The role of auditory processing in concussions, ADHD and APD

         One of the most common brain injuries seen are concussions, or mild traumatic brain injury (mTBI). Concussions can be a result of direct impact such as falling or sports collisions, or from indirect force such as whiplash where your head snaps forward or back. Despite the awareness of concussions, they tend to be difficult to diagnose as they do not show up on CT or MRI scans, they lack specific symptoms and could be misinterpreted as symptoms of other conditions, and they are subjective, or self-reported which may not be dependable and may be biased. It is imperative for concussions to be diagnosed, and an objective test be designed because of the potential for concussions to impact cognition, neurologic function, socio-emotional wellbeing, and academic achievement [1]. Without a diagnosis, concussions may go unnoticed and thus, untreated.  
     I recently had the pleasure of listening to Dr.Krizman speak during a neuroscience seminar on her phenomenal paper, “Auditory biological marker of concussion in children.” This paper discusses how auditory processing, which can be disrupted by concussions, can be used to identify concussion occurrence and severity [1]. The study followed concussed and non-concussed child athletes and measured auditory processing by using the frequency-following response (FFR). FFRs can capture the fundamental frequency, harmonics, amplitude (intensity), timing, and noise. Fundamental frequency (distinguishing who is talking) and harmonics (distinguishing words) are found to be diminished in concussed patients. The study followed some of the concussed children from Lurie Children’s Hospital to observe recovery and found results of partial recovery. FFR provides clues for biological factors disrupted after a concussion; applying these findings allows the researchers to identify a signature neural profile and opens clinical potential for diagnosing and tracking concussions in patients. 
      Dr.Krizman’s talk made me aware of just how expansive auditory processing is. Auditory processing has many roles in language, reading, filtering, perception, and more. For those reasons, I wanted to know more about the impact of auditory processing in other conditions. While searching, I came across an article about attention deficit hyperactive disorder (ADHD) and auditory processing disorder (APD) and the link between them [2]. ADHD and APD can both affect attention, consequently contributing to the inaccuracy of diagnosis of both conditions. But why are they mistaken? The article discusses the 2017 study [3], “Auditory Processing Assessment in Children with Attention Deficit Hyperactivity Disorder”, where children with ADHD were found to not perform as well on auditory processing tests. However, when treated with methylphenidate (more common brand names are Ritalin or Concerta), ADHD children were found to perform as well as children without ADHD [2, 3]. Therefore, symptoms of challenges in auditory processing can be associated with ADHD. Consequently, APD symptoms can be misdiagnosed and interpreted as the individual having attention deficits. Both conditions require careful evaluation to address them. 
     From both the seminar talk and the article from Medical News Today, I have begun to realize the broader implications of auditory processing (listening behavior) being a direct reflection of neurological conditions in the brain rather than only being involved in hearing. Auditory processing involves auditory memory, attention, distinguishing sounds, blocking background noise, and location of sound. It spans many neural systems and thus, can be implicated in a variety of conditions. If multiple conditions exhibit similar auditory symptoms, clinicians face the challenges of accurately diagnosing. Dr.Krizman’s study [1] introduces a biological marker for concussions, which are known for being difficult to diagnose. It makes me wonder how an auditory biological marker can be applied to other conditions with auditory symptoms like those mentioned in the article by Medical News Today. 
 
References:
1. Kraus, N., Thompson, E. C., Krizman, J., Cook, K., White-Schwoch, T., & LaBella, C. R. (2016). Auditory biological marker of concussion in children. Scientific reports, 6, 39009.  
2. Villines, Z. (2021, November 9). ADHD and auditory processing disorder: Difference, diagnosis, and more. Medical News Today. https://www.medicalnewstoday.com/articles/adhd-and-auditory-processing-disorder 

3. Lanzetta-Valdo, B. P., Oliveira, G. A., Ferreira, J. T., & Palacios, E. M. (2017). Auditory Processing Assessment in Children with Attention Deficit Hyperactivity Disorder: An Open Study Examining Methylphenidate Effects. International archives of otorhinolaryngology, 21(1), 72–78.