Aboriginal perspective on middle ear disease in the arid zone of Western Australia

OBJECTIVES

To explore perceptions, knowledge and experience of otitis media (OM) and barriers to compliance with treatment among Aboriginal people of the Kalgoorlie-Boulder area, Western Australia.

METHODS

This qualitative applied research study is based on a holistic design. We conducted structured interviews with three community focus groups, 56 key informants, and 22 mothers of babies known to have suffered from OM. Written records of interviews were checked with participants. The three sources of data enabled comparison and verification of results.

RESULTS

People were concerned about serious consequences of OM, especially deafness and learning difficulties. Since early disease may have no localizing symptoms, not surprisingly, people had limited understanding of the aetiology of OM and were often only aware of disease once ear discharge was visible. Nevertheless, they usually sought treatment for non-specific symptoms. Competing demands in people's daily lives and the unpleasant, intensive nature of treatment result in families becoming resigned to a child's chronic ear discharge. Someone other than the biological mother within the extended family may be responsible for administering treatments. Half the carers thought passive smoking may predispose children to OM and 70% suggested clearing the nasal passages to prevent OM. Results of surgery were viewed positively but specialist services were not always readily accessible.

CONCLUSIONS

Since responsibility for treatment may not lie with the biological mother, awareness campaigns must target the entire community. As early OM may be asymptomatic, health personnel should be encouraged to do otoscopy on all children with non-specific symptoms.

Immunologic and Osteogeneic Properties of Xenogeneic and Allogeneic Demineralized Bone Transplants

Xenografting is increasingly being developed as a response to the shortage of human tissues. However, antigenic components of bone material eliciting immune responses--particularly of cellular nature--are blamed for the reduction of the osteoinductive properties of bone and bone-derived implants. The aim of our study was to compare the immunologic response and osteogenesis induced by antigen-depleted allogeneic and xenogeneic bone-derived implants to that induced by partially antigen-depleted material heterotopically placed (muscular pouch) in rats. Wistar rats received bone-derived implants of different antigeneic condition, from both xenogeneic (rabbit) and allogeneic (rat) origin. After sacrifice, animals were evaluated for osteogenesis and immune response. New bone formation was observed around all bone-derived implants, whether fully or partially antigen-extracted, and from both xenogeneic and allogeneic origin. No significant humoral response resulted following bone implantation. Cellular response showed a similar pattern in partial and fully antigen-extracted bone of both allogeneic and xenogeneic origin. Xenogeneic antigen-extracted bone from safe donor sources could be a suitable solution to human tissue shortage in a near future.

Can psychological models bridge the gap between clinical guidelines and clinicians' behaviour? A randomised controlled trial of an intervention to influence dentists' intention to implement evidence-based practice

OBJECTIVE

The lag between publication of evidence for clinical practice and implementation by clinicians may be decades. Research using psychological models demonstrates that changing intention is very important in changing behaviour. This study examined an intervention (rehearsing alternative actions) to change dentists' intention to implement evidence-based practice (EBP) for third molar (TM) management.

DESIGN

Randomised controlled trial / postal.

SETTING

Primary care.

SUBJECTS AND METHODS

Dentists were randomly selected from the Scottish Dental Practice Board Register, then randomly allocated to intervention or control groups, and sent a questionnaire. The intervention group listed management alternatives to TM extraction prior to their TM extraction intention, and the control group did not. Based on psychological models for reducing a behaviour's frequency (EBP is weighted against TM extraction), prior listing of alternatives should decrease extraction intention.

MAIN OUTCOME MEASURES

Intention to extract TMs.

RESULTS

A total of 99 dentists - 70 Males, 29 Females; mean age = 41.42 years (SD = 8.62) participated in the study. The intervention significantly influenced intention to extract TMs, as desired. Despite similar background and knowledge of management alternatives, participants in the intervention group had significantly lower intention to extract: control group mean (SD) = 0.39 (1.99); intervention group mean (SD) = -0.78 (1.89); mean difference (SE) = 1.17 (0.42); 95% confidence interval for the difference = 0.34 to 1.99.

CONCLUSION

Results suggest this intervention, which successfully influenced a proximal predictor of behaviour pertinent to dental EBP, may result in improved EBP in a service-level trial. Basing implementation interventions and trial methodology on psychological models may effectively bridge the gap between clinical guidelines and practice.

Risk of hepatitis C virus transmission from patients to surgeons: model based on an unlinked anonymous study of hepatitis C virus prevalence in hospital patients in Glasgow

BACKGROUND

The risk of a surgeon acquiring the hepatitis C virus (HCV) through occupational exposure is dependent on the prevalence of HCV infection in the patient population, the probability of a percutaneous injury transmitting HCV, and the incidence of percutaneous injury during surgery.

AIMS

To estimate the prevalence of HCV infection in the adult surgical patient population in North Glasgow and thereafter estimate the risk of HCV transmission to surgeons through occupational exposure.

METHODS

The prevalence of HCV infection was estimated through the unlinked anonymous testing of samples from male surgical patients, aged 16-49 years, in two North Glasgow hospitals from 1996 to 1997, and adjusting these data for age and sex. Using published estimates of the incidence of percutaneous injury during surgery and percutaneous injury transmitting HCV, the risk of occupational transmission of HCV to surgeons was then derived.

RESULTS

The estimated prevalence of anti-HCV infection for all adult patients in the two hospitals combined was 1.4% (cardiothoracic/cardiology 0.8%, orthopaedics/rheumatology 1.4%, general surgery/ENT 2.0%). The estimated probability of HCV transmission from an HCV infected patient to an uninfected surgeon was 0.001-0.032% per annum (0.035-1.12% risk over a 35 year professional career).

CONCLUSIONS

The risk of an individual surgeon acquiring HCV through occupational exposure is low, even in an area with an extremely high prevalence of HCV among its injecting drug using population. Surgeons however should be encouraged to observe universal precautions and present for assessment after needlestick injuries to protect themselves and their patients from this insidious infection.

A study of linkage and association of body mass index in the Old Order Amish

Obesity is thought to have a genetic component with the estimates of heritability ranging from 0.25-0.40. As part of an ongoing study of obesity in the Old Order Amish, seven two- and three-generation families (157 individuals) were assessed for 21 traits related to obesity, including body mass index (BMI) and BMI-percentile (a standardized distribution of BMI adjusted for age and sex). Genotyping was performed using a panel of 384 short-tandem repeat markers. In this sample, the estimates of heritability ranged from 0.16-0.31 for BMI and from 0.40-0.52 for BMI-percentile. Model-independent linkage analysis identified candidate regions on chromosomes 1, 5, 7, 8, and 11. Given that several markers on 7q were significant for both BMI and BMI-percentile (P < or = 0.001) and that the structural locus for leptin was located on 7q, this region was considered to be the primary candidate region. Subsequent typing of additional flanking markers on 7q corroborated the original findings. Tests of intrafamilial association for alleles at markers in this candidate region were significant at similar levels. Although there is some evidence for linkage and association in the region containing leptin, there appears to be stronger evidence for linkage (P < or = 0.001) and association (P < or = 0.00001) with BMI in a region 10-15 cM further downstream of leptin, flanked by markers D7S1804 and D7S3070 with peak values from D7S495-D7S1798. Evidence from linkage and association studies suggests that this region (D7S1804-D7S3070) may be responsible, at least in part, for variation in BMI and BMI-percentile in the Old Order Amish.

Modulated cortical control of individual fingers in experienced musicians: an EEG study. Electroencephalographic study

OBJECTIVE

The present research was designed to address the nature of interdependency between fingers during force production tasks in subjects with varying experience in performing independent finger manipulation. Specifically, behavioral and electroencephalographic (EEG) measures associated with controllability of the most enslaved (ring) and the least enslaved (index) fingers was examined in musicians and non-musicians.

METHODS

Six piano players and 6 age-matched control subjects performed a series of isometric force production tasks with the index and ring fingers. Subjects produced 3 different force levels with either their index or ring fingers. We measured the isometric force output produced by all 4 fingers (index, ring, middle and little), including both ramp and static phases of force production. We applied time-domain averaging of EEG single trials in order to extract 4 components of the movement-related cortical potentials (MRCP) preceding and accompanying force responses.

RESULTS

Three behavioral findings were observed. First, musicians were more accurate than non-musicians at reaching the desired force level. Second, musicians showed less enslaving as compared to non-musicians. And third, the amount of enslaving increased with the increment of nominal force levels regardless of whether the index or ring finger was used as the master finger. In terms of EEG measures, we found differences between tasks performed with the index and ring fingers in non-musicians. For musicians, we found larger MRCP amplitudes at most electrode sites for the ring finger.

CONCLUSIONS

Our data extends previous enslaving research and suggest an important role for previous experience in terms of the independent use of the fingers. Given that a variety of previous work has shown finger independence to be reflected in cortical representation in the brain and our findings of MRCP amplitude associated with greater independence of fingers in musicians, this suggests that what has been considered to be stable constraints in terms of finger movements can be modulated by experience.

SIGNIFICANCE

This work supports the idea that experience is associated with changes in behavioral and EEG correlates of task performance and may have clinical implications in disorders such as stroke or focal hand dystonia. Practice-related procedures offer useful approaches to rehabilitation strategies.

The role of sub-maximal force production in the enslaving phenomenon

When individuals perform a force task involving only one finger, they involuntarily move other fingers as well. This phenomenon is referred to as the enslaving force or the interdependency of fingers. Given that previous literature on the enslaving force has focused on maximal isometric force production, the present research was designed to study the role of sub-maximal force production in the enslaving phenomenon. To this end, we examined behaviorally three levels of force production with a constant rate of force development. We also examined the temporal organization of enslaving separating the achievement of the desired force (ramp phase) and its maintenance (static phase). During the static phase we found: (i) the amount of enslaving increased with the increment of nominal force level whether the index, middle, ring or little fingers were used as the master finger; (ii) enslaving is strongest in the finger directly adjacent to the master finger; and (iii) in terms of enslaving, the index finger was more 'independent' than the other three fingers, regardless of nominal force produced, followed by the little, middle, and ring fingers. In terms of temporal organization, we found that the time-lag of activation of 'slave fingers' during the ramp phase was reduced as the amount of force level increased. Overall, our data suggest that enslaving effect is a task specific phenomenon and depends on the amount of force produced by the master finger.

Motor-related cortical potentials accompanying enslaving effect in single versus combination of fingers force production tasks

OBJECTIVES

This study examined behavioral indices and motor-related cortical potentials (MRCP) of the enslaving phenomenon (i.e. interdependency of finger movement) during isometric force production tasks using each of the four fingers separately and in combination. We examined MRCP preceding force production and those during the achievement of the desired force (ramp phase) and its maintenance (static phase).

METHODS

Our experimental design systematically controlled the isometric force output, including both ramp and static phases of force production. We applied time-domain averaging of electroencephalographic single trials in order to extract 3 components of MRCP (Bereitshaftspotential, motor potentials, and motor monitoring potentials) preceding and accompanying force responses.

RESULTS

We report two major findings. First, we found the index finger to be more independent, accurate, and to display the larger MRCP amplitude whereas the ring finger was more dependent, less accurate, and displayed smaller MRCP amplitude. Second, adding the neighboring finger when the ring finger produced the task significantly reduced its dependency on uninvolved fingers and increased the accuracy of both ramp and static phases which was not the case with the index finger. The amplitude of MRCP was increased when the ring finger produced the task in combination as compared to when the ring finger performed the task in isolation. In contrast, the amplitude of MRCP was significantly reduced when the index finger produced the task in combination with other fingers when compared to when the index finger performed the task in isolation.

CONCLUSIONS

Overall, the amount of the fingers' dependency on the uninvolved fingers (e.g. amount of enslaving) during isometric force production tasks was inversely related with the amplitude of MRCP indicating the contribution of central mechanisms to the enslaving phenomenon.

Movement-related EEG potentials are force or end-effector dependent: evidence from a multi-finger experiment

OBJECTIVES

This study examined behavioral and electrocortical responses in producing 3 levels of force (25, 50 and 75% of MVC) at a constant rate of force development with each of 4 fingers both during the achievement of the desired force (ramp phase) and its maintenance (static phase). We were particularly interested in describing in more detail the interaction between nominal force and finger on various components of movement-related potential (MRP) associated with preparation and execution of isometric force production tasks.

METHODS

Our experimental design systematically controlled the rate of force development while nominal force level was experimentally manipulated during isometric force production tasks. We applied time-domain averaging of EEG single trials in order to extract 3 components of MRP (BP(-600 to -500); MP(-100 to 0); MMP) preceding and accompanying behavioral responses.

RESULTS

Overall, as in our previous research the effect of force per se was not reflected in the EEG components. However, we did find an interaction between finger and force level in both the Bereitshaftspotential (BP) and motor potential (MP) components of the movement-related potentials. While the middle, ring and little finger produced no differences in EEG components at any of the 3 force levels, the index finger did. We further correlated the force trajectory and the EEG time series with the highest correlations found in the lowest force level with the index finger. As the force level was increased, the correlation was significantly reduced.

CONCLUSIONS

Overall, the whole complex of MRP components and evolution of EEG time series during multi-finger isometric force production tasks reflect a combination of factors including the primary end-effector performing the task and interaction of end-effector and the amount of nominal force.