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Biomedical subjects

Andrew Mackinnon

Publications and source records attributed to Andrew Mackinnon.

At least 19 recordsLinked to original sources
PubMed2007

Psychometric properties of the quality of life questionnaire for children with CP.

This paper describes the development and psychometric properties of a condition-specific quality of life instrument for children with cerebral palsy (CP QOL-Child). A sample of 205 primary caregivers of children with CP aged 4 to 12 years (mean 8y 5mo) and 53 children aged 9 to 12 years completed the CP QOL-Child. The children (112 males, 93 females) were sampled across Gross Motor Function Classification System (GMFCS) levels (Level I=18%, II=28%, III=14%, IV=11%, V=27%). Primary caregivers also completed other measures of child health (Child Health Questionnaire; CHQ), QOL (KIDSCREEN), and functioning (GMFCS). Internal consistency ranged from 0.74 to 0.92 for primary caregivers and from 0.80 to 0.90 for child self-report. For primary caregivers, 2-week test-retest reliability ranged from 0.76 to 0.89. The validity of the CP QOL is supported by the pattern of correlations between CP QOL-Child scales with the CHQ, KIDSCREEN, and GMFCS. Preliminary statistics suggest that the child self-report questionnaire has acceptable psychometric properties. The questionnaire can be freely accessed at http://www.deakin.edu.ac/hmnbs/chase/cerebralpalsy/cp_qol_home.php.

Cerebral Palsy↗
PubMed2006

Psychopathology in young people with intellectual disability.

CONTEXT: Comorbid severe mental health problems complicating intellectual disability are a common and costly public health problem. Although these problems are known to begin in early childhood, little is known of how they evolve over time or whether they continue into adulthood. OBJECTIVE: To study the course of psychopathology in a representative population of children and adolescents with intellectual disability. DESIGN, SETTING, AND PARTICIPANTS: The participants of the Australian Child to Adult Development Study, an epidemiological cohort of 578 children and adolescents recruited in 1991 from health, education, and family agencies that provided services to children with intellectual disability aged 5 to 19.5 years in 6 rural and urban census regions in Australia, were followed up for 14 years with 4 time waves of data collection. Data were obtained from 507 participants, with 84% of wave 1 (1991-1992) participants being followed up at wave 4 (2002-2003). MAIN OUTCOME MEASURES: The Developmental Behaviour Checklist (DBC), a validated measure of psychopathology in young people with intellectual disability, completed by parents or other caregivers. Changes over time in the Total Behaviour Problem Score and 5 subscale scores of the DBC scores were modeled using growth curve analysis. RESULTS: High initial levels of behavioral and emotional disturbance decreased only slowly over time, remaining high into young adulthood, declining by 1.05 per year on the DBC Total Behaviour Problem Score. Overall severity of psychopathology was similar across mild to severe ranges of intellectual disability (with mean Total Behaviour Problem Scores of approximately 44). Psychopathology decreased more in boys than girls over time (boys starting with scores 2.61 points higher at baseline and ending with scores 2.57 points lower at wave 4), and more so in participants with mild intellectual disability compared with those with severe or profound intellectual disability who diverged from having scores 0.53 points lower at study commencement increasing to a difference of 6.98 points below severely affected children by wave 4. This trend was observed in each of the subscales, except the social-relating disturbance subscale, which increased over time. Prevalence of participants meeting criteria for major psychopathology or definite psychiatric disorder decreased from 41% at wave 1 to 31% at wave 4. Few of the participants (10%) with psychopathology received mental health interventions during the study period. CONCLUSION: These results provide evidence that the problem of psychopathology comorbid with intellectual disability is both substantial and persistent and suggest the need for effective mental health interventions.

Adolescent↗
PubMed2006

The brain reserve hypothesis, brain atrophy and aging.

BACKGROUND: Researchers have used the concept of brain reserve to explain the dissociation between pathological brain damage and cognitive and functional performance. A variety of brain reserve hypotheses exist, and different empirical strategies have been employed to investigate these variants. OBJECTIVE: The study investigates (i) the relationship between measures of brain burden (atrophy, white matter hyperintensities (WMH)) and measures of reserve (education, creativity, and intelligence); (ii) the relationship between cognitive decline and reserve; (iii) whether measures of reserve mediate the effect of atrophy on estimated cognitive change, and (iv) the association between brain risk factors, education and atrophy. METHODS: A cross-sectional study of a sample of 446 individuals 60-64 years of age who underwent MRI scans as part of a large epidemiological study. Measures were taken of education, intelligence, creativity, cognitive speed, brain volume, WMH, estimated cognitive decline from earlier in life and brain atrophy. RESULTS: No association was found between estimated cognitive decline and brain burden (atrophy, WMH). Risk factors for brain insult were not associated with greater brain atrophy in the less well educated. Neither education, nor any other measure including intelligence or creativity, provided a buffer for cognitive decline in individuals with high levels of brain atrophy. CONCLUSION: Little support was found for the brain reserve hypothesis.

Aging↗
PubMed2006

Development and validation of the Beliefs and Behaviour Questionnaire (BBQ).

OBJECTIVE: To develop and validate a questionnaire to screen for potential nonadherence in patients with chronic ailments. METHODS: Themes from qualitative interviews with chronic obstructive pulmonary disease patients were used in developing content of the questionnaire. The questionnaire was distributed to 525 ambulatory patients with chronic lung diseases. Principal components analysis was performed to identify the subscales in the questionnaire. Internal consistency, validity and stability of the subscales were also evaluated. RESULTS: The 30-item Beliefs and Behaviour Questionnaire (BBQ) measures beliefs, experiences and adherent behaviour on five-point Likert-type scales. Two hundred and eighty patients (53.3%) with a mean age of 71.1 years responded to the questionnaire. The 'beliefs' section had a two-factor solution-'confidence' and 'concerns' with internal consistencies of 0.82 and 0.45, respectively. The two domains identified from the section 'experiences'-satisfaction' and 'disappointment' had internal consistencies of 0.85 and 0.52, respectively. The 'behaviour' section, separately entitled the Tool for Adherence Behaviour Screening (TABS), had a two-factor solution--'adherence' and 'nonadherence', with internal consistencies of 0.80 and 0.59, respectively. All the domains demonstrated comparable reliabilities across two different patient populations. Their temporal stabilities ranged between 0.62 and 0.94. CONCLUSION: The validity, reliability and utility of the BBQ and the TABS, a sub-scale of the BBQ that screens both intentional and unintentional nonadherence to pharmacological and non-pharmacological disease management, have been established. PRACTICE IMPLICATIONS: The BBQ and the TABS have potential applications in screening adherence beliefs, experiences and behaviour in both clinical practice and research.

Aged↗
PubMed2006

Laser-driven shock experiments on precompressed water: Implications for "icy" giant planets.

Laser-driven shock compression of samples precompressed to 1 GPa produces high-pressure-temperature conditions inducing two significant changes in the optical properties of water: the onset of opacity followed by enhanced reflectivity in the initially transparent water. The onset of reflectivity at infrared wavelengths can be interpreted as a semiconductor<-->electronic conductor transition in water, and is found at pressures above approximately 130 GPa for single-shocked samples precompressed to 1 GPa. Our results indicate that conductivity in the deep interior of "icy" giant planets is greater than realized previously because of an additional contribution from electrons.

Journal Article↗
PubMed2006

Paediatric quality of life instruments: a review of the impact of the conceptual framework on outcomes.

With an increasing number of paediatric quality of life (QOL) instruments being developed, it is becoming difficult for researchers and clinicians to select the most appropriate instrument. Reviews of QOL instruments tend to report only basic properties of the instruments such as domains and psychometric properties. This paper seeks to appraise critically the conceptual underpinnings of paediatric QOL instruments. A systematic review was conducted to identify QOL instruments for children aged 0 to 12 years, and to examine and compare their conceptual frameworks, definitions employed, and structure. Both generic and condition-specific measures were reviewed. Fourteen generic and 25 condition-specific QOL instruments were identified. Eleven types of definition of QOL and health-related QOL and three theories of QOL were identified. QOL was measured by a variety of domains including emotional, social and physical health, and well-being. Items commonly assessed difficulties, or intensity/frequency of feelings/symptoms, in contrast to positive aspects of life and happiness. The findings highlight the diversity that is apparent in the conceptualization of paediatric QOL and draw attention to the lack of empirical evidence for many of the fundamental assumptions. The impact of the conceptual underpinnings of the instruments on the resulting QOL scores is discussed.

Affect↗
PubMed2006

Effects on parental mental health of an education and skills training program for parents of young children with autism: a randomized controlled trial.

OBJECTIVE: To determine the impact of a parent education and behavior management intervention (PEBM) on the mental health and adjustment of parents with preschool children with autism. METHOD: A randomized, group-comparison design involving a parent education and counseling intervention to control for nonspecific therapist effects and a control sample was used. Two metropolitan and two rural regions were randomly allocated to intervention groups (n = 70) or control (n = 35). The parents of consecutive children with autism (2(1/2)-5 years old) from the autism assessment services for the intervention regions were then randomly allocated to either a 20-week manual-based parent education and behavior management intervention (n = 35) or a manual-based parent education and counseling intervention (n = 35). The main outcome measure of parental mental health was the General Health Questionnaire used pre- and postintervention and at 6-month follow-up. RESULTS: Both treatments resulted in significant and progressive improvement in overall mental health at follow-up (F = 2, 97, p =.007) and mental health significantly improved over time in the 54% of principal caregivers who had the highest levels of mental health problems. The parent education and behavior management intervention was effective in alleviating a greater percentage of anxiety, insomnia, and somatic symptoms and family dysfunction than parent education and counseling at 6-month follow-up. CONCLUSIONS: A 20-week parent education and skills training program for parents of young children newly diagnosed with autism provides significant improvements in parental mental health and adjustment, justifying its addition to early intervention programs at least for parents with mental health problems.

Adaptation, Psychological↗
PubMed2006

An instrument to measure engagement in life: factor analysis and associations with sociodemographic, health and cognition measures.

BACKGROUND: It has been proposed that active engagement with life may protect against cognitive decline. However, existing instruments for measuring life engagement have covered limited domains. OBJECTIVE: To present a new instrument to measure engagement with life; the RIASEC Activities List draws on activities categorised according to interest categories previously developed by Holland: Realistic, Investigative, Artistic, Social, Enterprising and Conventional (RIASEC). METHODS: Participants in a longitudinal, community-based survey were drawn from 3 age groups: 2,404 participants aged 20-24; 2,530 aged 40-44, and 2,551 aged 60-64 years. They provided information on which of 54 selected activities they had performed in the 6 months prior to their survey interview. Other information obtained from participants included measures of sociodemographic characteristics, personality attributes and mental and physical health. Two measures of cognition were also examined. Analyses were conducted separately for men and women in each of the 3 age groups. RESULTS: Confirmatory factor analyses identified six scales of activity types corresponding to Holland's six interest categories. The number of activities of any type undertaken in the past 6 months was significantly associated with cognitive measures, better physical health, and better mental health although these findings varied for men and women across the 3 age groups. Further, for both men and women in all age groups, performing activities of any type was associated with having higher extraversion and mastery scores, and lower levels of neuroticism. Associations were also found between performing specific types of activities and cognitive measures. CONCLUSIONS: This instrument has the potential to identify more clearly types of activities that may offer cognitive benefits and warrants further testing in longitudinal studies.

Adult↗
PubMed2006

Search for a common cause factor amongst cognitive, speed and biological variables using narrow age cohorts.

BACKGROUND: Cross-sectional studies have demonstrated that age-related effects on many cognitive and biological functioning variables are shared. A number of theories postulate that these associations arise from a common causal mechanism responsible for change across a wide range of functions. However, it has been claimed that the finding of shared variance among variables in these studies may be spurious because most studies have been cross-sectional and based on age-heterogeneous samples. OBJECTIVE: To examine evidence for changes with age in variance shared by cognitive variables using a narrow-age cohort design. METHODS: Three samples of adults with age ranges 20-24 years (n = 2,404), 40-44 years (n = 2,530) and 60-64 years (n = 2,510) were drawn from a population-based study. These groups were supplemented by data from an older sample of individuals (77 years and over) from a second population-based study (n = 374). Four models of the structure of a range of cognitive, speed and biological variables derived from previous cross-sectional research were fitted to data. These models were complete independence of variables within a cohort, a single common factor, multiple independent factors, and a second order factor model. RESULTS: Model fit and the magnitude of loadings from multiple-group confirmatory factor analyses was compared between age groups. The fit for all four models was worse in the 60-64 year age group. Factor loadings on the common factor specified in these models varied between the groups, but the speed factor rather than the biological factor showed increased loadings as a function of age. CONCLUSIONS: This narrow age-cohort study did not support the existence of developmental changes in the structure of cognitive and biological variables across the lifespan. Shared variation between measures of cognition and biological function may be an artifact of the research designs that have generated these findings. This casts doubt of the existence of a common causal mechanism. However, it may be that such changes manifest only in later old age.

Adult↗
PubMed2005

Structure of beliefs about the helpfulness of interventions for depression and schizophrenia. Results from a national survey of the Australian public.

BACKGROUND: The public tends to have different views from professionals about the treatment of mental disorders. It has been proposed that these differences do not simply reflect a lack of knowledge about treatments, but also the operation of pre-existing general belief systems about health interventions. The present study uses factor analysis to examine the structure of public beliefs about interventions for depression and schizophrenia, using case vignettes that vary in severity or stage of illness. METHODS: In a national survey of 3,998 Australian adults, respondents were presented with one of four vignettes: depression, depression with suicidal thoughts, early schizophrenia and chronic schizophrenia. Respondents were asked about the likely helpfulness or harmfulness of a wide range of interventions for the person in the vignette. Methods suitable for ordinal data were used to explore a range of factor analytic solutions. Once identified, the location of participants on each factor was estimated by calculating a mean score for items loading highly on that factor. These scale means were compared between subgroups of participants. RESULTS: Four factors were found. Three of these-Lifestyle, Psychological and Medical-corresponded to previously found factors. An additional factor named Information-seeking was defined by items that had not been included in earlier research. These items concerned obtaining information or advice from a variety of sources including the internet, books and health educators. Differences on the factors were a function of socio-demographic factors and ability to identify the condition portrayed in the vignette. However, the magnitude of these differences was small. Differences between factors were more pronounced, with mean ratings on the Medical factor falling between harmful and neutral, while mean ratings on other factors lay between neutral and helpful. CONCLUSION: The public tends to favour psychological and lifestyle interventions over medical ones. These beliefs do not reflect specific knowledge about the effectiveness of particular treatments, but rather general commitments to broad classes of treatment that are applied irrespective of the type of mental disorder. Educational campaigns to improve public knowledge about treatments will need to take account of these pre-existing belief systems.

Adult↗
PubMed2004

Direct experimental evidence of back-surface ion acceleration from laser-irradiated gold foils.

Au foils were irradiated with a 100-TW, 100-fs laser at intensities greater than 10(20) W/cm2 producing proton beams with a total yield of approximately 10(11) and maximum proton energy of >9 MeV. Removing contamination from the back surface of Au foils with an Ar-ion sputter gun reduced the total yield of accelerated protons to less than 1% of the yield observed without removing contamination. Removing contamination from the front surface (laser-interaction side) of the target had no observable effect on the proton beam. We present a one-dimensional particle-in-cell simulation that models the experiment. Both experimental and simulation results are consistent with the back-surface acceleration mechanism described in the text.

Journal Article↗
PubMed2004

A National Depression Index for Australia.

OBJECTIVE: To develop a National Depression Index for measuring the depression status of the Australian population. DESIGN: Cross-sectional data were analysed from two random samples of the Australian adult population - the National Survey of Mental Health and Wellbeing (2000) and the National Health Survey (2001). PARTICIPANTS: The National Survey of Mental Health and Wellbeing (2000) - 10 641 participants; and the National Health Survey (2001) - 17 918 participants. MAIN OUTCOME MEASURES: Selected items from the Kessler Psychological Distress Scale (K10); and diagnoses of a major depressive episode according to DSM-IV criteria using a computerised interview. RESULTS: Six items from the K10 that were most closely related to the DSM-IV diagnosis of "major depressive episode" were identified. Scores on an index calculated from these items were rescaled to form an index reflecting relative risk of depression and having a value of 100 for the Australian adult population. Taking into account sex, employment status and income, index values were higher in younger people, females, unemployed people and those socioeconomically disadvantaged. This pattern provides additional support for the validity of the index, as well as establishing benchmark levels to which index values from future surveys and in other groups may be compared. CONCLUSIONS: The proposed National Depression Index is a valid indicator of depression and level of depressive symptoms. It is suitable for monitoring depression at the population level. The scaling characteristics of the measure ensure that it can be interpreted by members of the general public.

Adolescent↗
PubMed2004

On the non-significance of internal versus external auditory hallucinations.

Traditionally, auditory hallucinations (AHs) heard outside the head have been regarded as more pathological than those heard inside, partly on the basis that internal AHs are conceptually closer to normal thinking than external AHs. Our data show that many patients hear AHs both internally and externally, and there were very few associations between location and demographic and clinical characteristics of the patients or with other characteristics of the AHs themselves. There was evidence that AHs heard internally were associated with better insight than those heard externally. Of those patients whose AHs included commands, greater proportions of those who heard them externally said they could resist than those who heard them internally or in both locations. There appears to be no consistent differential impact and effect of internal and external AHs, and there was no support for the historical view that internal AHs are more benign.

Adolescent↗
PubMed2004

Correlates of the affective impact of auditory hallucinations in psychotic disorders.

While many who hear auditory hallucinations (AHs) experience them as unpleasant, some do not. Little is known about the correlates of AHs that are not unpleasant, or of the characteristics of those who hear them. To better understand this symptom, we used a comprehensive structured interview schedule to study 199 subjects who had experienced AHs. Subjects' responses to AHs were combined into two indexes: one assessing total affective impact and the other assessing the affective direction (positive or negative). Subjects who had grandiose delusions experienced their AHs more positively. AHs that were more frequent, lasted longer, and were louder were experienced more negatively. AHs heard in the second person and those related to people with whom the subjects had personal relationships were more positive than those heard in the third person. Many other aspects of AHs were unrelated to total affective impact or direction. It is argued that the positive evaluation of voices by subjects requires greater attention than it has received previously. Implications for assessment, clinical practice, and research are discussed.

Adolescent↗
PubMed2004

Factors associated with compliance and resistance to command hallucinations.

Command hallucinations (CHs) are hallucinations that direct the patient to perform an action. Beyond issues related to the danger that some CHs may pose, comparatively little is known about the broader clinical context of CHs. To investigate this, 199 patients were interviewed using the Mental Health Research Institute Unusual Perceptions Scale. More than two thirds of the sample reported hearing CHs. A quarter of these patients felt unable to resist them. Patients with CHs reported their voices more negatively than those who did not hear commands. More of those unable to resist CHs rated their hallucinations as intrusive, they had fewer coping strategies than those able to resist, and they were prescribed higher dosages of medication. CHs are associated with a greater degree of adverse hallucinatory and illness experience. Patients who experience CHs may have a more malignant form of the underlying disorder. Thus, CHs warrant special therapeutic attention for reasons beyond any harm that their commands pose to themselves or others.

Adaptation, Psychological↗
PubMed2003

Metal-protein attenuation with iodochlorhydroxyquin (clioquinol) targeting Abeta amyloid deposition and toxicity in Alzheimer disease: a pilot phase 2 clinical trial.

BACKGROUND: Alzheimer disease (AD) may be caused by the toxic accumulation of beta-amyloid (Abeta). OBJECTIVE: To test this theory, we developed a clinical intervention using clioquinol, a metal-protein-attenuating compound (MPAC) that inhibits zinc and copper ions from binding to Abeta, thereby promoting Abeta dissolution and diminishing its toxic properties. METHODS: A pilot phase 2 clinical trial in patients with moderately severe Alzheimer disease. RESULTS: Thirty-six subjects were randomized. The effect of treatment was significant in the more severely affected group (baseline cognitive subscale score of the Alzheimer's Disease Assessment Scale, >/=25), due to a substantial worsening of scores in those taking placebo compared with minimal deterioration for the clioquinol group. Plasma Abeta42 levels declined in the clioquinol group and increased in the placebo group. Plasma zinc levels rose in the clioquinol-treated group. The drug was well tolerated. CONCLUSION: Subject to the usual caveats inherent in studies with small sample size, this pilot phase 2 study supports further investigation of this novel treatment strategy using a metal-protein-attenuating compound.

Aged↗
PubMed2003

Improving screening accuracy for dementia in a community sample by augmenting cognitive testing with informant report.

This study sought to determine whether the augmentation of cognitive testing with an informant report questionnaire could improve accuracy in screening for dementia in a community setting. The sample consisted of 646 subjects aged 70-93 years. Cognitive state was assessed using the Mini-Mental State Examination (MMSE). Informants completed the 16-item short form of the Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE). Dementia was diagnosed according to DSM-III-R criteria. Combination of the IQCODE with the MMSE resulted in more accurate prediction of caseness than either test alone. Receiver Operating Characteristic analysis demonstrated the superior screening performance of a logical "or" rule and a weighted sum of scores on the two tests over other methods of combination, replicating previous clinically based research. The findings also suggest that the appropriate combination of existing tests may be a fruitful method of improving screening accuracy in a variety of situations.

Aged↗