Neurocognitive Deficits in Attention Deficit/Hyperactive Disorder (ADHD): Role of Sensory Processing, Visual Perception and Attention

Abstract

Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most common neurodevelopmental disorders characterized by symptoms of inattention and/or hyperactivity and impulsivity, and it affects mostly children and adolescents by causing significant impairment in their development and daily functioning. ADHD is associated with various neurobiological abnormalities and deficits, and this review article examines the current research evidence on the role of three neurocognitive domains in ADHD, namely sensory processing, visual perception and attention. Atypical sensory processing in terms of increased or reduced neural thresholds for sensory modulation can explain the distinct symptoms of the various ADHD subtypes. In visual perception, structural and functional deficits in visual processing and perception can account for the vision related problems commonly found in ADHD. Finally, deficits in selective and sustained attention observed in ADHD can indicate underlying dysfunctions in other bottom-up and top-down processes. The interaction of sensory processing, visual perception and attention has also been discussed alongside other neurobiological processes and mechanisms implicated in ADHD. Although evidence of the role of these three neurocognitive domains has significant clinical implications, the wide range of experiences and symptom manifestations in ADHD warrants further research of these and other neurocognitive and neurobiological mechanisms, as well as reconsideration of current ADHD diagnostic protocols. The article highlights the need and further scope of better understanding the psychosocial, cognitive and biological underpinnings and mechanisms of ADHD, in order to formulate more effective diagnostic and treatment approaches.