HIV-associated neurocognitive disorders: antiretroviral regimen, central nervous system penetration effectiveness, and cognitive outcomes.

BACKGROUND: The human immunodeficiency virus (HIV) can give rise to a spectrum of neuropsychological impairments known collectively as HIV-associated neurocognitive disorders (HAND). Although antiretroviral therapy (ART) has reduced the incidence of HIV dementia, the prevalence of milder forms of HAND has increased. It has been postulated that incomplete central nervous system (CNS) viral suppression or potential drug toxicity, both of which could be related to the CNS penetration effectiveness (CPE) of ART regimens, may contribute to this phenomenon. OBJECTIVE: This study compared cognitive outcomes in clade C-infected HIV patients in South Africa treated for 1 year with ART regimens with differing CPE scores. METHODS: We assessed 111 HIV-positive patients with varying levels of cognitive function at baseline (pre-ART) and then a year later. A neuropsychological battery was administered at both visits to derive global deficit scores. ART regimen data were collected at the follow-up visit. Some participants remained ART-naïve during this period, thus providing a non-treatment control group. RESULTS: Significantly more ART recipients maintained or improved cognitive function compared with patients not on ART (p=0.017). There was no significant difference in cognitive outcomes between higher and lower CPE regimen groups (p=0.473). CONCLUSIONS: ART preserves or improves cognition in HIV-infected patients after 1 year, irrespective of the regimen's CPE. South Africa's current low CPE-scored first-line regimen performed as well as higher CPE-scored regimens. These findings are reassuring for South Africa, but larger, longer-term studies would be more definitive.

Profile of the dental therapy graduate at the University of KwaZulu-Natal.

INTRODUCTION: Dental Therapists were introduced to the oral health team of South Africa in the 1970s by the Department of Health in order to assist in reducing inequities in oral health service provision to disadvantaged communities. Training occurred at two historically disadvantaged universities viz. Medical University of Southern Africa (MEDUNSA) and the University of Durban-Westville (UDW). However, disparities in access to basic oral healthcare have continued, in contrast to the success of similar initiatives recorded by over fifty countries around the world. In 2006, the Department of Health recommended that, as Dental Therapists were critical to the provision of primary oral healthcare, their training must be offered by all dental schools. Further, the recommendation proposed that the number trained annually should be increased from 25 (in 2005) to 600 by 2009. In response, concern was expressed by the stakeholders such as the South African Dental Association (SADA) and the Committee of Dental Deans. The SADA position paper on dental therapy called for an immediate moratorium on the training of Dental Therapists until all stakeholders had debated these issues. It is clear that the issue has not been resolved and that additional data pertinent to the training and deployment of this echelon of oral healthcare workers is required. PURPOSE: The purpose of this study was to critically evaluate the application, enrolment and graduate profiles of the dental therapy classes and graduates over the period from 2001 to 2010 from the University of KwaZulu-Natal (UKZN), in order to provide baseline data for a larger study which is being conducted by the researcher on the role of the dental therapist in the healthcare system of South Africa. METHODOLOGY: Quantitative data was obtained from the Data Management Information system of UKZN on application, enrolment and graduate profiles. Data was analyzed using the Statistical Package for Social Sciences (SPSS) and Excel software. Basic measures of description such as tables, graphs and percentages were displayed. RESULTS: The applicant profile showed an exponential increase in number from 460 in 2001to 3 845 in 2010. The enrolment profile showed a linear increase from 8 in 1980 to 81 in 2010. The enrolments showed a preponderance of females, whilst all students on entrance were under 20 years of age. The racial breakdown revealed that up to 2007, more Indians than Africans were enrolled. After 2007, this trend was reversed. The graduate profile showed an upward shift around a mean of 16 graduates per year. Practice patterns showed that 47% of graduates worked in private practice, 19% went on to study dentistry, 10% worked in the public sector, 7% no longer worked in the dental profession. Nearly one fifth (16%) could not be traced. DISCUSSION AND CONCLUSION: Conflicting reports and opinions on the dental therapy profession exist among major stakeholders such as the Department of Health, the South African Dental Association and the Committee of Dental Deans. Before any decisions are made on the training of extended numbers of Dental Therapists, it is important to compile a comprehensive profile of the dental therapy graduate which will assist all the relevant stakeholders to make informed decisions about this profession.

Olfactory impairment is more marked in patients with mild dementia with Lewy bodies than those with mild Alzheimer disease.

BACKGROUND: Dementia patients with anosmia are more likely to have Lewy body pathology at postmortem, but clinicopathological studies have only assessed olfaction in moderate dementia or an average of 5 years before death. It is not known whether, in patients with mild dementia (MMSE score over 20), olfactory function is more impaired in Alzheimer disease (AD) than dementia with Lewy bodies (DLB). METHODS: Patients with mild DLB (n = 21), mild AD (n = 27), mild cognitive impairment (MCI) (n = 21) and controls (n = 47) were assessed using a 16-item olfactory identification test and an olfactory threshold test which used sticks impregnated with differing concentrations of butanol. RESULTS: Patients with mild DLB had impaired olfactory identification ability compared with those with mild AD or MCI, independent of age, cognitive function and sex. The sensitivity of a cutoff score of seven correct responses out of 16 was 0.81 for distinguishing mild DLB from mild AD (AUC 0.682). The specificity, positive predictive value and negative predictive value for the same cut-off score were 0.41, 0.48 and 0.73, respectively. The olfactory threshold was not different in the AD and DLB groups. CONCLUSIONS: Simple bedside tests of olfactory identification merit further examination for their potential to improve the identification of patients with DLB when used alongside existing criteria. They are insufficiently specific for use in screening.

Levels of CSF prostaglandin E2, cognitive decline, and survival in Alzheimer's disease.

BACKGROUND: Although epidemiological, clinical, and experimental evidence indicates that the inducible isoform of cyclo-oxygenase (COX-2) may be involved in the pathogenesis of several neurodegenerative disorders, the mechanisms whereby COX-2 contributes to Alzheimer's disease are largely unknown. OBJECTIVE: To undertake a longitudinal study of CSF levels of a major product of COX activity, prostaglandin E2 (PGE2), in relation to cognitive decline and survival in patients with Alzheimer's disease. METHODS: CSF PGE2 was measured on at least three annual visits in 35 controls and 33 Alzheimer patients (26 necropsy confirmed) who completed the Cambridge cognitive assessment (CAMCOG). RESULTS: Compared with controls, CSF PGE2 was higher in patients with mild memory impairment, but lower in those with more advanced Alzheimer's disease. The median survival time of patients with higher initial PGE2 levels was five years longer than those with lower levels. CONCLUSIONS: COX activity in Alzheimer's disease varies with stage of the disease. PGE2 levels correlate positively with patient survival. These findings suggest that inhibition of COX activity does not represent a major target for the pharmacological treatment of Alzheimer's disease.

Low free testosterone is an independent risk factor for Alzheimer's disease.

The purpose of this study was to assess pituitary gonadotropins and free testosterone levels in a larger cohort of men with Alzheimer's disease (AD, n=112) and age-matched controls (n=98) from the Oxford Project to Investigate Memory and Ageing (OPTIMA). We measured gonadotropins (follicle stimulating hormone, FSH, and luteinizing hormone, LH), sex hormone binding globulin (SHBG, which determines the amount of free testosterone) and total testosterone (TT) using enzyme immunoassays. AD cases had significantly higher LH and FSH and lower free testosterone levels. LH, FSH and SHBG all increased with age, while free testosterone decreased. Low free testosterone was an independent predictor for AD. Its variance was overall explained by high SHBG, low TT, high LH, an older age and low body mass index (BMI). In controls, low thyroid stimulating hormone levels were also associated with low free testosterone. Elderly AD cases had raised levels of gonadotropins. This response may be an attempt to normalize low free testosterone levels. In non-demented participants, subclinical hyperthyroid disease (a risk factor for AD) which can result in higher SHBG levels, was associated with low free testosterone. Lowering SHBG and/or screening for subclinical thyroid disease may prevent cognitive decline and/or wasting in men at risk for AD.

Synergy between the C2 allele of transferrin and the C282Y allele of the haemochromatosis gene (HFE) as risk factors for developing Alzheimer's disease.

BACKGROUND: There is evidence that iron may play a role in the pathology of Alzheimer's disease (AD). There may be genetic factors that contribute to iron deposition resulting in tissue damage thus exacerbating AD. METHODS: We have genotyped 269 healthy elderly controls, 191 cases with definite or probable AD, and 69 with mild cognitive impairment (MCI) from the OPTIMA cohort. RESULTS: We have examined the interaction between the C2 variant of the transferrin (TF) gene and the C282Y allele of the haemochromatosis (HFE) gene as risk factors for developing AD. Our results showed that each of the two variants was associated with an increased risk of AD only in the presence of the other. Neither allele alone had any effect. Carriers of both variants were at 5 times greater risk of AD compared with all others. The interaction was significant by logistic regression (p = 0.014) and by synergy factor analysis (p = 0.015, synergy factor = 5.1). Further, carriers of these two alleles plus apolipoprotein E epsilon4 (APOE4) were at still higher risk of AD: of the 14 tri-carriers of the three variants, identified in this study, 12 had AD and two MCI. CONCLUSION: We suggest that the combination of TF C2 and HFE C282Y may lead to an excess of redox-active iron and the induction of oxidative stress in neurones, which is exacerbated in carriers of APOE4. Since 4% of Northern Europeans carry the two iron-related variants and since iron overload is a treatable condition, these results merit replication.

Testosterone and gonadotropin levels in men with dementia.

OBJECTIVES: Sex steroids such as testosterone and estradiol might protect the brain against Alzheimer's disease (AD). We previously found lower levels of testosterone in men with AD compared with controls. We wanted to assess levels of pituitary gonadotropins that regulate sex steroid levels, to determine whether primary or secondary hypogonadism was responsible for low levels of testosterone in cases. METHOD: We included 45 men with AD (McKhann, 1987), 15 men with other types of dementia and 133 elderly controls from the Oxford Project to Investigate Memory and Ageing. Gonadotropins (follicle stimulating hormone or FSH and luteinizing hormone or LH), sex hormone binding globulin (SHBG, which determines the amount of free testosterone) and testosterone were measured using enzyme immunoassays. RESULTS: We found no difference in average LH (8.7 +/- 9 UI/L), FSH (13 +/- 17 UI/L) or SHBG (44 +/- 18 nmol/L) levels between AD cases and controls. Similar to our earlier findings, testosterone levels were significantly lower in men with AD (13 +/- 6 nmol/L) compared with controls (17 +/- 8, O.R. = 0.92, 95% C.I. = 0.87 to 0.97, p<0.005). Results were unchanged when controlled for age, SHBG and gonadotropin levels. CONCLUSION: Although normal, the levels of gonadotropins were inappropriately low for the levels of testosterone. Our results support a preliminary conclusion that secondary hypogonadism occurs in men with AD. This could be a consequence of brain degeneration. This is contrary to an earlier study (Bowen, 1999) that found raised levels of gonadotropins in cases with AD, suggesting primary hypogonadism. Our cohort was younger than theirs and gonadotropin levels increase with age. We are enlarging our data set to investigate whether primary hypogonadism occurs in older cases with AD or whether secondary hypogonadism precedes cognitive dysfunction in men at risk for AD. If this is true, testosterone replacement therapy for hypogonadal men at risk for dementia may be indicated.

Sensitivity and specificity of neuropsychological tests for mild cognitive impairment, vascular cognitive impairment and Alzheimer's disease.

BACKGROUND: Early diagnosis of dementia is important for those who might benefit from treatment. We designed a brief comprehensive neuropsychological test battery to help differentiate control subjects from patients with mild cognitive impairment (MCI) and dementia. METHOD: The battery included tests of memory, attention, executive function, speed, perception and visuospatial skills. It was administered to subjects from the OPTIMA cohort: 51 controls, 29 with MCI, 60 with 'possible' or 'probable' Alzheimer's disease (AD) (NINCDS/ADRDA) and 12 with cerebrovascular disease (CVD). Mann-Whitney U tests were used to compare performance of controls with other diagnostic groups. The sensitivity and specificity of the tests were determined using Receiver Operating Characteristic curve analyses. The effects of age, gender and years of education on test performance were determined with Spearman's rank correlations. RESULTS: The AD group performed worse than controls on all tests except an attention task. The Hopkins Verbal Learning Test and The Placing Test for episodic memory showed significant discriminative capacity between controls and other groups. Attention and processing speed tests discriminated CVD from controls. Category fluency, episodic memory tests and the CLOX test for executive function distinguished MCI from AD. Spearman's correlations showed negative associations between age and processing speed. Years of education affected performance on all tests, except The Placing Test. CONCLUSIONS: Certain neuropsychological tests have been shown to be sensitive and specific in the differential diagnosis of various types of dementia and may prove to be useful for detection of MCI.

The validity and reliability of 6 sets of clinical criteria to classify Alzheimer's disease and vascular dementia in cases confirmed post-mortem: added value of a decision tree approach.

Data from 204 participants from the Oxford Project to Investigate Memory and Ageing, who were diagnosed post-mortem using the histopathological criteria of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), were used to assess the validity of the clinical criteria for Alzheimer's disease (AD) of the 'National Institute of Neurological and Communicative Disorders and Stroke/the Alzheimer's Disease and Related Disorders Association' (NINCDS/ADRDA). Cases who had been diagnosed as NINCDS/ADRDA 'probable AD' in life were usually confirmed at autopsy, but half of the NINCDS/ADRDA 'negative' cases were not (low specificity). It was hypothesized that the overall clinical impression may have taken precedence over the use of the actual criteria. We therefore investigated the validity and reliability of the clinical criteria using a computerized 'dementia diagnosis system' for each of 6 sets of criteria [Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), NINCDS/ADRDA and three sets of criteria specifically for vascular dementia (VaD): NINCDS-AIREN, State of California Alzheimer's Disease Diagnostic and Treatment Centers (ADDTC), and Vascular Cognitive Impairment (VCI)] to classify a subset (n = 96) of the cases confirmed post-mortem. The use of the computerized system significantly (p = 0.01) increased the specificity (81%, similar to sensitivity) of the NINCDS/ADRDA diagnoses, which were shown to have 'moderate' inter-rater reliability. The DSM-IV criteria had good validity for AD when compared with post-mortem confirmation and showed 'substantial' inter-rater reliability. The ADDTC and VCI criteria for VaD had good specificity (88%) and sensitivity (75%), but only for one rater. The DSM-IV and NINCDS-AIREN criteria for VaD showed poor validity and inter-rater reliability. We conclude that the forced use of decision trees through a computerized system enhances the accuracy of the clinical diagnoses of dementia.

Association of the androgen receptor CAG repeat polymorphism with Alzheimer's disease in men.

We examined the CAG repeat polymorphism in exon 1 of the androgen receptor (AR) in an Oxford cohort of 150 cases (101 men) of definite or probable Alzheimer's disease (AD) and 190 elderly controls (140 men). We found that short alleles (< or = 20 CAG repeats) were associated with AD (adjusted odds ratio = 2.5, 95% confidence intervals: 1.2-5.0) in men, but not in women. This association appeared stronger in early-onset AD (< 65 years). We conclude that this AR polymorphism is of potential relevance to the risk of AD in men.

Peripheral infection evokes exaggerated sickness behaviour in pre-clinical murine prion disease.

Peripheral infections in mammals are characterised by local, systemic and CNS effects. The latter give rise to sickness behaviour. Pro-inflammatory cytokines such as interleukin-1beta (IL-1beta) are thought to be important mediators of this neuro-immune signalling (Cartmell et al., 1999). There is anecdotal evidence suggesting that peripheral infections in patients with Alzheimer's disease have more severe behavioural consequences than those in otherwise healthy elderly subjects, and it is well known that brain microglia are activated in the elderly and in Alzheimer's disease (McGeer et al., 1987). Using ME7-induced murine prion disease as a model of chronic neurodegeneration that displays chronic microglial activation, and the intra-peritoneal injection of bacterial lipopolysaccharide to mimic a peripheral infection, we have shown that the temperature and activity responses of animals with pre-clinical prion disease were exaggerated compared with controls, and that this was associated with a significant increase in brain levels of IL-1beta. We hypothesise that prior priming of microglia by the degenerative process, followed by further activation through signalling from the periphery, resulted in increased brain IL-1beta synthesis and the consequent acute sickness behavioural responses. These findings demonstrate an interaction between peripheral infection and pre-existing CNS inflammation and suggest that further stimulation of an already primed microglial population by a peripheral infection may drive disease progression in chronic inflammatory conditions such as Alzheimer's disease and prion disease.

Serum total testosterone is lower in men with Alzheimer's disease.

OBJECTIVES: The purpose of this study was to determine whether the level of serum total testosterone (TT) was different in cases of Dementia of the Alzheimer's Type (DAT) than in controls. SETTING AND DESIGN: We included 83 referred DAT cases and 103 cognitively screened volunteers (aged 75+/-9 years) from the Oxford Project To Investigate Memory and Ageing. METHODS: Information was obtained about potential confounds in the relation of DAT with testosterone, including age, gender, education, body mass index, smoking, (ab)use of alcohol, diabetes mellitus, endocrine therapy, and having undergone hysterectomy. TT was measured in non-fasting serum obtained between 10 and 12 a.m. using a competitive enzyme immunoassay. RESULTS: Men with DAT (n=39) had lower levels (p =0.005) of total serum testosterone (TT=14+/-5 nmol/L) than controls (n=41, TT=18+/-6 nmol/L). Lower TT was more likely in men with DAT, independent of potential confounds (Odds Ratio=0.78, 95% C.I.=0.68 to 0.91). In women there was no difference in TT levels between cases (n=44) and controls (n=62). MAIN FINDINGS: Our results suggested that low TT may be a co-morbid feature of DAT in men. However, low TT levels could also exacerbate the disease. CONCLUSIONS: Prospective longitudinal studies should investigate whether low TT levels precede or follow the onset of DAT (209 words).

Diagnosing dementia: interrater reliability assessment and accuracy of the NINCDS/ADRDA criteria versus CERAD histopathological criteria for Alzheimer's disease.

We investigated the interrater reliability and accuracy of two independent medical doctors in using NINCDS/ADRDA criteria to classify 82 elderly subjects enrolled in OPTIMA, a longitudinal study investigating dementia. Kappa statistics revealed moderate agreement (0.5) in overall classification of dementia type, and almost perfect agreement (0.9) on the absence or presence of dementia. Combining NINCDS/ADRDA 'possible' and 'probable' Alzheimer's disease (AD) categories produced substantial agreement (0.7). Comparison with CERAD histopathological criteria for AD showed that combining 'possible' and 'probable' AD resulted in a high sensitivity and accuracy, but a low specificity. To increase specificity, the NINCDS/ADRDA 'probable AD' category should be used alone. An important finding was that the accuracy of diagnoses of AD made from the case notes alone was not different from the diagnoses obtained following active involvement with participants.