Evidence is discussed to show that so-called L- and P-type dyslexia result from deviations in the development of hemispheric subservience in learning to read. Investigations into the validity of the L/P classification are reviewed, as are laboratory experiments on the effects of so-called hemisphere-specific stimulation (HSS). In the present field experiment, 28 L-dyslexic children (mean chronological and reading age 10.6 and 7.5 years, respectively) received HSS of the right hemisphere by the presentation of words to the fingers of the left hand, and 26 P-dyslexic children (mean chronological and reading age 9.4 and 7.2 years, respectively) received HSS of the left hemisphere by the presentation of words to the fingers of the right hand. Control L and P subjects were treated according to the discretion of the remedial teacher. The results underscore the findings of previous laboratory experiments in that (a) HSS-treated L-dyslexics, relative to controls, tended to show larger improvement of accuracy in text reading; and (b) HSS-treated P-dyslexics, relative to controls, showed larger improvement of fluency in word reading.
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