The Link Between Central Auditory Processing Disorder (CAPD) and Smoking
As if we haven’t been given enough reasons to refrain from smoking, The Journal of Physiology published an article this spring describing the harmful auditory effects of perinatal nicotine exposure (full article here). Based on this research using animal models, children that are exposed to nicotine both in utero and after birth may develop abnormal auditory brainstem responses. An abnormal auditory brainstem response can cause delayed or atypical development during childhood including auditory processing deficits, delayed speech development, and learning difficulties. But what does this mean?
An auditory processing deficit is not synonymous with a loss of hearing. In fact, one hallmark of auditory processing disorder is normal outer, middle, and cochlear or inner ear structure and function. The deficit lies in the transmission of sound from ear level to brain level, meaning this is a central nervous system deficit. Sound is picked up appropriately by the healthy ear, but it is not effectively discerned by the brain after traveling along the vestibulocochlear nerve and enters the neuronal structure of the auditory pathway.
So what can an auditory processing disorder look like? Symptoms can include but are not limited to:
Difficulty understanding speech in noisy environments
Difficulty differentiating between similar sounds
Unable to follow extensive list of directions or remember large amounts of information given verbally at one time
Trouble with temporal or timing cues
Requiring visual cues to understand information
Asking for repetition repeatedly
In children, the presentation of APD can be misdiagnosed as a specific language impairment (SLI), developmental dyslexia, or attention deficit disorder (ADD). Diagnosis of a child is often determined by the specialized health care professional that is seen initially, whether that is an audiologist, speech pathologist, or psychiatrist. An audiologist is the healthcare provider to perform accurate diagnostic testing and offer management options for those with a true auditory processing deficit.
TLDR; there are auditory processing deficits that occur in people with otherwise healthy ears and normal hearing. Seek the expertise of an audiologist who specializes in auditory processing disorders if you or your child are experiencing any of the symptoms above. Also…just to reiterate the starting point… nicotine exposure is harmful to children both peri- and postnatal. The more you know!