Congenital dyslexia syndrome (developmental dyslexia of critchley; congenital word blindness of hermann; primary dyslexia; dyslexia syndrome; minimal brain dysfunction syndrome; attention deficit disorder; congenital word blindness)    279

General: Primary reading disability in children with an average or above-average intelligence; male preponderance; dysfunction of the dominating parietotemporal lobe; Levinson postulates a primary cerebellar-vestibular (inner ear) dysfunction underlying this syndrome resulting in a secondary scrambled sensory input and motor output.

Ocular: No obvious connection seems to exist between coordination of ocular functions and dyslexia, although associated ocular findings may exist in reading problems (e.g., abnormal optokinetic nystagmus, metamorphopsia, defective color vision, convergence insufficiency, muscle imbalance, refractive errors); low accommodative converge/accommodation associated with decreased visual acuity and contrast sensitivity.

Clinical: General clumsiness; disorientation (time-space, right-left); behavioral changes; lack of integration of visual and auditory stimuli.

Fraunfelder FT, Roy FH. Current Ocular Therapy, 5th ed. Philadelphia: WB Saunders, 2000.

Hermann K. Congenital word-blindness: poor readers in the light of Gerstmann's syndrome. Acta Psychiatr Neurol Suppl 1956; 103:117.

Hermann K. Reading disability. Springfield, IL: Charles C. Thomas, 1959.

Levinson HN. Abnormal optokinetic and perceptual span parameters in cerebellar-vestibular dysfunction and learning disabilities or dyslexia. Percept Mot Skills 1989; 68:35-54.

Preston MS. Visual evoked responses vs normal and disabled readers. Psyche-physiology 1974; 11:452.