The management of cochlear nerve deficiency.

The assessment process is critical in deciding whether a profoundly deaf child with cochlear nerve deficiency (CND) will be suitable for a cochlear or auditory brainstem implant (ABI). Magnetic resonance imaging (MRI) using submillimetric T2 weighted gradient echo or turbo spin echo sequences is mandatory for all profoundly deaf children to diagnose CND. Evidence of audition on behavioural or electrophysiological tests following both auditory and electrical stimulation sometimes allows identification of significant auditory tissue not visible on MRI. In particular electric auditory brainstem response (EABR) testing may allow some quantification of auditory tissue and help decide whether a cochlear implant will be beneficial. Age and cognitive development are the most critical factors in determining ABI benefit. Hearing outcomes from both cochlear implants and ABIs are variable and likely to be limited in children with CND. A proportion of children will get no benefit. Usually the implants would be expected to provide recognition of environmental sounds and understanding of simple phonetics. Most children will not develop normal speech and they will often need to learn to communicate with sign language. The ABI involves a major neurosurgical procedure and at present the long term outcomes are unknown. It is therefore essential that parents who are considering this intervention have plenty of time to consider all aspects and the opportunity for in depth discussion.

Predictors of audiological outcome following cochlear implantation in adults.

The objective of this study was to examine variables that may predict open set speech discrimination following cochlear implantation. It consisted of a retrospective case review conducted in a tertiary referral centre with a cochlear implant programme. The patients were 117 postlingually deafened adult cochlear implant recipients. The main outcome measures were Bench, Kowal, Bamford (BKB) sentence scores recorded nine months following implant activation. The variables studied were age at the time of surgery, sex, duration of hearing loss, aetiology of hearing loss, residual hearing, implant type, speech processor strategy, number of active electrodes inserted. Variables found to have a significant effect on BKB following univariate analysis were entered into a multivariate analysis to determine independent predictors. Multivariate ordinal regression analysis gave an odds ration of 1.09 for each additional year of deafness prior to implantation (confidence interval 1.06-1.13; p < 0.001). Duration of deafness prior to implantation is an independent predictor of implant outcome. It accounted for 9% of the variability. Other factors must influence implant performance.

Device nonuse among adult cochlear implant recipients.

OBJECTIVE: To examine the causes and prevalence of previous and current device nonuse among adults who have received cochlear implants. STUDY DESIGN: Retrospective case review. SETTING: Adult tertiary referral center for cochlear implantation. METHODS: Two hundred fourteen consecutively implanted adult patients. The length of implant use ranged from 1 month to 14 years. MAIN OUTCOME MEASURE: A period of 4 consecutive weeks of nonuse of cochlear implant, including both obligatory and elective nonuse. RESULTS: Twenty-nine adults (13.6% of implantees) were identified as having at some stage not used their device for a period of more than 4 consecutive weeks. The main reason was device failure (n = 11). Ten adults are current nonusers (4.7% of implantees). Reasons include surgical complication necessitating explantation (n = 3), comorbid illness (n = 3), elective nonuse (n = 2), audiologic complication (n = 1), and device failure (n = 1). CONCLUSION: The overall prevalence of device nonuse was noted to increase slowly with time. The role of psychologic factors in contributing to the decision of an individual to elect to opt out of device use remains unproven.

Trends and outcomes in the Manchester adult cochlear implant series.

The adult cochlear implant programme in Manchester was established in 1988, initially using funding obtained from the HEAR (Help Ear and Allied Research: charity number: 519784) charity before government resources became available in the mid-1990s. Manchester was the first centre in the UK to implant multichannel devices on a regular basis. To date, over 250 adults have been implanted, including nine bilateral and eight deaf-blind patients. All the patients have a postlingual onset of severe-profound hearing loss; 73% (n = 175) of the implants performed used a Nucleus multichannel implant and 24% (n = 58) used a Medel multichannel implant. In addition, the team has implanted three Medel single channel devices, two Ineraid devices and one Clarion High Focus II device. This study is a retrospective analysis of the trends and outcomes in implant fitting during the first 14 years (1988-2002) of the programme. The paper describes the patient demographics and audiological complications for 240 implantations performed on 214 patients. Speech perception outcomes are reported for a subset of the patients. The average score for the Bench, Kowal, Bamford sentence test at the post-18-month stage of implant use is 66% and for Arthur Boothroyd words 53%. Trends in the series are analysed with respect to the change in criteria for adult implantation, the move towards bilateral implantation and the rate of uptake of cochlear implants by different ethnic groups.

Moderating effects of perceived control and need for clarity on the relationship between role stressors and employee affective reactions.

The authors examined the salience of perceived control and need for clarity as "buffers" of the adverse consequences of role stressors by using hierarchical regressions on role ambiguity and role conflict, with job satisfaction and psychological strain as the criterion variables. In a sample of U.S. and New Zealand employees, perceived control was directly associated with higher satisfaction and reduced strain but displayed no moderating effect on stressor-outcome relationships. Need for clarity, on the other hand, was a significant moderator of the relationship of role ambiguity and conflict to both satisfaction and strain; that finding suggests that researchers could give more attention to dispositional variables in examining the correlates of role stressors.

A comparison of methods of measuring chromatic activity in the integument of a teleost.

1. Pallor induced by noradrenalin (5 x 10(-7) mol/kg) injection of dark Pseudopleuronectes americanus was measured as increase in skin reflectance and the degree of melanosome aggregation determined. 2. Mean skin reflectance increased approximately 30% on the Munsell neutral value scale. 3. At maximal mean reflectance, melanosomes were fully aggregated in most epidermal melanophores, but displayed more variable aggregation in dermal melanophores. 4. Individual reflectance estimates did not provide consistent indications of melanosome aggregation at maximum pallor. 5. The relative merits of reflectance and cellular methods of estimating melanophore activity are discussed with particular reference to this species.

Hepatic perfusion index in cirrhotic livers--investigation of imaging and analytical procedures.

Dynamic hepatic scintigraphy was performed in a group of cirrhotic patients to evaluate the optimum imaging and analytical procedures necessary for the measurement of the hepatic perfusion index (HPI). Patients were studied in the posterior (n = 19) and the anterior (n = 14), positions, with either 0.2 or 0.5 ml of 99Tcm sulphur colloid administered as a rapid bolus injection. In each subject, three ROIs (small, medium and large) were drawn over the liver, and time-activity perfusion curves were generated. Analytical techniques were developed to allow flexibility in selecting the arterial and portal venous phases of the liver perfusion curve. The quality of the bolus, expressed as the full width at half-maximum of the left ventricular time--activity curve, was independent of the bolus volumes and patient positioning. The dispersion in the data and the inter-observer variation were less in the anterior view using medium and large ROIs, compared with the anterior small ROI and all the posterior ROI sizes. A time delay between liver and kidney arterial phases, if ignored, produced statistically significant effects on the values of the HPI. We conclude that HPI investigations are best performed in the anterior projection. Data analysis using a large liver ROI is preferred, and flexible data-processing techniques are recommended, particularly in the presence of a liver and kidney arterial time delay.

A model of the hepatic perfusion index in the rat.

The hepatic perfusion index (HPI) is an indicator of the relative hepatic arterial to total liver blood flow as measured by dynamic flow scintigraphy. Hitherto, accurate assessment of the HPI in small animals has not been possible because of methodological difficulties. A reproducible method for measuring the HPI by dynamic scintigraphy in rats is described using a rapid intraventricular bolus administration of 0.04 ml 99Tcm sulphur colloid. There was no significant difference between the HPI determined by dynamic scintigraphy and and that calculated from absolute measurements of hepatic arterial and total liver blood flow. These results indicate that the HPI derived by dynamic scintigraphy in the rat is a true estimate of the ratio of the hepatic arterial to total liver blood flow.

Positive prejudice in ethnic attitudes: Australian data.

An experiment was conducted to determine whether members of a majority ethnic group would exhibit positive prejudice in their attitudes toward an ethnic minority. Subjects were given written communications which evaluated Aborigines and white Australians either favourably or unfavourably. The occurrence of positive prejudice was assessed by examining subjects' overall agreement with each communication as a whole and their level of agreement with specific descriptions which comprised the communications. Results confirmed the existence of positive prejudice in these responses, but also indicated that subjects' reactions to the communications were influenced by the predispositional variable of ethnocentrism. The study further investigated whether positive prejudice is limited to responses illustrating minimal commitment or whether it forms a central component of inter-ethnic attitudes. Analysis of delayed recall of the specific descriptions from the written communications and of agreement with an independent ethnic attitudes questionnaire suggested that positive prejudice does not generalize beyond short-term, inconsequential reactions. The implications of these findings and the relevance of the positive prejudice concept are discussed.