Objective: To investigate whether the residual hearing of severely hearing-impaired children and adults could be preserved using the soft surgery approach. Patients and Methods: This project employed a prospective study design. All testing and surgery took place in the Institute of Physiology and Pathology of Hearing, Warsaw, Poland. Twenty-six patients (7 children and 19 post-lingually deafened adults) with residual hearing were assessed. Subjects were assessed using conventional pure-tone audiometry at least 1 month prior to surgery. Cochlear implant surgery with a Med-El Combi 40/40+ standard electrode array was conducted, using the soft surgery approach. Pure-tone audiometry thresholds were re-assessed at least 1 month after surgery. The researchers assessed change in auditory thresholds using pure-tone audiometry to determine preservation of residual hearing. Results: Sixteen of 26 patients (62%) retained their residual hearing within 5 dB HL of pre-operative scores. Only 5 of 26 patients (19%) lost all measurable residual hearing after cochlear implantation. This suggests that surgeons are often able to preserve residual hearing during cochlear implant surgery using the soft surgery technique. Conclusions: Preservation of residual hearing is an important consideration in cochlear implantation in the light of changing selection criteria for cochlear implant candidates, and as younger children are receiving implants. This is important, as we do not know yet the long-term effects of inner ear damage due to traumatic insertions of electrodes. This finding suggests a good prognosis for future possibilities of re-implantation.

The activity of rhodanese, 3-mercaptopyruvate sulfurtransferase (MPST) and cystathionase in mouse liver, kidney, and four brain regions: tele-, meso-, di- and rhombencephalon was studied 30 min and 2 h following a sublethal dose of cyanide (4 mg/ kg body weight) intraperitoneal injection. Simultaneously, sulfane sulfur levels and total sulfur content, a direct or indirect source of sulfur for CN(-) conversion to SCN(-), were also investigated in these tissues. In the liver this dose of cyanide seemed to impair the process of cyanide detoxification by MPST, as well as rhodanese inhibition. The effects of cyanide administration to mice proved to be totally different in the liver and kidney. In the kidney, a significant increase in the rhodanese activity was observed as early as 30 min following cyanide intoxication, and an elevated cystathionase activity after 2 h was detected. This suggests the involvement of cystathionase in cyanide detoxification in the kidney. The activity of MPST remained at the same level as in the control group. In the rhombencephalon, similarly as in the kidney, L-cysteine desulfuration pathways, which generate sulfane sulfur and sulfurtransferases that transfer sulfane sulfur atoms to CN(-), seemed to play an important role as a defense system against cyanide. The stable level of sulfane sulfur and total sulfur content was accompanied in the rhombencephalon by an increased activity of MPST, cystathionase and rhodanese. In other brain regions the role of these three sulfurtransferases was not so clear and it seemed that in the telencephalon, where the total sulfur content, but not the sulfane sulfur level, was significantly increased, some sulfur-containing compounds, such as GSH and/or cysteine, appeared in response to cyanide.

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IntroductionThe objective of the presented study was to develop and evaluate a P300 experimental protocol for simultaneous registration of event-related potentials (ERPs) and functional MRI (fMRI) data with continuous imaging. It may be useful for investigating attention and working memory processes in specific populations, such as children and neuropsychiatric patients.Materials and methodsEleven children were investigated with simultaneous ERP–fMRI. To fulfill requirements of both BOLD and electroencephalographic signal registration, a modified oddball task was used. To verify the ERP–fMRI protocol we also performed a study outside the scanner using a typical two-stimuli oddball paradigm.ResultsLocalization of the P300 component of ERPs partially corresponded with fMRI results in the frontal and parietal brain regions. FMRI activations were found in: middle frontal gyrus, insula, SMA, parietal lobule, thalamus, and cerebellum. Our modified oddball task provided ERP–fMRI results with high level of significance (EEG SNR = 35, fMRI p < 0.05–Bonf.). ERPs obtained in the scanner were comparable with those registered outside the scanner, although some differences in the amplitude were noticed, mainly in the N100 component.ConclusionIn our opinion the presented paradigm may be successfully applied for simultaneous ERP–fMRI registration of neural correlates of attention in vulnerable populations.