Sensory Processing Disorder (SPD), exists when sensory signals are either not detected or don’t get organized into appropriate responses. Pioneering occupational therapist, educational psychologist, and neuroscientist A. Jean Ayres, PhD, likened SPD to a neurological “traffic jam” that prevents certain parts of the brain from receiving the information needed to interpret sensory information correctly. A person with SPD finds it difficult to process and act upon information received through the senses, which creates challenges in performing countless everyday tasks. Motor clumsiness, behavioral problems, anxiety, depression, school failure, and many other problems may impact those who do not have effective treatment.
One study (Ahn, Miller, Milberger, McIntosh, 2004) shows that at least 1 in 20 children’s daily life is affected by SPD. Another research study by Alice Carter and colleagues who are members of the Sensory Processing Disorder Scientific Work Group (Ben-Sasson, Carter, Briggs-Gowen, 2009) suggests that 1 in every 6 children experiences sensory symptoms that may be significant enough to affect aspects of everyday life functions.
The causes of Sensory Processing Disorder presents a pressing question for every parent of a child with SPD. Many worry that they are somehow to blame for their child’s sensory issues.
Parents ask, “Is it something I did?”
Preliminary research suggests that SPD is often inherited. If so, the causes of SPD are coded into the child’s genetic material. Prenatal and birth complications have also been implicated, and environmental factors may be involved. For example, children who are adopted often experience SPD, due perhaps to restrictions in their early lives or poor prenatal care. Birth risk factors may also cause SPD (low birth weight, prematurity, etc).
Of course, as with any developmental and/or behavioral disorder, the causes of SPD are likely to be the result of factors that are both genetic and environmental. Only with more research will it be possible to identify the role of each.
A preliminary summary of research into causation and prevalence is contained in Sensational Kids: Hope and Help for Children With Sensory Processing Disorder (New York: Perigee, 2014, 2nd edition).
Children at risk for having or developing SPD are those who:
1. Have Autism, Aspergers, PDD, or other spectrum disorders (which are neurologically based too).
2. Have been institutionalized or understimulated during critical periods of neurological development.
3. Have been tube fed for extended periods of time (due to decreased oral stimulation and proper oral motor development).
4. Have Fragile X Syndrome, Fetal Alcohol Syndrome, Down Syndrome, ADD/ADHD and other developmental delays and neurological disorders.
5. Were drug addicted during fetal development.
6. Have relatives with SPD, especially parents or siblings.
7. Do not receive proper, or enough, stimulation to all senses during development.
8. Had extended hospital stays, especially in the first year.
9. Have been exposed to a variety of environmental toxins.
10. Have food allergies.
11. Those with mental health issues (although the chicken/egg theory can be argued here), as it increasingly becomes apparent in adults.
12. Are gifted.
There are also individuals who can not identify a cause by any of the above, and for unknown reasons develop (or are “born with”) SPD as well.