ABSTRACT
OBJECTIVE: To quantify the bystander-effect of 2.5G mobile telephones (2.5G-MTs) on the speech perception of digital hearing-aid (dHA) users. Differences in the susceptibility of behind-the-ear (BTE) compared to in-to-the-ear (ITE) dHAs were also assessed. MATERIALS/METHODS: Prospective-comparative study conducted at a tertiary referral centre (ENT Department) and a HA-fitting laboratory. Key-word recognition scores from open-sentence lists were calculated. Power-analysis determined that a minimum of 60 subjects with SNHL (30 in each group), using either BTE or ITE dHAs, were required for reliable study outcomes. Sixty-four adults were tested with a functioning 2.5G-MT at almost physical contact with their ear; thirty subjects used BTE and 34 ITE dHAs. MAIN OUTCOME MEASURES: Aided word recognition score differences between studied groups and within each group, while a 2.5G-MT was activated. Cut-off inclusion criterion regarding baseline aided word recognition score was 75%. RESULTS: Baseline aided word recognition scores for ITE dHAs were better compared to BTE ones (p < 0.01). Following the 2.5G-MT activation, this difference disappeared. No statistically significant difference in word recognition was observed between the examined groups, or within the BTE group, from the bystander-effect of the 2.5G-MT. ITE dHAs proved more susceptible to electromagnetic interference (p < 0.05). CONCLUSION: The bystander-effect of 2.5G-MTs on the speech perception of dHA users is either minimal, or not significant. The observed compatibility has a positive impact on the lives of millions of people worldwide. The long-standing theory of more interference in BTE compared to ITE HAs is not confirmed by the results of the present study. EBM level of evidence: 2c.
Subject(s)
Cell Phone , Hearing Aids , Hearing Loss, Sensorineural/physiopathology , Hearing Loss, Sensorineural/therapy , Speech Perception/physiology , Adult , Aged , Auditory Threshold , Female , Humans , Male , Middle Aged , Perceptual Masking , Prospective StudiesABSTRACT
Photodynamic therapy (PDT) was recently introduced in clinical practice for the management of cancer. As far as PDT relies on the combined action of a photosensitizer and a laser source, there is a need to evaluate the genotoxic and mutagenic potential of this treatment modality. This paper reports the effects of various photosensitizer and photo-irradiation doses on lethality to the MIA PaCa cell line using ZnPcS4 as the photosensitizer. The sister chromatid exchange (SCE) assay was used to evaluate the genotoxicity of various photosensitizer and photo-irradiation doses. Also, chromosomal aberrations at various time intervals post-irradiation were evaluated. The results showed that a combination of 3 J/cm2 irradiance with 5 microM ZnPcS4 concentration leads to the LD90 72 h post-irradiation. Eight days post-irradiation the LD90 level was achieved using a light dose of 3 J/cm2, independent of ZnPcS4 concentration. The SCE assay showed that cells treated with various light and drug doses presented no genotoxic potential, as SCE levels were not different from untreated (control) cells. Chromosomal analysis after PDT treatment at various time intervals post-irradiation showed that there was no significant chromosomal damage in cells treated photodynamically compared with untreated controls. The results show that the cell killing mechanism after PDT is not at the chromosome level, but may be at a different cellular level, such as plasma membranes, mitochondria, etc.
