ADHD and Auditory Processing Disorders can share a number of overlapping symptoms and behaviors in children. However, when these two disorders exist alongside each other as comorbid disorders, then the two can feed off of each other and increase the likelihood of onset of a third (or fourth) psychological or developmental disorder. A recent publication done by Ghanizadeh on ADHD and auditory processing problems found that two other disorders commonly associated with or comorbid to ADHD were more likely to appear if an auditory processing problem exists in an ADHD child. I am not going to cover the contents of the whole article, but some of the main points are listed below:
Auditory processing disorders are independent from the mechanical process of hearing (in other words, the peripheral hearing, or ability to pick up background sounds is not affected), but rather have difficulties in the screening, filtering and differentiating "important" sounds from background noise. Difficulties in this result in an impaired ability to utilize important auditory information properly. On an interesting side note, it appears that methylphenidate ( Ritalin, Concerta, Daytrana ), which is a common stimulant medication for ADHD, may actually help improve auditory processing in children. Perhaps, on an equally interesting note, the dietary mineral zinc has also been associated with information processing disorders in boys with ADHD. In an earlier blog post, we covered the topic of how supplementation with zinc could boost Ritalin's effectiveness. Therefore, it is possible that a similar underlying cause and mechanism may be at work behind ADHD and auditory processing disorders and their effective treatments, at least in this blogger's opinion.
Auditory processing problems were divided into two subcategories in the article, hypo sensitivity ( under -reacting or under -processing a sound/auditory stimulus) and hyper sensitivity ( over -reacting or over -processing a sound/auditory stimulus) to sound (an actual distinction whose existence was questioned by the author towards the end of the article). Both types can lead to similar behaviors or deficits, including difficulties screening important sounds from background noise, picking out verbal cues and selectively listening to an important voice (i.e. a parent's or teacher's voice amongst the chatter of other children), and (not surprisingly) an increased tendency towards distraction. Perhaps not surprisingly, deficits in language comprehension, utilization and verbal skills, as well as learning problems often do not fall far behind when an auditory processing disorder is present.
Although hypo- and hyper-sensitivity may be two sides of the same coin, it is interesting to note that they each appear to be correlated to different comorbid disorders common to ADHD. For example, ADHD children with comorbid auditory hyper sensitivity are (at least based on data from the study) more likely to exhibit characteristics of a separation anxiety disorder (which is characterized by apparent stress or emotional outbursts when separated from a parent or particular loved one). What is interesting about this is the fact that separation anxiety behaviors typically decrease with age, but, according to the Ghanizadeh article, hypersensitivity shows little age-related correlation.
On the other hand, auditory hypo sensitivity which occurs alongside ADHD is more likely to be associated with Oppositional Defiant Disorder (ODD), which is characterized by long-term verbal hostility, arguing, intentional disobedience, and disrespectful behaviors towards authorities. ODD can be an early symptom of later conduct disorders, which include violent and criminal behaviors. In addition, an accompanying oppositional defiant disorder can increase ADHD symptoms.
Additionally, these findings are interesting because they buck some of the trends and associations previously seen in comorbid disorders. For example, hypersensitivity in other sensory areas such as touch is frequently seen in Separation Anxiety and related disorders. This "touch" hypersensitivity is more frequently seen in girls. However, with regards to the ADHD/auditory processing/separation anxiety disorder component of the study, gender differences were not observed. This may suggest either that the gender effects on sensory hypersensitivity and its connection to separation anxiety disorders may reside more in the tactile form of sense, while auditory hypersensitivity has a much smaller gender component with regards to anxiety disorders. As a quick aside, we have looked at another form of sensory hypersensitivity recently in a post titled Does ADHD Improve your Sense of Smell?
In conclusion, we should take home two important messages from this article:
Children diagnosed with ADHD may often be missed for a comorbid diagnosis of auditory processing difficulties, a fact which is seen by the high degree of overlap between ADHD and auditory processing disorders and their shared symptoms.
Additional comorbid disorders such as anxiety disorders or defiant behaviors may actually provide clues that an underlying sensory processing disorder (such as an auditory processing difficulty) is present. Of course there are numerous potential causes to any of these accompanying disorders, but if a prescribing physician is borderline on diagnosing an ADHD child with an additional auditory processing disorder, the presence or absence of a comorbid separation anxiety disorder or persistence of oppositional behavior may prove to be a potentially useful tool for pointing the physician in the right direction if the Ghanizadeh study findings are verified and replicated by additional works.