Hyperactivity, Impulsivity, and Sensory Processing PDF Print E-mail

In the previous article, we described our experience of sensory processing disorders or dysfunction of sensory integration in a group of 50 consecutive children seen in a general learning disorders clinic.[i] We reported that 52% of these children (70% of those under 10) had problems with sensory processing severe enough to contribute to their learning difficulties. We also reported that children with sensory processing were far more likely than those without to show evidence of hyperactivity or impulsivity on exam. During our exam, 50% of the children with sensory processing disorders engaged in hyperactive behaviors such as running around the exam room, jumping and crashing into things, or extreme fidgeting, while only 9% of the children without sensory processing problems showed such behaviors. We observed impulsive behaviors, such as grabbing items without asking, beginning test questions without waiting, and answering questions in an unplanned manner, in 31% of children with sensory processing disorders but only 8% of children without.

We pointed out in that article that these findings raise important questions regarding the relationship of sensory processing disorders and Attention Deficit Hyperactivity Disorder (ADHD), whose cardinal manifestations are hyperactivity, impulsivity, and distractibility or attentional impairment. In this article, we would like to address these questions in further detail, drawing additional information from our review of 50 children. We would like to state at the start of this discussion that this informal review of fifty cases clearly does not constitute definitive proof of any particular hypotheses. However, we do feel that our experience is highly suggestive and has important implications for parents, teachers, and clinicians who care for children with sensory processing disorders regarding the need for careful screening and evaluation of these children. With this caution in mind we would like to turn to the data.

In our group of 50 children, 18 showed evidence of hyperactivity (8), impulsivity (3, or both (7) on exam. Perhaps the most remarkable thing about this group of children is the high prevalence--indeed the universality--of significant sensory or neurologic impairments. Table 1 summarizes the categories of sensory and neurologic impairments found in these children.
Three of these children (17%) had previously been diagnosed with ADHD. Each of these 3 was on stimulant medication for this disorder. Based on our assessment, three additional children from this group were strongly suspected of having ADHD and were referred back to their primary care providers for consideration of a trial of stimulant medications.
Fifteen of the18 children (83%) were diagnosed with DSI. Importantly, this subgroup of 15 children included all 7 who showed both impulsivity and hyperactivity on exam, all three who had previously been diagnosed with ADHD, and all 3 of the previously undiagnosed children whom we suspected of having ADHD.

Twelve of the 18 children (67%) had significant visual abnormalities. These abnormalities included problems with tracking, convergence, binocularity, astigmatism, and acuity. Most of these problems were previously unsuspected, and each of them was significant enough to impact learning performance.

Twelve of these 18 children (67%) also showed difficulties of auditory functioning consistent with the diagnosis of central auditory processing deficit (CAPD). During testing, these children repeatedly demonstrated behaviors characteristic of children with CAPD including prolonged auditory latency, frequent mishearing, hyperacusis, auditory distractibility, impaired inference and comprehension when listening compared with reading, and marked discrepancy between auditory short term memory (their ability to repeat back like a tape recorder) and auditory comprehension. Many of these children have subsequently had the diagnosis of CAPD confirmed by audiometric testing. Two additional children were found to have combined disorders of expressive and receptive language, and in addition to speech difficulties displayed many of the symptoms similar to the children with CAPD.

Evidence of significant neurological dysfunction (in addition to those related directly to sensory processing disorders and ADHD) was also found in 12 (67%) of the 18 children. Four had mild hemiparesis and one had monoparesis. Two had evidence of significant bihemispheric injuries. Two had combined receptive and expressive language difficulties. One was diagnosed with a seizure disorder, one had Tourette's syndrome, one had a significant sensory neuropathy, and one was suffering from fetal alcohol syndrome. Again, most of these abnormalities had been previously undiagnosed.

In total, all but one of the 18 children displayed either significant visual or auditory sensory difficulties, and the excluded child showed deficits from fetal alcohol syndrome so diffuse that adequate sensory exam was difficult. Each of the children with DSI had either a visual or auditory sensory disorder, and 7 of these 15 children had both.

These findings raise several of important points regarding the evaluation and management of children with hyperactivity and impulsivity. The first and most important of these points is the absolute necessity of recognizing how frequently such children are suffering from sensory and neurological impairments other than primary attentional disorders. In our sample of 18 children, impairments of this kind were found in every child, and most had significant impairments in several systems.

It is, of course, possible that the children in our sample are not entirely representative of children with hyperactivity and impulsivity in the general population. Eight of the 18 children (44%) have been placed in alternative learning environments as a result of their disabilities (see Table 2). Still, we have several reasons to suspect that they are representative enough to be revealing. First, many of our children were self-referred, and we were the first evaluators for some. And while we do have a specialty clinic and see many patients by referral, we are a community-based practice rather than an academic one, and as such are a first line of referral for children having difficulties. Second, ten (56%) of the children in our sample are enrolled in regular classes in public elementary or large private schools, and as such are probably a reasonable sample of children in typical educational settings. Third, others have previously noted high frequencies of neurologic impairments in children diagnosed with ADHD[ii]. In one particularly revealing article an ophthalmologist from the University of California at San Diego documented visual tracking abnormalities in nearly half of a sample of randomly selected children with ADHD[iii].

Our findings also suggest several important points about sensory processing disorders. First, they highlight the fact that sensory processing disorders are frequently seen as a secondary manifestation of neurologic impairment, and they stress the importance of looking for evidence of specific sensory impairments in children with sensory behaviors. When brain development is impaired, either through injury or through the failure of primary sensory systems to promote appropriate growth of central processing centers, the brain attempts to compensate for this impairment by remodeling or rewiring.[iv] Compensatory rewiring can result in improved function in some respects, but it can also result in function that is poorly regulated if the new connections lack the appropriate balance of stimulatory and inhibitory influences. W
hen imbalance occurs in areas that regulate sensory or sensory motor functions, sensory processing dysfunction results, with its classic manifestations of hyper and hyposensitivities and their resulting sensory avoidant and sensory seeking behaviors.[v] In children with sensory processing disorders, behaviors often labeled hyperactive appear to be unreflective attempts to maintain sufficient arousal of their understimulated alertness centers to allow their brains to function in a useful way. That's why, in our experience, "hyperactive" behaviors in children with sensory processing disorders frequently sharpen their attention and improve focus on our testing, rather than impair their attention and performance.

This process of impairment and rewiring also helps explain the frequent presence of distractibility in children with sensory processing disorders and/or sensory impairments. A clear example of the way such rewiring results in secondary distractibility is seen in persons who are deaf. When a child is born deaf, cerebral cortical areas usually reserved for auditory processing are recruited for other functions such as vision[vi]. Visual sensitivity may be somewhat improved in the central visual fields, but only at the expense of heightened visual distractibility at the periphery. This is why hearing-impaired readers often become paralyzed when trying to read visually busy books and worksheets. This pattern of one sensory system compensating for the deficiencies of another can also be observed among the blind.[vii]

The high rates of impulsivity, hyperactivity, and distractibility seen in children with sensory processing disorders can often make it difficult to determine in particular children whether these behaviors are simply manifestations of sensory dysfunction or whether they are signs of a primary attentional disorder like ADHD. In our experience the purely behavioral criteria for ADHD listed in the DSM-IV are not particularly useful in making these distinction. Nearly all of the children in our sample with hyperactivity and/or impulsivity would meet these criteria, yet we do not feel most of these children show sufficient evidence of a primary attentional disorder to merit a diagnosis of ADHD. Although there are as yet no generally accepted criteria for distinguishing between these conditions, and though in our sample 33% of children were diagnosed with both, we have found two criteria useful in distinguishing children whose hyperactivity appears to be due to sensory processing disorders and those in whom it appears to result from primary attentional disorders. First, we believe the diagnosis of ADHD is best suited to children who show generalized attentional impairment in all areas of testing, rather than those who have selective attentional problems only with tasks that stress struggling visual or auditory systems. Second, we find the ADHD label better suited for those children whose self-stimulatory and hyperactive behaviors produce a worsening of performance instead of an improvement.

Just the other day we had a young patient who exceeded age norms on many portions of our tests while working non-stop on the most elaborate piece of theraputty pizza (complete with pepperoni and
mushrooms) ever made. Hyperactive? Yes. Sensory seeking? Yes. Attentional impairment? Not that we can detect.
What's the bottom line? In children with impulsivity and hyperactivity, the answer should never simply be a straight line to stimulants. It is crucial to evaluate such children for disorders of sensory integration and other visual, auditory, or somatosensory impairments.

About the Authors: Brock and Fernette Eide are physicians and consultants to a wide range of parent, teacher, and clinical professional groups seeking more information about brain-based difficulties and their solutions. Together they have authored more than 50 articles and they speak internationally for keynote lectures, seminars, workshops, and small groups. The Eides can be contacted through their website at: www.neurolearning.com or by email at: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .