**3. Conclusion**

Autism is a diverse manifold neurodevelopmental disorder affecting many of the child's abilities. Some disabilities are core features, while others are comorbidities. The clinical picture therefore differs from one child to another. The main deficit in neurodevelopment is that of aberrant connectivity.

**25**

**Author details**

Egypt

provided the original work is properly cited.

Marwa Mahmoud Saleh\* and Aya Adel

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Phoniatric Unit, Department of Otolaryngology, Ain Shams University, Cairo,

\*Address all correspondence to: marwa.saleh7@gmail.com

*Autism: A Neurodevelopmental Disorder and a Stratum for Comorbidities*

*DOI: http://dx.doi.org/10.5772/intechopen.82496*

*Autism: A Neurodevelopmental Disorder and a Stratum for Comorbidities DOI: http://dx.doi.org/10.5772/intechopen.82496*

*Neurodevelopment and Neurodevelopmental Disorder*

demands of the environment would be disrupted [39].

sensory hyporesponsiveness, and sensory seeking.

of meaningful social relationships.

A third comorbidity commonly occurring with autism is sensory processing disorders (SPDs). Sensory processing means the brain's ability to register, organize, and make sense of the information received through one's senses. SPDs are commonly encountered with autism and have recently been included among the diagnostic criteria in DSM-5. They might even be encountered in children with other developmental disabilities and in typically developing children as well. When sensory processing is dysfunctional, the individual's ability to cope with the

Suarez [39] have drawn a hierarchical classification of SPD, dividing it into three main categories: sensory-based motor disorder (poor motor planning and/ or postural instability resulting from improper processing of information from the senses), sensory discrimination disorder (inability to perceive differences and similarities in data received from the senses which can make reading very challenging), and sensory modulation disorder (impairment in intensity and nature of behavior in response to sensory information). The latter subtype is the one commonly

encountered in autism, and it has three subcategories: sensory hyperresponsiveness,

Consequently, autistic individuals with SPD can be categorized into hyporesponsive, hyperresponsive, or sensory seekers. The hyperresponsiveness means overreaction to sensations that are typically harmless or not even perceived by others. Inappropriate behavior outbursts may be triggered by feeling textures on the skin (clothes and food), movement activities (swinging), or hearing sudden noises (doorbells). They are overcautious and resist changes in daily routine. The hyporesponsiveness requires intense sensory input to attract the attention of the child as sustained loud sound. Symptoms include not responding to name, or even to painful stimuli. Sensory seeking is characterized by excessive drive for certain sensory stimuli, as putting things in the mouth or touching people to the point of annoying them. Sensory seeking may be injurious or disrupting to the development

The proposed division of sensory modulation disorder into distinct subcategories serves theoretical understanding of the problem. Clinically, however, the autistic children show a mixture of symptoms that belong to more than one subcategory. They might be annoyed by ordinary sounds to the degree that they cover their ears, and they might be attracted to very fine sounds as the sound of turning of a page, or they might ignore a very loud sound [40]. Some researchers have reported positive associations between hyporeactivity and social communication symptom severity, whereas others have found that child hyperreactivity is likely to negatively affect

Questions have arisen regarding the relation of restricted repetitive behavior and sensory processing disorders (SPDs) in autism. Gabriels et al. [42] have suggested the presence of a subgroup with frequent restricted repetitive behavior and multiple abnormal sensory responses due to significant relationship between both. Hyper- or hyporeactivity to sensory stimuli have actually been included in DSM-5 as one of the forms that exist under the title of "Restricted Repetitive patterns of

Autism is a diverse manifold neurodevelopmental disorder affecting many of the child's abilities. Some disabilities are core features, while others are comorbidities. The clinical picture therefore differs from one child to another. The main deficit in

family life and social adaptive behaviors of school-age children [41].

neurodevelopment is that of aberrant connectivity.

**24**

Behavior."

**3. Conclusion**
