Audiovestibular Characteristics of Small Cochleovestibular Schwannomas in Neurofibromatosis Type 2.
Describe the relationship between cochleovestibular schwannoma (CVS) volume, audiovestibular characteristics, and magnetic resonance imaging (MRI) findings in patients with neurofibromatosis type 2 (NF2).



Subgroup analysis of NF2 prospective natural history study from 2008 to 2011.



Quaternary medical research institute.



NF2 patients with small treatment-naive CVSs (volume <1000 mm(3)) by ear; N = 49 ears (32 patients). Cross-sectional analysis of the following parameters was performed: tumor size, auditory brainstem response (ABR), 4-frequency pure-tone average (4f-PTA; 0.5, 1, 2, and 4KHz), cervical vestibular evoked myogenic potential (cVEMP), caloric testing, 240° velocity step test (VST), and MRI findings.



For all physiologic measures but the 4f-PTA, larger tumors correlated with abnormal responses (P < .05). For abnormal ABR, mean tumor volume was 405 vs 151 mm(3) (P = .0007) for normal ABR. Similarly, larger tumors correlated with weak caloric responses (mean 521 vs 165 mm(3); P = .0007) and weak cVEMP (mean 357 vs 192 mm(3); P = .0262). Tumor volume was not significantly correlated with 4f-PTA. Elevated intralabyrinthine protein on MRI fluid-attenuated inversion recovery sequences was correlated with larger tumor volume (mean 333 vs 55 mm(3); P = .001) and abnormal ABR and 4f-PTA (P < .05) but did not correlate with cVEMP, VST, or caloric responses.



In our cohort, ABR, caloric response, cVEMP, and elevated intralabyrinthine protein correlated with tumor volume, but 4f-PTA did not. Abnormal ABR and 4f-PTA correlated with elevated intralabyrinthine protein. These findings may provide insight on the effect of small CVS on the inner ear and cochleovestibular nerves, which may aid in their optimal management.
Department of Otolaryngology-Head and Neck Surgery, Georgetown University Hospital, Washington, DC, USA michael.a.holliday@gunet.georgetown.edu.
Michael A
MA
Holliday
Department of Otolaryngology-Head and Neck Surgery, Georgetown University Hospital, Washington, DC, USA Office of Clinical Director, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA.
Hung Jeffrey
HJ
Kim
Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA.
Christopher K
CK
Zalewski
Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA.
Talah
T
Wafa
Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
Ramita
R
Dewan
Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA.
Kelly A
KA
King
Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA.
Carmen C
CC
Brewer
Radiology and Imaging Sciences, The Clinical Center at the National Institutes of Health, National Institutes of Health, Bethesda, Maryland, USA.
John A
JA
Butman
Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
Ashok R
AR
Asthagiri
D000293:Adolescent; D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone / Q000379:methods; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D034381:Hearing Loss / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016518:Neurofibromatosis 2 / Q000150:complications; D009464:Neuroma, Acoustic / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D011446:Prospective Studies; D058585:Vestibular Evoked Myogenic Potentials
ABER; ABR; MRI; VEMP; audiogram; caloric tests; neurofibromatosis type 2; vestibular tests