Based on new research, the SPD Foundation, led by Director Lucy Jane Miller, Ph.D., OTR, identifies three major categories of SPD:
Sensory Modulation Disorder. This includes sensory overresponsivity, sensory underresponsivity, and sensory-seeking behaviors, or combinations thereof. People with this condition can alternate from one state to the other, sometimes seeking stimulation, for example with hand flapping or spinning, and at other times retreating from stimulation by hiding or going off alone.Sensory Discrimination Disorder. This includes difficulty with accurate perception of all the five senses, plus proprioceptive awareness (knowing how much pressure to exert), vestibular awareness (knowing where you are in space), and interoceptive awareness (being aware of your bodily functions, like hunger and the need to go to the bathroom). People with sensory discrimination problems may have trouble reading because they can’t discriminate between letters, or they may have trouble identifying who is speaking to them because they can’t locate the sources of sounds.Sensory-Based Motor Disorder. This includes postural disorders and/or dyspraxia (difficulty planning and carrying out motor tasks). People with sensory motor problems may have low muscle tone, difficulty holding utensils, poor posture, trouble with balance, and low stamina.