Sensorineural Hearing Loss Affects Functional Connectivity of the Auditory Cortex, Parahippocampal Gyrus and Inferior Prefrontal Gyrus in Tinnitus Patients.

Background: Tinnitus can interfere with a patient's speech discrimination, but whether tinnitus itself or the accompanying sensorineural hearing loss (SNHL) causes this interference is still unclear. We analyzed event-related electroencephalograms (EEGs) to observe auditory-related brain function and explore the possible effects of SNHL on auditory processing in tinnitus patients. Methods: Speech discrimination scores (SDSs) were recorded in 21 healthy control subjects, 24 tinnitus patients, 24 SNHL patients, and 27 patients with both SNHL and tinnitus. EEGs were collected under an oddball paradigm. Then, the mismatch negativity (MMN) amplitude and latency, the clustering coefficient and average path length of the whole network in the tinnitus and SNHL groups were compared with those in the control group. Additionally, we analyzed the intergroup differences in functional connectivity among the primary auditory cortex (AC), parahippocampal gyrus (PHG), and inferior frontal gyrus (IFG). Results: SNHL patients with or without tinnitus had lower SDSs than the control subjects. Compared with control subjects, tinnitus patients with or without SNHL had decreased MMN amplitudes, and SNHL patients had longer MMN latencies. Tinnitus patients without SNHL had a smaller clustering coefficient and a longer whole-brain average path length than the control subjects. SNHL patients with or without tinnitus had a smaller clustering coefficient and a longer average path length than patients with tinnitus alone. The connectivity strength from the AC to the PHG and IFG was lower on the affected side in tinnitus patients than that in control subjects; the connectivity strength from the PHG to the IFG was also lower on the affected side in tinnitus patients than that in control subjects. However, the connectivity strength from the IFG to the AC was stronger in tinnitus patients than that in the control subjects. In SNHL patients with or without tinnitus, these changes were magnified. Conclusion: Changes in auditory processing in tinnitus patients do not influence SDSs. Instead, SNHL might cause the activity of the AC, PHG and IFG to change, resulting in impaired speech recognition in tinnitus patients with SNHL.

Id1/NR2B Receptor Pathway Regulates Rat Cochlear Sensory Epithelial Cell Survival after Radiation.

Survival of cochlear sensory epithelial cells may be regulated by inhibitor of differentiation-1 (Id1) and the N-methyl-D-aspartic acid (NMDA) receptor. However, it is unclear whether Id1 and the NMDA receptor are involved in the radiation-mediated survival of rat cochlear sensory epithelial cells. Here, we show that the percentage of apoptotic cells increased, the percentage of cells in the S phase decreased, Id1 mRNA and protein expression decreased and the NMDA receptor subtype 2B (NR2B) mRNA and protein level increased in OC1 cells after radiation. Cells infected with the Id1 gene exhibited higher Id1 mRNA and protein levels and lower NR2B mRNA and protein levels than the control cells. In contrast, after transfection of the Id1 siRNA into OC1 cells, Id1 mRNA and protein expression decreased and NR2B mRNA and protein expression increased relative to that of the control group. Additionally, treatment with ifenprodil for 24 h before radiation reduced apoptosis and increased the percentage of cells in the S phase. Our results suggest that Id1 and NR2B might regulate the survival of OC1 cells following radiation.

Multidisciplinary Care of Unruptured Brain Arteriovenous Malformations to Improve Symptomatic Headache and the Onset, Progression, and Outcomes of Unruptured Brain Arteriovenous Malformations.

BACKGROUND: Symptomatic headaches attributed to unruptured brain arteriovenous malformations (ubAVMs) are very common and affect patients' quality life, but multidisciplinary care of ubAVMs to improve symptomatic headache remains unclear. OBJECTIVE: The objective is to identify the features of symptomatic headaches, and to obtain headache outcomes following multidisciplinary care of ubAVMs, as well as provide background on the natural history of ubAVMs. STUDY DESIGN: The features of symptomatic headaches and headache outcomes were analyzed in a large cohort of cases after multidisciplinary care of ubAVMs. We have also provided information on the natural history of ubAVMs. SETTING: This study was conducted at the Department of Neurosurgery of Zhujiang Hospital where 336 patients from 1998 to 2014 were reviewed by a multidiscipline team. Only 124 patients were eligible. METHODS: The demographics, clinical features, imaging features, and headache details of eligible patients were reviewed. An 11-point pain scale score was used to assess symptomatic headaches before, during, and after treatment. The headache outcomes, death or stroke, and adverse functional outcomes (modified Rankin Scale score = 2, mRS = 2) were assessed following multidisciplinary care of ubAVMs. RESULTS: Twenty-three (56.1%) of 41 patients had migraine-like headaches located in occipital lobe (P < 0.001), while forty (63.5%) of 63 patients had tension-type-like headaches located in frontotemporal lobe (P < 0.001). For patients with tension-type-like or all types of headache, headache improvement differed between the multidisciplinary group and medical group (87.8% vs. 31.8%, P < 0.001; 85.7% vs. 40.7%, P < 0.001). The risk of death or stroke did not differ between multidisciplinary group and medical group (P = 0.393), whereas the risk of adverse functional outcome (mRS = 2) differed significantly by long-time follow-up (23.0% vs.10.0%, P = 0.022). LIMITATIONS: This study provides the initial experience to support multidisciplinary care for ubAVMs to improve symptomatic headaches and patients' quality life, but based on the retrospective study with inherent limitations, larger samples and multi-center trials are needed on this interesting issue. CONCLUSIONS: Occipital ubAVM is more likely to present with migraine-like headache, while frontotemporal ubAVM tends to present with tension-type-like headache. The effectiveness of multidisciplinary care for ubAVM to improve headache has been shown, but the natural history of ubAVM patients with headache remains unclear.Key Words: Unruptured brain arteriovenous malformations, headache, headache improvement, natural history.

[Applied anatomy of facial recess and posterior tympanum related to cochlear implantation].

OBJECTIVE: To investigate the related parameters of temporal bone structure in the surgery of cochlear implantation through facial recess approach so as to offer a theoretical reference for the avoidance of facial nerve injury and the accurate localization. METHOD: In a surgical simulation experiment, twenty human temporal bones were studied. The correlation parameters were measured under surgical microscope. RESULT: Distance between suprameatal spine and short process of incus was (12.44 +/- 0.51) mm. Width from crotch of chorda tympani nerve to stylomastoid foramen was (2.67 +/- 0.51) mm. Distance between short process of incus and crotch of chorda tympani nerve was (15.22 +/- 0.83) mm. The location of maximal width of the facial recess into short process of incus, crotch of chorda tympani nerve were (6.28 +/- 0.41) mm, (9.81 +/- 0.71) mm, respectively. The maximal width of the facial recess was (2.73 +/- 0.20) mm. The value at level of stapes and round window were (2.48 +/- 0.20 mm) and (2.24 +/- 0.18) mm, respectively. Distance between pyramidalis eminence and anterior round window was (2.22 +/- 0.21) mm. Width from stapes to underneath round window was (2.16 +/- 0.14) mm. CONCLUSION: These parameters provide a reference value to determine the position of cochlear inserting the electrode array into the scale tympani and opening facial recess firstly to avoid potential damage to facial nerve in surgery.

[Applied anatomy of scala tympani inlet related to cochlear implantation].

OBJECTIVE: To investigate the related parameters of the temporal bone structure for determining the position of implanting electrode into the scala tympani in cochlear implantation surgery through the facial recess and epitympanum approach. METHODS: In a surgical simulation experiment, 20 human temporal bones were studied and measured to determine the related parameters of the temporal bone structure. RESULTS: The distance 5.91∓0.29 mm between the short process of the incus and the round window niche, 2.11∓0.18 mm between the stapes and the round window niche, 6.70∓0.19 mm between the facial nerve in the perpendicular paragraph and the round window niche, 2.22∓0.21 mm from the pyramidal eminence to the round window, and 2.16∓0.14 mm between the stapes and the round window. The minimal distance between the implanting electrode and the vestibular window was 2.12∓0.19 mm. The distance between the cochleariform process and the round window niche was 3.79∓0.17 mm. The position of the cochlear electrode array insertion into the second cochlear turn was 2.25∓0.13 mm under the stapes. The location of the cochlear electrode array insertion into the second cochlear turn was 2.28∓0.20 mm inferior to the pyramidal eminence. CONCLUSION: These parameters provide a reference value to determine the different positions of cochlear electrode array insertion into the scale tympani in different patients.