Sriram Boothalingam, PhD
Position title: Assistant Professor, Communication Sciences and Disorders
PhD, Western University, Canada
Assistant Professor, Communication Sciences and Disorders
1500 Highland Avenue
Madison, WI 53705
The focal point of our lab’s research is the auditory efferent system. The auditory efferent system is a rich neural network originating in the auditory cortex and terminating in the ear. En route, it forms multiple feedback loops within the brain and acts as a control system by regulating the electrical activity of afferent auditory neurons as well the mechanical activity of the ear. Efferent control has been implicated in aiding hearing in noisy backgrounds, protecting the inner ear from noise damage, and in mediating attention to the auditory periphery. While a great deal has been learned about the functioning of certain efferent loops, little is known about the role of the auditory cortex in controlling human hearing, especially in children. Our current work focusses on teasing apart the role of multiple efferent loops and their functional relevance for children and adults. Another line of work in our lab is aimed at developing clinical tools to objectively test the auditory afferent and efferent systems. Our lab is also interested in investigating maturational trajectories of the auditory efferents and the cochlea, especially the apical half. We use otoacoustic emissions (OAEs) to measure acoustic, and electroencephalography (EEG) to measure electrical, responses from the auditory system. OAEs are extra energy generated by healthy ears that are measured in the ear canal as sound. Both OAEs and EEG are objective non-invasive methods that do not require participants to actively participate in the test and are therefore well suited in infants and children.
In our previous works, we have studied the role of cochlear processing and efferent activity in children with auditory processing disorders. This work brought to light the subtle discrepancies in cochlear processing among children, such as sharpness of tuning, which typically goes unnoticed. A further development of this work has revealed that subtle processing aberrations in the cochlea can affect neural coding of sounds. In a related work, we found that children localize speech on par with adults in quiet but are affected by noise more than adults, suggesting that children require a greater signal-to-noise ratio to perform the same auditory task. This finding has implications for classroom acoustics and other learning areas. In other studies, we have investigated basic physiology of the auditory system in response to sound. Contributions from these studies will help researchers and clinicians in guiding their research and clinical methods, respectively.
Boothalingam S, Purcell DW, Allan C, Allen P, Macpherson E. (2019). Auditory Localization and Spatial Release From Masking in Children With Suspected Auditory Processing Disorder. Ear and Hearing, 40(5):1187-1196. doi: 10.1097/AUD.0000000000000703.
Boothalingam S, Allan C, Allen P, Purcell DW. (2019). The Medial Olivocochlear Reflex Is Unlikely to Play a Role in Listening Difficulties in Children. Trends in Hearing, 23:2331216519870942. doi: 10.1177/2331216519870942. PMID: 31558110; PMCID: PMC6767729.
Boothalingam S, Kurke J, Dhar S. (2018). Click-Evoked Auditory Efferent Activity: Rate and Level Effects. Journal of the Association for Research in Otolaryngology, 19(4):421-434. doi: 10.1007/s10162-018-0664-x.
Boothalingam S, Macpherson E, Allan C, Allen P, Purcell D. (2016) Localization-in-noise and binaural medial olivocochlear functioning in children and young adults. Journal of the Acoustical Society of America. 139(1):247-62. doi: 10.1121/1.4939708.
Zhao W, Dewey JB, Boothalingam S, Dhar S. (2015) Efferent Modulation of Stimulus Frequency Otoacoustic Emission Fine Structure. Frontiers in Systems Neuroscience, 10;9:168. doi: 10.3389/fnsys.2015.00168.
Boothalingam S, Allan C, Allen P, Purcell D. (2015) Cochlear Delay and Medial Olivocochlear Functioning in Children with Suspected Auditory Processing Disorder. PLoS One, 10(8):e0136906. doi: 10.1371/journal.pone.0136906.
Boothalingam S, Purcell DW. (2015) Influence of the stimulus presentation rate on medial olivocochlear system assays. Journal of the Acoustical Society of America, 137(2):724-32. doi: 10.1121/1.4906250.
Boothalingam S, Purcell D, Scollie S. (2014) Influence of 100Hz amplitude modulation on the human medial olivocochlear reflex. Neuroscience Letters, 19;580:56-61. doi: 10.1016/j.neulet.2014.07.048.
Boothalingam S, Lineton B. (2012) Effect of contralateral acoustic stimulation on cochlear tuning measured using stimulus frequency and distortion product OAEs. International Journal of Audiology, 51(12):892-9. doi: 10.3109/14992027.2012.709641.