title: Towards an optimal paradigm for intraoperative auditory nerve monitoring with auditory steady state responses.
abstract: Auditory steady state responses (ASSR) may offer an alternative to brainstem auditory evoked potentials for monitoring of the auditory nerve during surgical procedures. In the current study, we evaluated the influence of noise on ASSR characteristics in total intravenous anesthesia (TIVA). Simulated ASSR in real noise recorded during surgery under TIVA were constructed with known parameters. Influence of amplitude, modulation frequency, averaging sweeps and detection threshold on ASSR were evaluated. High amplitude, more sweeps and a liberal threshold facilitated detection. High amplitude ASSR (80 nV) were detected in up to 45 % with 16 s of data, in 80-90 % with 112 s. Near-threshold ASSR were detected in 0.8-25 %. False positives ranged between 0.3 and 10.3 %. Number of sweeps did not influence false positives. Amplitude errors varied between -61 and +39 % and improved with more averages but not with different thresholds. Modulation rate demonstrated the strongest influence on all parameters. 110 Hz yielded best, 90 Hz the worst results. Choice of parameters strongly influences detection and characteristics of ASSR. Optimal parameters enabled detection after 16 s in 45 %. Due to specific noise characteristics, modulation has a critical impact, which is currently not sufficiently recognized in ASSR studies.
authors: Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany. stefan.rampp@uk-halle.de.
authors: Stefan
authors: http://orcid.org/0000-0002-4826-1520
authors: S
authors: Rampp
authors: Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany.
authors: Leonhard
authors: L
authors: Rensch
authors: Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany.
authors: Sebastian
authors: S
authors: Simmermacher
authors: Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany.
authors: Torsten
authors: T
authors: Rahne
authors: Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany.
authors: Christian
authors: C
authors: Strauss
authors: Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06097, Halle (Saale), Germany.
authors: Julian
authors: J
authors: Prell
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000758:Anesthesia / Q000379:methods; D001309:Auditory Threshold; D001933:Brain Stem / Q000473:pathology; D003056:Cochlear Nerve / Q000473:pathology*; D005072:Evoked Potentials, Auditory; D016057:Evoked Potentials, Auditory, Brain Stem; D005153:Facial Neoplasms / Q000601:surgery; D005189:False Positive Reactions; D005260:Female; D006309:Hearing; D006801:Humans; D008297:Male; D008579:Meningioma / Q000601:surgery; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009442:Neurilemmoma / Q000601:surgery; D009464:Neuroma, Acoustic / Q000601:surgery; D009622:Noise
keywords: Anesthesia; Auditory nerve; Auditory steady state response; Hearing; Intraoperative monitoring