Otolaryngology

Impact of White Matter Hyperintensities on Speech Perception Performance in Patients for Cochlear Implant Evaluation

Faculty Mentor’s Name: Dr. Si Chen
Email: sichen1@ufl.edu
Phone Number: (305) 849-3004
Project Category: Clinical
International Component or Travel: No

Project Description:
Background: Speech comprehension is a multisystem process that can be impaired at multiple levels from the peripheral hearing organ (inner ear), cochlear nerve, brainstem, to cerebral cortex. A properly functioning inner ear is essential for sound detection, however, multiple bidirectional pathways from the inner ear to the cerebral cortex are involved for attributing meaning to a sequence of sound, namely speech comprehension. Individuals who suffer from profound sensorineural hearing loss (SNHL) have increasing difficulty understanding speech, such as older patients diagnosed with presbycusis or age-related hearing impairment (ARHI) (1). When SNHL is severe enough, patients meet criteria for surgical implantation of a neuroprosthetic known as a cochlear implant. These devices transform acoustic sound signals into an electric stimulus that is directly applied to the inner ear (5). Cochlear implants have been shown to drastically improve the quality of life and speech comprehension in both children and adults (2, 3).
White matter hyperintensities (WMH) on magnetic resonance imaging (MRI)’s are radiological findings that have corresponded to areas of inflammation and gliosis when studying gross brain specimens (4, 10). Past studies have noted the effect that brain WMH may have on central processing (CP) of speech (6). CP occurring in the central nervous system (CNS) is vital in decoding the electrical stimulus provided by the inner ear in order to understand speech. When CNS is affected by processes such as aging or Alzheimer’s dementia, central processing is impaired. Once thought to be incidental findings without significant clinical relevance, WMH’s have been correlated to specific neurological diseases (i.e Alzheimer’s disease, vascular dementia, multiple sclerosis) (7 – 9). More recently, researchers found that there is a negative correlation between increasing number of brain WMH’s and scores on speech perception tests (SPT) (11). The authors studied patients with mild high-frequency SNHL and found that their sound detection threshold (pure tone audiometry) did not correlate with SPT, but the grade of WMH correlated with SPT. It suggests that despite relatively normal inner ear function, WMH played a role in speech comprehension. Further studies are needed to confirm whether increasing WMH represents increasing impairment of CP thus impede speech perception.
It is unclear how WMH’s affect the speech perception of patients with severe to profound sensorineural hearing loss, such as those requiring cochlear implantation. With impaired peripheral auditory organ, the patient increasingly relies on CP to decode sound and understand speech. MRI abnormalities have been examined in children with congenital SNHL (12-15) but there is no previous published study that examined WMH in adult cochlear implant patients. We have performed retrospective review of speech performance in cochlear implant patients. Preliminary results support that WMH may contribute to worse speech understand score. There has been no prospective study to confirm the finding. We hypothesize that WMH is associated with worse speech understanding scores before and after cochlear implant.

Methods: This will be a prospective study of patients who will undergo cochlear implant evaluation at University of Florida Cochlear Implant Program (UFCIP). Cochlear implant patients age 18 and older will be recruited at the time of their cochlear implant evaluation appointment with the principal investigator and audiologists.
Exclusion criteria are: incomplete medical record, lack of adequate MRI images, incomplete cochlear implant evaluation, prelingual deafness, developmental delay, cochlear implant surgery complications, known neurologic disorders including Alzheimers, Parkinsons, dementia, multiple sclerosis, stroke, congenital brain abnormalities, radiation to the head and neck, tumors of the brain, surgery of the brain, trauma to the head that resulted in a fracture.
Study subjects will undergo MRI brain as a standard part of CI evaluation. The MRI images will be reviewed by neuroradiologist for WMH burden with Fazekas score. Study subjects will also undergo speech performance evaluation as a routine part of CI evaluation with the audiologists. These speech performance measures include bilateral pure tone thresholds, speech recognition threshold (SRT), word recognition score (WRS), consonant-nucleus-consonant (CNC) word list score, individual and binaural AzBIO sentence scores in quiet and noise, and Montreal Cognitive Assessment (MOCA) score.

Role of Medical Student:
1. Assist in recruitment of patients from otolaryngology and audiology clinics, specifically patients who present for cochlear implant evaluations.
2. Obtain informed consent for participation in the project.
3. Coordinate appropriate otolaryngology, audiology, and radiology evaluations.
4. Enter data from cochlear implant evaluations.
5. Participate in abstract and manuscript writing after completion of project.

References:
1. Wang J, Puel JL. Presbycusis: An Update on Cochlear Mechanisms and Therapies. J Clin Med. 2020;9(1):218. Published 2020 Jan 14.
2. Pooresmaeil E, Mohamadi R, Ghorbani A, Kamali M. The relationship between comprehension of syntax and reading comprehension in cochlear implanted and hearing children. Int J Pediatr Otorhinolaryngol. 2019;121:114‐119.
3. Sousa AF, Couto MIV, Martinho-Carvalho AC. Quality of life and cochlear implant: results in adults with postlingual hearing loss. Braz J Otorhinolaryngol. 2018;84(4):494‐499.
4. Wardlaw, J. M., Valdés Hernández, M. C., & Muñoz‐Maniega, S. (2016). What are White Matter Hyperintensities Made of? Journal of the American Heart Association, 5(1).
5. Adunka O, Kiefer J. Wie funktioniert der Sprachprozessor von Cochlea-Implantaten? [How does a cochlear implant speech processor work?]. Laryngorhinootologie. 2005;84(11):841‐854.
6. Lyu B, Choi HS, Marslen-Wilson WD, Clarke A, Randall B, Tyler LK (2019) Neural dynamics of semantic composition. Proc Natl Acad Sci U S A 116:21318–21327.
7. Vernooij MW, Ikram MA, Tanghe HL, Vincent AJ, Hofman A, Krestin GP, Niessen WJ, Breteler MM, van der Lugt A (2007) Incidental findings on brain MRI in the general population. N Engl J Med 357(18):1821–1828
8. Altamura C, Scrascia F, Quattrocchi CC, et al. Regional MRI Diffusion, White-Matter Hyperintensities, and Cognitive Function in Alzheimer’s Disease and Vascular Dementia. J Clin Neurol. 2016;12(2):201‐208.
9. Datta G, Colasanti A, Rabiner EA, Gunn RN, Malik O, Ciccarelli O, Nicholas R, Van Vlierberghe E, Van Hecke W, Searle G, Santos- Ribeiro A, Matthews PM (2017) Neuroinflammation and its rela- tionship to changes in brain volume and white matter lesions in multiple sclerosis. Brain. 140:2927–2938.
10. Braffman BH, Zimmerman RA, Trojanowski JQ, Gonatas NK, Hickey WF, Schlaepfer WW (1988) Brain MR: pathologic correlation with gross and histopathology. Hyperintense white-matter foci in the elderly. AJR Am J Roentgenol 151:559–566
11. Di Stadio A, Messineo D, Ralli M, et al. The impact of white matter hyperintensities on speech perception [published online ahead of print, 2020 Feb 24]. Neurol Sci. 2020;10.1007/s10072-020-04295-8.
12. Xu XQ, Wu FY, Hu H, Su GY, Shen J. Incidence of Brain Abnormalities Detected on Preoperative Brain MR Imaging and Their Effect on the Outcome of Cochlear Implantation in Children with Sensorineural Hearing Loss. Int J Biomed Imaging. 2015;2015:275786.
13. Wu C, Huang L, Tan H, Wang Y, Zheng H, Kong L, Zheng W. Diffusion tensor imaging and MR spectroscopy of microstructural alterations and metabolite concentration changes in the auditory neural pathway of pediatric congenital sensorineural hearing loss patients. Brain Res. 2016 May 15;1639:228-34.
14. Wang H, Liang Y, Fan W, Zhou X, Huang M, Shi G, Yu H, Shen G.
DTI study on rehabilitation of the congenital deafness auditory pathway and speech center by cochlear implantation. Eur Arch Otorhinolaryngol. 2019 Sep;276(9):2411-2417.
15. Huang L1, Zheng W1, Wu C1, Wei X2, Wu X2, Wang Y1, Zheng H. Diffusion Tensor Imaging of the Auditory Neural Pathway for Clinical Outcome of Cochlear Implantation in Pediatric Congenital Sensorineural Hearing Loss Patients. PLoS One. 2015 Oct 20;10(10):e0140643.