Getting evidence into policy: The need for deliberative strategies?

Getting evidence into policy is notoriously difficult. In this empirical case study we used document analysis and key informant interviews to explore the Australian federal government’s policy to implement a national bowel cancer screening programme, and the role of evidence in this policy. Our analysis revealed a range of institutional limitations at three levels of national government: within the health department, between government departments, and across the whole of government. These limitations were amplified by the pressures of the 2004 Australian federal election campaign. Traditional knowledge utilisation approaches, which rely principally on voluntarist strategies and focus on the individual, rather than the institutional level, are often insufficient to ensure evidence-based implementation. We propose three alternative models, based on deliberative strategies which have been shown to work in other settings: review of the evidence by a select group of experts whose independence is enshrined in legislation and whose imprimatur is required before policy can proceed; use of an advisory group of experts who consult widely with stakeholders and publish their review findings; or public discussion of the evidence by the media and community groups who act as more direct conduits to the decision-makers than researchers. Such deliberative models could help overcome the limitations on the use of evidence by embedding public review of evidence as the first step in the institutional decision-making processes. Highlights  Achieving evidence-based policy implementation is much harder than the rhetoric suggests.  Our case study showed traditional voluntarist approaches are not enough to overcome institutional filtering of the evidence.  Deliberative strategies open up the decision-making processes to greater expert and public scrutiny.  Our framework illustrates the potential for deliberative strategies to increase the relative weight of evidence in policy.  This article challenges researchers and policy-makers to acknowledge and address the institutional context of decision-making. Keywords: Australia; Health policy; Decision-making; Evidence; Knowledge utilisation; Bowel cancer; Screening; DeliberativeNHMR

Advances in cochlear implant telemetry: evoked neural responses, electrical field imaging, and technical integrity.

Contains fulltext : 53576.pdf (publisher's version ) (Closed access)During the last decade, cochlear implantation has evolved into a well-established treatment of deafness, predominantly because of many improvements in speech processing and the controlled excitation of the auditory nerve. Cochlear implants now also feature telemetry, which is highly useful to monitor the proper functioning of the implanted electronics and electrode contacts. Telemetry can also support the clinical management in young children and difficult cases where neural unresponsiveness is suspected. This article will review recent advances in the telemetry of the electrically evoked compound action potential that have made these measurements simple and routine procedures in most cases. The distribution of the electrical stimulus itself sampled by "electrical field imaging" reveals general patterns of current flow in the normal cochlea and gross abnormalities in individual patients; models have been developed to derive more subtle insights from an individual electrical field imaging. Finally, some thoughts are given to the extended application of telemetry, for example, in monitoring the neural responses or in combination with other treatments of the deaf ear

Primary perception of stimulus structure

Contains fulltext : mmubn000001_070138397.pdf (publisher's version ) (Open Access)Promotor : A. Thomassen141 p

Speech understanding in noise with an eyeglass hearing aid: asymmetric fitting and the head shadow benefit of anterior microphones.

OBJECTIVE: To test speech understanding in noise using array microphones integrated in an eyeglass device and to test if microphones placed anteriorly at the temple provide better directivity than above the pinna. DESIGN: Sentences were presented from the front and uncorrelated noise from 45, 135, 225 and 315 degrees . STUDY SAMPLE: Fifteen hearing impaired participants with a significant speech discrimination loss were included, as well as 5 normal hearing listeners. RESULTS: The device (Varibel) improved speech understanding in noise compared to most conventional directional devices with a directional benefit of 5.3 dB in the asymmetric fit mode, which was not significantly different from the bilateral fully directional mode (6.3 dB). Anterior microphones outperformed microphones at a conventional position above the pinna by 2.6 dB. CONCLUSIONS: By integrating microphones in an eyeglass frame, a long array can be used resulting in a higher directionality index and improved speech understanding in noise. An asymmetric fit did not significantly reduce performance and can be considered to increase acceptance and environmental awareness. Directional microphones at the temple seemed to profit more from the head shadow than above the pinna, better suppressing noise from behind the listener

Verbeterde overdracht van spraak met een cochleair implantaat: Waar is de flessenhals?

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Signal-to-noise ratios of the auditory steady-state response from fifty-five EEG derivations in adults.

Contains fulltext : 57890.pdf (publisher's version ) (Open Access)The Auditory Steady-State Response (ASSR) was recorded in 20 awake adults with normal hearing on ten EEG channels simultaneously to find derivations with the best signal-to-noise ratios (SNRs). Stimuli were 20% frequency modulated tones of 0.5 and 2 kHz at 20 dB SL, 100% amplitude modulated at 90 or 94 Hz, and presented one at a time to one ear. ASSR recordings using a set of at least three channels improved SNRs significantly by an average of between 6% (500 Hz right ear) to 118% (2 kHz right ear) above the SNRs from the conventional channels. Assuming that the recording time was proportional to 1/(SNR)2, this translates into a recording time of 89% (500 Hz right ear) to 21% (2 kHz right ear) of that for conventional single-channel recording. The three channels comprised the electrode positions inion, right mastoid, and left mastoid. All three electrode positions were referenced to Cz. Adding a fourth channel (Pz-Cz) increases the number of participants with significant responses from the 500 Hz right ear stimulus from 13 to 17. Electrode position F4 and other commonly used positions such as the forehead and right earlobe made significantly less contribution to test efficiency

Speech perception with mono- and quadrupolar electrode configurations: a crossover study.

OBJECTIVE: To study the effect of two multipolar electrode configurations on speech perception, pitch perception, and the intracochlear electrical field. STUDY DESIGN: Crossover design; within subject. SETTING: Tertiary referral center. PATIENTS: Eight experienced adult cochlear implant users. INTERVENTION: Each subject used each of three experimental processors for 3 weeks. The following processors were compared that differed only in electrode configuration: 1) monopolar; 2) hybrid quadrupolar, in which half of the current returned to the extracochlear reference electrode and half to two electrodes immediately to the left and right of the active electrode; and 3) flat tripolar +2, which directed all the current to four reference electrodes (two on each side), separated from the active electrode by two inactive electrodes. All the processors used the standard Advanced Bionics HiRes speech-processing strategy, 12 channels, 1,220 pulses per second per channel, and with a pulse width of 33 (micros/phase). RESULTS: The monopolar processors had the largest stimulation efficiency and the smallest dynamic range in linear current units. The reverse was true of flat tripolar +2 processor, whereas the hybrid quadrupolar processor fell in between. Insufficient loudness growth prevented the use of the flat tripolar +2 processor in three subjects. Word recognition did not differ between the clinically used 16-channel monopolar processor and the experimental monopolar processor, regardless of the differences in the number of channels, pulse rate, and duration of experience. Word recognition with the flat tripolar +2 processor was significantly poorer than with the monopolar and hybrid quadrupolar processors; monopolar and quadrupolar processors did not differ. There was no significant interaction between processor type and competing noise type (stationary or fluctuating), but performance at the higher level of fluctuating noise was best with the hybrid quadrupolar processor in almost all the subjects. Pitch scaling showed ceiling performance in five subjects and differed between processors in the two other subjects with imperfect tonotopy. Intracochlear current spread was considerable with the monopolar configuration; it was reduced with the hybrid quadrupolar configuration and virtually absent beyond the active electrodes with the tripolar configuration. CONCLUSION: More confined configurations reduced the longitudinal width of the electrical field, which was expected to enhance channel separation, but no improvement in word recognition was found. More research is needed to test confined configurations that have enhanced efficiency and to evaluate the fundamental effects of configuration on channel discriminability

Averaged electrode voltages in users of the Clarion cochlear implant device.

Item does not contain fulltextAveraged electrode voltages (AEVs) are of secondary importance for integrity testing of cochlear implant devices featuring back-telemetry. However, AEVs are device-independent and may show intermittent failures and deviant stimulation patterns unnoticed by telemetry. We collected AEVs from 18 users of the Clarion 1.2 system and 6 users of the HiFocus system in order to establish norms for evaluating AEVs in difficult cases. The stimuli were presented with the standard clinical software. Monopolar stimulation at about 16 microA showed large AEVs (mean, 173 microV) suitable for integrity testing. No electrode failures were found. The AEV amplitudes from neighboring electrodes differed by less than 30% (2 SD). The AEVs from subjects with the Clarion HiFocus electrode and/or the Clarion electrode positioner were within the normal range. The AEV amplitudes from bipolar stimulation were much more variable. Inversion of phases between electrodes was found in patients with an altered state of the cochlea (otosclerosis and osteogenesis imperfecta) and in a patient with a curled electrode tip. There was no correlation across subjects between AEVs and electrode impedances. Therefore, impedances are dominated by the electrode-tissue interface, in contrast to AEVs, which are determined by the volume conduction in the body

Electrical impedance of the cochlear implant lubricants hyaluronic acid, oxycellulose, and glycerin

Contains fulltext : 25756___.PDF (publisher's version ) (Open Access

Performance of prelingually and postlingually deaf patients using single-channel or multichannel cochlear implants

Contains fulltext : 20830___.PDF (publisher's version ) (Open Access