PP1322 - Olfactory Dichotic Test: A Potential Tool for Differential Diagnostic of Auditory Processing Disorder and Attention Deficit Hyperactivity Disorder in Children

There is a lack of a "gold standard" test battery and diagnostic criteria for auditory processing disorder. Efforts are made in research to develop new diagnostic tools that use non-auditory modalities and non-linguistic material to establish a differential diagnosis. Therefore, this study explored the dichotic olfactory integration capacity with an odor identification test, which echoes the dichotic listening test, in typically developing children. Results showed significant differences between children’s performance and existing results in adults.

 

Summary:

Auditory Processing Disorder (APD) “is presumed to originate in the auditory system (body functions and structures) and is characterized by a persistent limitation in the performance of auditory activities and significant consequences on participation.” (Canadian Interorganizational Steering Group for Speech-Language Pathology and Audiology, 2012). APD is highly comorbid with other disorders, such as Attention Deficit Hyperactivity Disorder (ADHD). Diagnostic procedures and treatment in children are often delayed because of shared behavioral and learning issues between APD and ADHD. Researchers in the field aim to develop new diagnostic tools by assessing high-level abilities in modalities other than auditory and using non-linguistic material to establish a differential diagnosis of APD. This study explored the olfactory modality. No known study was found on the assessment of olfactory capacities in children with APD. However, such studies were conducted in children with ADHD, but no scientific consensus exists on their olfactory performances.
 

Furthermore, some studies reported a right-nostril dominance when tested separately (Hudry et al., 2014), but was not supported by the results form Zang et al., 2020' study. However, Manescu et al. (2017) explored the nostril dominance while using dichotic olfactory mixtures. A right-nostril dominance in right-handed participants was observed in their first experiment, but could not be replicated with right and left-handed participants in their second one. Further testing with dichotic olfactory tasks is required.

The present study investigated the feasibility of using a new developed olfactory test in typically developing children before assessing children with APD and those with ADHD. This is a dichotic olfactory task which echoes the dichotic listening test used in APD test battery. Moreover, this study aimed to assess the reliability of the test, the age effect when compared to adult results and the link between the two dichotic test performances as well as the association between results of a mononasal test and of the dichotic olfactory test. Also, this study explored nostril dominance, as previously mentioned. 

Participants underwent two auditory tests: hearing thresholds and a dichotic listening test (Jutras et al., 2012) as well as a hand, vision and feet dominance test (adapted from De Agostini & Dellatolas, 1988) to select only right-dominant candidates. After completing a dichotic olfactory test questionnaire (adapted from Cavazzana, 2018), participants also performed three olfactory tests: olfactory threshold, mononasal and dichotic tests . 

Data collection and analysis are still ongoing. Lower performance is expected in children compared to adult performance on the mononasal test and the two dichotic tests. Results in children could reveal good reliability of the newly developed dichotic olfactory test, like the one obtained in adults. Finally, a significant association between mononasal test and olfactory dichotic test performance in children is anticipated, as seen with adult performance. Results might highlight a right-nostril dominance with the dichotic olfactory test.

References: https://docs.google.com/document/d/1Ljh5IumwEZ3MESznGRZitS-UCsMnjaP2/edit?usp=sharing&ouid=104899950196826126502&rtpof=true&sd=true