Distortion product otoacoustic emissions in school children: Effects to gender, ear asymmetry and handedness

Accurate interpretation of distortion product otoacoustic emission (DPOAE) data cannot be made without realizing the effects of non-pathological factors on DPOAEs. The present study aimed to examine the effects of ear asymmetry, gender and handedness on DPOAEs obtained from school children. One thousand and three children (528 boys and 475 girls) with a mean age of 6.2 years (SD = 0.4, range = 5.2 7.9 years) were tested in a quiet room at their schools using the GSI-60 DPOAE system. The stimuli consisted of two pure tones of different frequencies f1 and f2 presented at 65 and 55dB SPL respectively. A DP-gram was obtained for each ear with f2 varying from 1.1 to 6.0 kHz and the ratio of f2/f1 being kept at 1.21. The signal-to-noise ratios (SNR) (DPOAE amplitude minus the mean noise floor) at the tested frequencies 1.1, 1.5, 1.9, 2.4, 3.0, 3.8, 4.8, and 6.0 kHz were measured. The results revealed a small, but significant difference in SNR between ears, with right ears showing a higher mean SNR than left ears at 1.9, 3.0, 3.8 and 6.0 kHz. At these frequencies, the difference in mean SNR between ears was less than 1 dB. A significant gender effect was also found, with girls exhibiting a higher SNR than boys at 3.8, 4.8 and 6.0 kHz. The difference in mean SNR, as a result of the gender effect, was about 1 to 2 dB at these frequencies. The results from the present study indicated no significant difference in mean SNR between left-handed and right-handed children for all tested frequencies. In conclusion, these non-pathological characteristics of DPOAEs should be considered in the interpretation of DPOAE results for school children.

Refractive error and visual impairment in school children in Northern Ireland

To describe the prevalence of refractive error (myopia and hyperopia) and visual impairment in a representative sample of white school children.

Structured engagement in the extended enterprise

Discusses the necessity for the conscious recognition of the phenomenon known as the extended enterprise; this demands that product, process and supply chain design are all considered simultaneously. Structure must be given to the extended enterprise in order to understand and manage it efficaciously. The authors discuss multiple perspectives for doing this, and employ the notions of “3-dimensional concurrent engineering” and “holonic thinking” for conceiving what the structure may look like. Describes a current “action research” project that is investigating potential lead-time reductions within an extended enterprise’s product introduction process. This aims to produce process visualisations, a framework for structuring and sychronising phases and stage-gates within the extended enterprise, and a new simulation tool which will provide a synthetic distributed hypermedia network. These deliverables will be used to play strategic “games” to explore problem issues within the product introduction process that belongs to the extended enterprise, develop teamwork across autonomous companies, and ultimately, contribute to the design of future extended enterprise supply chains.