenses in patients with Meares-Irlen syndrome.