So for those that do not know, SPD, or Sensory Processing Disorder, is a condition in which there is trouble interpreting sensory input; difficulty processing information from the senses that can cause irritability, anxiety, pain, depression, mood swings, exhaustion, heightened sensitivity, fight or flight. One may have issue with one or multiple senses. As I have been finding, it can be called different things, such as Sensory Integration (SI), Sensory Integration Dysfunction, Sensory Defensive, or Highly Sensitive Person (HSP). Not everyone affected experiences the same symptoms, one may be hypersensitive, under responsive, avoiders, or seekers. It is usually caught early when a baby or child is a very picky eater, is fussy, covers ears to drown out noises, withdraws, has mood swings, reacts unusually to pain.
Here are several websites with further info and symptoms checklists: