Factors influencing the relationship between cochlear health measures and speech recognition in cochlear implant users

Background

One factor which influences the speech intelligibility of cochlear implant (CI) users is the number and the extent of the functionality of spiral ganglion neurons (SGNs), referred to as "cochlear health." To explain the interindividual variability in speech perception of CI users, a clinically applicable estimate of cochlear health could be insightful. The change in the slope of the electrically evoked compound action potentials (eCAP), amplitude growth function (AGF) as a response to increased interphase gap (IPG) (IPGE_slope) has been introduced as a potential measure of cochlear health. Although this measure has been widely used in research, its relationship to other parameters requires further investigation.

Methods

This study investigated the relationship between IPGE_slope, demographics and speech intelligibility by (1) considering the relative importance of each frequency band to speech perception, and (2) investigating the effect of the stimulus polarity of the stimulating pulse. The eCAPs were measured in three different conditions: (1) Forward masking with anodic-leading (FMA) pulse, (2) Forward masking with cathodic-leading (FMC) pulse, and (3) with alternating polarity (AP). This allowed the investigation of the effect of polarity on the diagnosis of cochlear health. For an accurate investigation of the correlation between IPGE_slope and speech intelligibility, a weighting function was applied to the measured IPGE_slopes on each electrode in the array to consider the relative importance of each frequency band for speech perception. A weighted Pearson correlation analysis was also applied to compensate for the effect of missing data by giving higher weights to the ears with more successful IPGE_slope measurements.

Results

A significant correlation was observed between IPGE_slope and speech perception in both quiet and noise for between-subject data especially when the relative importance of frequency bands was considered. A strong and significant correlation was also observed between IPGE_slope and age when stimulation was performed with cathodic-leading pulses but not for the anodic-leading pulse condition.

Conclusion

Based on the outcome of this study it can be concluded that IPGE_slope has potential as a relevant clinical measure indicative of cochlear health and its relationship to speech intelligibility. The polarity of the stimulating pulse could influence the diagnostic potential of IPGE_slope.

Paricalcitol counteracts the increased contrast induced nephropathy caused by renin-angiotensin-aldosterone system blockade therapy in a rat model

OBJECTIVE

The effect of vitamin D and renin-angiotensin-aldosterone system blockade medications in pathophysiology of contrast induced nephropathy (CIN) is controversial. The effects of paricalcitol (active vitamin D analogue) and losartan treatments in an experimental model of CIN were investigated in this study.

MATERIALS AND METHODS

Thirty-six male Wistar albino rats were examined in five treatment groups. Placebo group (Group A; n = 4) received no active medication; control group (Group B; n = 8) received only contrast media (CM); Group C (n = 8) received paricalcitol; Group D (n = 8) received losartan and Group E (n = 8) received paricalcitol plus losartan. CIN was induced by NG-nitro-L-arginine methyl ester and indomethacin before iohexol injection. Renal histopathological findings were categorized and renal immunohistochemical examinations by caspase-3 rabbit primary antibody were performed.

RESULTS

Creatinine and cystatin C levels significantly increased in the treatment groups, compared to Group A. However, creatinine levels were not significantly increased in Groups C, D and E compared to Group B. Compared to Group B, a significant increase of cystatin C levels was observed in Group D (p < 0.01). In Group E, when paricalcitol treatment was added to losartan treatment, cystatin C levels were similar to Group B (p = 1.00). In histopathological and immunohistochemical examination frequency of Grade 2/3 tubular necrosis and renal caspase 3 activity scores were significantly higher in the losartan treatment group compared to the other treatment groups. The histopathological effects related to losartan treatment were found to be reversed when paricalcitol treatment was combined.

CONCLUSIONS

Our findings suggest that paricalcitol treatment counteracts increased contrast induced nephropathy caused by losartan. These findings warrant further clinical studies to investigate the benefit of paricalcitol in CIN prophylaxis.

The relationship between antibeta 2 glycoprotein antibodies and SYNTAX score in patients undergoing coronary artery by-pass graft surgery

OBJECTIVE

The SYNTAX Score was recently developed to characterize the coronary vasculature with respect to the number of lesion's location, complexity, and functional impact and it is a quantitative scoring system to assist with patient selection for optimal revascularization strategy between percutaneous coronary intervention (PCI) and coronary artery by-pass surgery (CABG). b2-glycoprotein I (b2GPI), a plasma protein that binds cardiolipin, acts as a modulator of platelet aggregation and coagulation. Antibodies to b2GPI may have a role in atherosclerosis by inducing endothelial cell activation. We investigated the relationship between anti beta 2 GPI and severity of coronary artery stenosis by calculating the SYNTAX Score among patients undergoing CABG surgery.

PATIENTS AND METHODS

We prospectively investigate 612 patients who undergo elective coronary angiography between September 2012 and June 2013. Patients were evaluated for blood chemistry and anti-b2GPI IgA, IgM and IgG. Ninety seven patients with complete biochemical analysis including anti Beta 2 GPI antibodies and undergone CABG have been enrolled in this study. We divided patients in to 2 groups according to the SYNTAX scores. Group 1 included 48 patients with low SYNTAX scores (<23) and group 2 included 49 patients with intermediate and high SYNTAX scores (>23).

RESULTS

There was significant correlation between elevated anti b2GPI IgG levels and higher SYNTAX score which indicate advanced and complex CAD. In this study, lesion complexity increased progressively with increasing anti-b2GPI-IgG type of antibody levels. According to this findings, anti-b2GPI-IgG is a strong predictor of higher SYNTAX score.

CONCLUSIONS

In addition to the traditional risk factors for atherosclerosis, the proinflammatory and procoagulant activities of antiphospholipid antibodies appear to be important risk factors for atherosclerotic occlusive disease.

Is chemotherapy-induced nausea and vomiting lower in smokers?

AIM

Chemotherapy-induced nausea and vomiting (CINV) is not understood completely. The aim of this study is to investigate the effects of smoking on CINV.

METHODS

121 consecutive patients who received cisplatin (≥ 50 mg/m²) based chemotherapy were included in the study. The patients who reported motion sickness, pain, emesis during past pregnancy, emesis history of previous chemotherapy, with Karnofsky score < 70, peptic ulcer, gastroesophageal reflux, migraine, central nervous system metastasis and patients scheduled to receive radiation therapy were excluded from the study. A standard antiemetic treatment was given to all patients. The nausea and vomiting was assessed by the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire. After first cycle of chemotherapy, Grade 2 - 3 nausea and vomiting were questioned.

RESULTS

Grade 2 - 3 nausea and vomiting was higher in non-smokers (p < 0.001). We found that nausea and vomiting in women is more frequent than in men (p < 0.001).

CONCLUSION

In our study we found that smokers had a lower incidence of CINV. Further investigations are needed to confirm the findings of this pilot study.