Original model
Ayress theoretical framework for what she called Sensory Integration Dysfunction was developed after six factor analytic studies of populations of children with learning disabilities, perceptual motor disabilities and normal developing children. Ayres created the following nosology based on the patterns that appeared on her factor analysis:

Dyspraxia: poor motor planning (more related to the vestibular system and proprioception)
Poor bilateral integration: inadequate use of both sides of the body simultaneously
Tactile defensiveness: negative reaction to tactile stimuli
Visual perceptual deficits: poor form and space perception and visual motor functions
Somatodyspraxia: poor motor planning (related to poor information coming from the tactile and proprioceptive systems)
Auditory-language problemsBoth visual perceptual and auditory language deficits were thought to possess a strong cognitive component and a weak relationship to underlying sensory processing deficits, so they are not considered central deficits in many models of sensory processing.In 1998, Mulligan found a similar pattern of deficits in a confirmatory factor analytic study. Quadrant model
Dunns nosology uses two criteria: response type (passive vs. active) and sensory threshold to the stimuli (low or high) creating four subtypes or quadrants:
High neurological thresholdsLow registration: high threshold with passive response. Individuals who do not pick up on sensations and therefore partake in passive behavior. Sensation seeking: high threshold and active response. Those who actively seek out a rich sensory filled environment.Low neurological thresholdSensitivity to stimuli: low threshold with passive response. Individuals who become distracted and uncomfortable when exposed to sensation but do not actively limit or avoid exposure to the sensation. Sensation avoiding: low threshold and active response.
See also
References
Further reading
Hyatt, Keith J (February 2010). "Irlen Tinted Lenses and Overlay" (PDF). MUSEC Briefings. Macquarie University Special Education Centre (22). Archived from the original (PDF) on 29 August 2017. Retrieved 22 April 2017. Wilkins, Arnold J. (2003). Reading through color: how colored filters can reduce reading difficulty, eye strain, and headaches. Chichester: John Wiley & Sons. ISBN 0-470-85116-3. OCLC 78883050.