Assessment of quantitative [18F]Sodium fluoride PET measures of knee subchondral bone perfusion and mineralization in osteoarthritic and healthy subjects

OBJECTIVE

Molecular information derived from dynamic [¹⁸F]sodium fluoride ([¹⁸F]NaF) PET imaging holds promise as a quantitative marker of bone metabolism. The objective of this work was to evaluate physiological mechanisms of [¹⁸F]NaF uptake in subchondral bone of individuals with and without knee osteoarthritis (OA).

METHODS

Eleven healthy volunteers and twenty OA subjects were included. Both knees of all subjects were scanned simultaneously using a 3T hybrid PET/MRI system. MRI MOAKS assessment was performed to score the presence and size of osteophytes, bone marrow lesions, and cartilage lesions. Subchondral bone kinetic parameters of bone perfusion (K₁), tracer extraction fraction, and total tracer uptake into bone (K_i) were evaluated using the Hawkins 3-compartment model. Measures were compared between structurally normal-appearing bone regions and those with structural findings.

RESULTS

Mean and maximum SUV and kinetic parameters K_i, K₁, and extraction fraction were significantly different between Healthy subjects and subjects with OA. Between-group differences in metabolic parameters were observed both in regions where the OA group had degenerative changes as well as in regions that appeared structurally normal.

CONCLUSIONS

Results suggest that bone metabolism is altered in OA subjects, including bone regions with and without structural findings, compared to healthy subjects. Kinetic parameters of [¹⁸F]NaF uptake in subchondral bone show potential to quantitatively evaluate the role of bone physiology in OA initiation and progression. Objective measures of bone metabolism from [¹⁸F]NaF PET imaging can complement assessments of structural abnormalities observed on MRI.

Association of cortical microinfarcts and cerebral small vessel pathology in the ageing brain

AIMS

Cortical microinfarcts (CMI) are frequently observed in the ageing brain independent of cognitive decline, but their aetiology is not fully elucidated. To examine the potential role of different vessel pathologies, including cerebral amyloid angiopathy (CAA), arteriolosclerosis-hyalinosis and thromboembolism in the development of CMI, we examined 80 autopsy cases with more than one CMI on routine neuropathological examination.

METHODS

Pial and intracortical vessels around CMI were assessed for their integrity with haematoxylin-eosin staining and antibodies against amyloid-β protein and fibrinogen using a semiquantitative four-level rating scale (absent to severe) in the hippocampus, and the frontal, temporal and occipital cortex. Four histological categories of changes were defined: CAA, vessel pathology other than CAA, thromboembolism and absence of vessel pathology near CMI.

RESULTS

A differential distribution of microvascular pathology was observed depending on brain regions. In the occipital cortex, CAA was commonly associated with CMI. In contrast, in the hippocampus and the frontal cortex, cases without any vascular pathology in pial and intracortical vessels were significantly more frequent.

CONCLUSIONS

The aetiology of CMI differs depending on brain location. CAA may play a role principally in the occipital cortex. The large number of intact vessels around the CMI (mainly in the frontal cortex and hippocampus) raises the possibility that pathologies other than structural microangiopathy, including hypoperfusion/arterial hypotension or large vessel atherosclerosis, play a role in the development of microvascular lesions. These results are relevant in the context of aetiopathogenesis of vascular changes associated with conditions like vascular dementia.

Clinical presentation and management of patients with primary hyperparathyroidism of the Swiss Primary Hyperparathyroidism Cohort: a focus on neuro-behavioral and cognitive symptoms

PURPOSE

To describe the clinical and biochemical profile of patients with primary hyperparathyroidism (PHPT) of the Swiss Hyperparathyroidism Cohort, with a focus on neurobehavioral and cognitive symptoms and on their changes in response to parathyroidectomy.

METHODS

From June 2007 to September 2012, 332 patients were enrolled in the Swiss PHPT Cohort Study, a nationwide prospective and non-interventional project collecting clinical, biochemical, and outcome data in newly diagnosed patients. Neuro-behavioral and cognitive status were evaluated annually using the Mini-Mental State Examination, the Hospital Anxiety and Depression Scale, and the Clock Drawing tests. Follow-up data were recorded every 6 months. Patients with parathyroidectomy had one follow-up visit 3-6 months' postoperatively.

RESULTS

Symptomatic PHPT was present in 43 % of patients. Among asymptomatic patients, 69 % (131/189) had at least one of the US National Institutes for Health criteria for surgery, leaving thus a small number of patients with cognitive dysfunction or neuropsychological symptoms, but without any other indication for surgery. At baseline, a large proportion showed elevated depression and anxiety scores and cognitive dysfunction, but with no association between biochemical manifestations of the disease and test scores. In the 153 (46 %) patients who underwent parathyroidectomy, we observed an improvement in the Mini-Mental State Examination (P = 0.01), anxiety (P = 0.05) and depression (P = 0.05) scores.

CONCLUSION

PHPT patients often present elevated depression and anxiety scores and cognitive dysfunction, but rarely as isolated manifestations. These alterations may be relieved upon treatment by parathyroidectomy.

Individual classification of mild cognitive impairment subtypes by support vector machine analysis of white matter DTI

BACKGROUND AND PURPOSE

MCI was recently subdivided into sd-aMCI, sd-fMCI, and md-aMCI. The current investigation aimed to discriminate between MCI subtypes by using DTI.

MATERIALS AND METHODS

Sixty-six prospective participants were included: 18 with sd-aMCI, 13 with sd-fMCI, and 35 with md-aMCI. Statistics included group comparisons using TBSS and individual classification using SVMs.

RESULTS

The group-level analysis revealed a decrease in FA in md-aMCI versus sd-aMCI in an extensive bilateral, right-dominant network, and a more pronounced reduction of FA in md-aMCI compared with sd-fMCI in right inferior fronto-occipital fasciculus and inferior longitudinal fasciculus. The comparison between sd-fMCI and sd-aMCI, as well as the analysis of the other diffusion parameters, yielded no significant group differences. The individual-level SVM analysis provided discrimination between the MCI subtypes with accuracies around 97%. The major limitation is the relatively small number of cases of MCI.

CONCLUSIONS

Our data show that, at the group level, the md-aMCI subgroup has the most pronounced damage in white matter integrity. Individually, SVM analysis of white matter FA provided highly accurate classification of MCI subtypes.

Telomere length, comorbidity, functional, nutritional and cognitive status as predictors of 5 years post hospital discharge survival in the oldest old

BACKGROUND

Telomere length has been considered in many cross-sectional studies as a biomarker of aging. However the association between shorter telomeres with lower survival at advanced ages remains a controversial issue. This association could reflect the impact of other health conditions than a direct biological effect.

OBJECTIVE

To test whether leukocyte telomere length is associated with 5-year survival beyond the impact of other risk factors of mortality like comorbidity, functional, nutritional and cognitive status.

DESIGN

Prospective study.

SETTING AND PARTICIPANTS

A population representative sample of 444 patients (mean age 85 years; 74% female) discharged from the acute geriatric hospital of Geneva University Hospitals (January-December 2004), since then 263 (59.2%) had died (December 2009).

MEASUREMENTS

Telomere length in leukocytes by flow cytometry.

RESULTS

In univariate model, telomere length at baseline and cognitive status were not significantly associated with mortality even when adjusting for age (R²=9.5%) and gender (R²=1.9%). The best prognostic predictor was the geriatric index of comorbidity (GIC) (R²=8.8%; HR=3.85) followed by more dependence in instrumental (R²=5.9%; HR=3.85) and based (R²=2.3%; HR=0.84) activities of daily living and lower albumin levels (R²=1.5%; HR=0.97). Obesity (BMI>30: R²=1.6%; HR=0.55) was significantly associated with a two-fold decrease in the risk of mortality compared to BMI between 20-25. When all independent variables were entered in a full multiple Cox regression model (R²=21.4%), the GIC was the strongest risk predictor followed by the nutritional and functional variables.

CONCLUSION

Neither telomeres length nor the presence of dementia are predictors of survival whereas the weight of multiple comorbidity conditions, nutritional and functional impairment are significantly associated with 5-year mortality in the oldest old.

Longitudinal analysis of cognitive performances and structural brain changes in late-life bipolar disorder

OBJECTIVES

Cross-sectional studies in bipolar disorder (BD) suggested the presence of cognitive deficits and subtle magnetic resonance imaging (MRI) changes in limbic areas that may persist at euthymic stages. Whether or not cognitive and MRI changes represent stable attributes of BD or evolve with time is still matter of debate. To address this issue, we performed a 2-year longitudinal study including detailed neuropsychological and magnetic resonance imaging (MRI) analyses of 15 euthymic older BD patients and 15 controls.

METHODS

Neuropsychological evaluation concerned working memory, episodic memory, processing speed, and executive functions. MRI analyses included voxel-based morphometry (VBM) analysis of gray matter including region of interest (ROI) analysis and tract-based spatial statistics (TBSS) analysis of white matter of diffusion tensor imaging derived fractional anisotropy (FA).

RESULTS

BD patients displayed significantly lower performances in processing speed and episodic memory but not in working memory and executive functions compared to controls. However, BD patients did not differ from controls in the mean trajectory of cognitive changes during the 2 years follow-up. In the same line, longitudinal gray matter (VBM, ROI) and white matter (TBSS FA) changes did not differ between BD patients and controls.

CONCLUSION

The lack of distinction between BD patients and controls in respect to the 2-year changes in cognition and MRI findings supports the notion that this disorder does not have a significant adverse impact on cognitive and brain aging. From this point of view, the present results convey a message of hope for patients suffering from BD.

Longitudinal analysis of cognitive performances and structural brain changes in late-life bipolar disorder

OBJECTIVES

Cross-sectional studies in bipolar disorder (BD) suggested the presence of cognitive deficits and subtle magnetic resonance imaging (MRI) changes in limbic areas that may persist at euthymic stages. Whether or not cognitive and MRI changes represent stable attributes of BD or evolve with time is still matter of debate. To address this issue, we performed a 2-year longitudinal study including detailed neuropsychological and magnetic resonance imaging (MRI) analyses of 15 euthymic older BD patients and 15 controls.

METHODS

Neuropsychological evaluation concerned working memory, episodic memory, processing speed, and executive functions. MRI analyses included voxel-based morphometry (VBM) analysis of gray matter including region of interest (ROI) analysis and tract-based spatial statistics (TBSS) analysis of white matter of diffusion tensor imaging derived fractional anisotropy (FA).

RESULTS

BD patients displayed significantly lower performances in processing speed and episodic memory but not in working memory and executive functions compared to controls. However, BD patients did not differ from controls in the mean trajectory of cognitive changes during the 2 years follow-up. In the same line, longitudinal gray matter (VBM, ROI) and white matter (TBSS FA) changes did not differ between BD patients and controls.

CONCLUSION

The lack of distinction between BD patients and controls in respect to the 2-year changes in cognition and MRI findings supports the notion that this disorder does not have a significant adverse impact on cognitive and brain aging. From this point of view, the present results convey a message of hope for patients suffering from BD.

Diabetes, comorbidities and increased long-term mortality in older patients admitted for geriatric inpatient care

AIMS

To study the specific impact of diabetes on long-term mortality in very old subjects with multiple comorbidities and functional disabilities.

METHODS

The prevalence of vascular disorders, global comorbidity load (cumulative illness rating scale [CIRS]) and functional disabilities (activities of daily living [ADL] and Lawton's instrumental ADL [IADL] scores) were determined according to diabetes status in a cohort of 444 patients (mean age 85.3±6.7 years; 74.0% women) admitted to our geriatric service. Also, the specific impact of diabetes on 4-year mortality was analyzed using Cox proportional-hazards models.

RESULTS

Diabetic patients had higher BMI scores (27.1±4.9 vs. 23.4±4.7 kg/m(2) in controls; P<0.001), and higher prevalences of hypertension (81.9% vs. 65.1%, respectively; P=0.003) and ischaemic heart disease (33.7% vs. 22.2%, respectively; P=0.033), but not of stroke and renal insufficiency. They also had more comorbidities (CIRS score excluding diabetes: 15.1±4.5 vs. 13.8±4.8, respectively; P=0.016) and functional disabilities. Diabetes was associated with mortality (HR: 1.42, 95% CI: 1.02-1.99; P=0.041) after adjusting for age, gender and BMI, and this persisted after adjusting for individual vascular comorbidities, but disappeared after adjusting for CIRS, ADL or IADL scores.

CONCLUSION

Diabetes was associated with 4-year mortality after adjusting for the inverse relationship between mortality and BMI. This association was better accounted for by the global comorbidity load and functional disabilities than by the individual vascular comorbidities. These findings suggest that the active management of all--rather than selected--comorbidities is the key to improving the prognosis for older diabetic patients.

[Vascular dementia: big effects of small lesions]

Vascular dementia due to multiple large strokes (multi-infarct dementia) is a well known entity. However, new clinicopathologic and neuroimaging data have highlighted the common occurrence of small vessel and microscopic vascular pathology in aging brains and recognized that vascular dementia due to small lesions is probably the most common form. In such cases, cortical microinfarcts are the strongest correlate of global cognitive function followed by basal ganglia and thalamic lacunes. Demyelination is only weekly associated with cognition and this relation is no longer significant after adjustement for the presence of lacunes. Awareness of the importance of small vascular lesions in brain aging, can improve diagnostic accuracy and help identify new targets, that could lead to novel therapeutic approaches in old age dementia.

IAGG workshop: health promotion program on prevention of late onset dementia

IAGG, WHO, and SFGG organized a international workshop on Health promotion programs on prevention of late on-set dementia. Thirty world specialists coming from Europe, North America, Asia, South America, Africa and Australia, shared their experience on methods and results of large epidemiological interventions to reduce incidents of dementia or delay its on-set. Chaired by Laura FRATIGLIONI, an expert in Epidemiological studies on dementia issues, the workshop gave opportunity for discussions and controversies about the state-of-the-art. Based on different national and international trials (ADAPT, MAPT, FINGER, GUDIAGE, GEM etc) the questions remained opened for different aspects of methodology, the choice of domain or multi domain intervention, the choice and the definition of the target populations, the best age of candidates, the issues related to the discrepancy between late effects, and interventions' duration. We are please to publish in the Journal, the presentations presented to this workshop. These publications will complete previously task force published in the journal in the last two years on methodological issues for Alzheimer's trials including end point, biomarkers, and the experience of past therapeutic trials.

Neuropathological analysis of lacunes and microvascular lesions in late-onset depression

AIMS

Previous neuropathological studies documented that small vascular and microvascular pathology is associated with cognitive decline. More recently, we showed that thalamic and basal ganglia lacunes are associated with post-stroke depression and may affect emotional regulation. The present study examines whether this is also the case for late-onset depression.

METHODS

We performed a detailed analysis of small macrovascular and microvascular pathology in the post mortem brains of 38 patients with late-onset major depression (LOD) and 29 healthy elderly controls. A clinical diagnosis of LOD was established while the subjects were alive using the DSM-IV criteria. Additionally, we retrospectively reviewed all charts for the presence of clinical criteria of vascular depression. Neuropathological evaluation included bilateral semi-quantitative assessment of lacunes, deep white matter and periventricular demyelination, cortical microinfarcts and both focal and diffuse gliosis. The association between vascular burden and LOD was investigated using Fisher's exact test and univariate and multivariate logistic regression models.

RESULTS

Neither the existence of lacunes nor the presence of microvascular ischaemic lesions was related to occurrence of LOD. Similarly, there was no relationship between vascular lesion scores and LOD. This was also the case within the subgroup of LOD patients fulfilling the clinical criteria for vascular depression.

CONCLUSIONS

Our results challenge the vascular depression hypothesis by showing that neither deep white matter nor periventricular demyelination is associated with LOD. In conjunction with our previous observations in stroke patients, they also imply that the impact of lacunes on mood may be significant solely in the presence of acute brain compromise.

[Review in geriatric medicine]

In 2010, a study emphasizes the difficulty to predict disability trajectories in the last year of life. A meta analysis shows the effectiveness of post-acute geriatric rehabilitation in reducing functional decline after hospitalisation. Several studies evaluated pneumococcal and herpes zoster vaccines' efficacy. A short and simple intervention is effective in reducing benzodiazepine use. The effect of vitamine D on falls and fractures has been further evaluated in several studies. Diagnostic criteria for dementias, including Alzheimer's disease, are moving to better acknowledge their preclinical stages.

The primary care physician and Alzheimer's disease: an international position paper

This paper aims to define the role of the primary care physician (PCP) in the management of Alzheimer's disease (AD) and to propose a model for a work plan. The proposals in this position paper stem from a collaborative work of experts involved in the care of AD patients. It combines evidence from a literature review and expert's opinions who met in Paris, France, on July 2009 during the International Association of Geriatrics and Gerontology (IAGG) World Congress. The PCP's intervention appears essential at many levels: detection of the onset of dementia, diagnostic management, treatment and follow-up. The key role of the PCP in the management of AD, as care providers and care planners, is consolidated by the family caregiver's confidence in their skills. In primary care practice the first step is to identify dementia. The group proposes a "case finding" strategy, in target situations in which dementia should be detected to allow, secondarily, a diagnosis of AD, in certain cases. We propose that the PCP identifies 'typical' cases. In typical cases, among older subjects, the diagnosis of "probable AD" can be done by the PCP and then confirm by the specialist. While under-diagnosis of AD exists, so does under-disclosure. Disclosure to patient and family should be done by both specialist and PCP. Then, the PCP has a central role in management of the disease with the general objectives to detect, prevent and treat, when possible, the complications of the disease (falls, malnutrition, behavioural and psychological symptoms of dementia). The PCP needs to give basic information to the caregiver on respite care and home support services in order to prevent crisis situations such as unplanned institutionalisation and "emergency" hospital admission. Finally, therapeutic research must be integrated in the daily practice of PCP. It is a matter of patients' right to benefit from access to innovation and clinical research whatever his age or diseases, while of course fully respecting the rules and protective measures that are in force.

[Caring for the caregiver]

Dementing disorders usually evolve over several years and alter cognitive performances, behavior and social abilities. Progressively, the patients lose their independence. Families will play a key role for the demented patient and have to adapt to the evolution of his or her needs. They will have to watch over, guide and help the demented proxy. The families' invaluable contribution and the numerous difficulties they encounter while they care for their demented proxy are insufficiently recognized. The deleterious consequences on the carers are currently better known than the determinants of these consequences. Families often need information, counselling and psychological support. Psycho-educational programs represent one of the possible strategies to help families and carers of patients with dementia.

Working memory load-related electroencephalographic parameters can differentiate progressive from stable mild cognitive impairment

Recent studies described several changes of endogenous event-related potentials (ERP) and brain rhythm synchronization during memory activation in patients with Alzheimer's disease (AD). To examine whether memory-related EEG parameters may predict cognitive decline in mild cognitive impairment (MCI), we assessed P200 and N200 latencies as well as beta event-related synchronization (ERS) in 16 elderly controls (EC), 29 MCI cases and 10 patients with AD during the successful performance of a pure attentional detection task as compared with a highly working memory demanding two-back task. At 1 year follow-up, 16 MCI patients showed progressive cognitive decline (PMCI) and 13 remained stable (SMCI). Both P200 and N200 latencies in the two-back task were longer in PMCI and AD cases compared with EC and SMCI cases. During the interval 1000 ms to 1700 ms after stimulus, beta ERS at parietal electrodes was of lower amplitude in PMCI and AD compared with EC and SMCI cases. Univariate models showed that P200, N200 and log% beta values were significantly related to the SMCI/PMCI distinction with areas under the receiver operating characteristic curve of 0.93, 0.78 and 0.72, respectively. The combination of all three EEG hallmarks was the stronger predictor of MCI deterioration with 90% of correctly classified MCI cases. Our data reveal that PMCI and clinically overt AD share the same pattern of working memory-related EEG activation characterized by increased P200-N200 latencies and decreased beta ERS. They also show that P200 latency during the two-back task may be a simple and promising EEG marker of rapid cognitive decline in MCI.

Endocrine disruption mechanism of o,p′-DDT in mature male tilapia (Oreochromis niloticus)

The aim of the present study was to evaluate, in vivo, the potential of o,p'-DDT to disrupt the endocrine system of mature male tilapia. In particular, the possibility that o,p'-DDT effects were mediated directly via the estrogen receptor (ER). Compounds with known ability to bind to the ER were employed: estradiol to induce and tamoxifen to inhibit the estrogenic effects result of the activation of the ER. In addition, an aromatase inhibitor, 4-hydrxyandrostenedione (4-OHA), was used to assess the ability of o,p'-DDT to induce estrogenic effects in a surrounding of low estradiol concentration. The effects of estradiol and o,p'-DDT were studied alone or in the presence of tamoxifen or 4-OHA at the end of a 12-day period of exposure. The main endpoints measured were plasma alkaline-labile phosphorous (ALP; an indirect indicator of vitellogenin), estradiol, testosterone and o,p'-DDT. It was found that o,p'-DDT was able to induce the vitellogenesis (measured as plasma ALP increase) and decrease the circulating levels of estradiol and testosterone. Interestingly, o,p'-DDT kept this ability in whole fish with low concentrations of estradiol which would exclude endogenous estradiol as indirect mediator of the estrogenic effects induced by o,p'-DDT. In addition, the plasma concentration of o,p'-DDT, instead of that of estradiol, was closely related to the plasma ALP increase induced by o,p'-DDT. This indicates that o,p'-DDT could have directly activated the vitellogenesis. The antiestrogenic action of tamoxifen to inhibit the vitellogenesis and the decrease on plasma estradiol induced by o,p'-DDT indicates that o,p'-DDT can bind directly to the ER. In conclusion, this in vivo study shows that o,p'-DDT has the potential to disrupt the endocrine system and strongly supports that the estrogenic actions of o,p'-DDT involve binding to the ER.

Stereological analysis of neuropil threads in the hippocampal formation: relationships with Alzheimer's disease neuronal pathology and cognition

Although neuropil threads are thought to account for 85-90% of cortical tau pathology in brain ageing, their clinical significance remains controversial. Previous studies have measured densities, rather than absolute numbers, and most did not take into account possible interactions among the pathological hallmarks of Alzheimer's disease (AD). We report here stereological estimates of total neurofibrillary tangle (NFT) and neuron numbers as well as total amyloid volume and neuropil thread (NT) length, in the hippocampus and entorhinal cortex of 19 very old individuals (age range: 83-101 years) with various degrees of cognitive decline. Total NT length in all areas studied increased in mildly demented cases but showed a marked decrease in Clinical Dementia Rating (CDR) scale 3 cases. Both total NFT and neuron numbers were related to NT length in the CA1 field and entorhinal cortex. A strong positive relationship was also present between the total NFT numbers in the entorhinal cortex and NT length in the CA1 field and dentate gyrus. Total NT length in the CA1 field was related to both CDR scores and presence or absence of dementia explaining 7% and 37% of their variability respectively. In multivariate models, this relationship was highly dependent on the severity of NFT formation in this area. Our data reveal that NT formation in hippocampal subdivisions and entorhinal cortex accompanies AD neuronal pathology in early stages of the degenerative process, yet its rate may decrease in severe dementia. In terms of clinicopathological correlations, NT length in the hippocampal formation does not represent an independent marker of dementia severity.

Cortical microinfarcts and demyelination affect cognition in cases at high risk for dementia

OBJECTIVE

To investigate the possible synergistic effect of microvascular lesions with mild Alzheimer disease (AD) pathology in mixed cases.

METHODS

We assessed the cognitive impact of cortical microinfarcts, deep white matter and periventricular demyelination, as well as diffuse and focal gliosis in a large series of 43 prospectively evaluated autopsy cases scored Braak neurofibrillary tangle stage III, but without macroscopic vascular pathology or substantial non-AD, nonvascular microscopic lesions. We included bilateral assessment of all types of microvascular lesions and used multivariate models that control for the possible confounding effect of age and amyloid beta-protein (Abeta) deposits.

RESULTS

Only cortical microinfarcts and periventricular demyelination were significantly associated with the Clinical Dementia Rating Scale (CDR) score. In a univariate model, the cortical microinfarct score explained 9% of the variability in CDR scores and periventricular demyelination score 7.3%. Abeta deposition explained only 3.5% of the CDR variability. In a logistic regression model, both variables were strongly associated with the presence of dementia (R = 0.45; p < 0.05). When the CDR sum of the boxes was used, Abeta staging explained 8.9% of cognitive variability, the addition of cortical microinfarct predicted an extra 15.5%, and that of periventricular demyelination an extra 9%.

CONCLUSIONS

Cortical microinfarcts and, to a lesser degree, periventricular demyelination contribute to the cognitive decline in individuals at high risk for dementia. Both should be taken into account when defining the neuropathologic criteria for mixed dementia.

[Geriatrics]

A new vaccine reduces the incidence and severity of zoster and its complications in older persons. A cost-effectiveness analysis highlights the implication of CDC's recent recommendation to vaccinate all persons aged 60 years and over. A meta-analysis confirms that the chronic use of sedatives in older persons provides modest benefits and important risks. Unfortunately, melatonin does not seem to be a useful alternative. A systematic review of interventions to prevent pressure ulcers provides scientific support to measures empirically used in most institutions. Finally, a randomized controlled trial questions the clinical benefit of atypical neuroleptics in Alzheimer's disease and a comprehensive review of pharmacological trials in mild cognitive impairment reports no benefit of any of the tested drugs on conversion rate to Alzheimer's disease.

MRI protocols for whole-organ assessment of the knee in osteoarthritis

One of the critical challenges in developing structure-modifying therapies for arthritis, especially osteoarthritis (OA), is measuring changes in progression of joint destruction. Magnetic resonance imaging (MRI) offers considerable promise in this regard. Not only can MRI quantify articular cartilage volume and morphology with high precision and accuracy, but it can also examine several other important articular components, and thus offer a unique opportunity to evaluate the knee and other joints as whole organs. On December 5 and 6, 2002, OMERACT (Outcome Measures in Rheumatology Clinical Trials) and OARSI (Osteoarthritis Research Society International), with support from various pharmaceutical companies listed at the beginning of this supplement, held a Workshop for Consensus on Osteoarthritis Imaging in Bethesda, MD. The aim of the Workshop was to provide a state-of-the-art review of imaging outcome measures for OA of the knee to help guide scientists and pharmaceutical companies who want to use MRI in multi-site studies of OA. Applications of MRI were initially reviewed by a multidisciplinary, international panel of expert scientists and physicians from academia, the pharmaceutical industry and regulatory agencies. The findings of the panel were then presented to a wider group of participants for open discussion. The following report summarizes the results of these discussions with respect to MRI acquisition techniques for whole-organ assessment of the knee in OA. The discussion reviews the selection and qualification of imaging sites for clinical trials, designing imaging protocols for whole-organ assessment of OA, and key considerations in image quality (IQ) control and data management.

MRI and non-cartilaginous structures in knee osteoarthritis

Magnetic resonance imaging (MRI) provides a sensitive tool for examining all the structures involved in the osteoarthritis (OA) process. While much of the MRI literature previously focussed on cartilage, there is increasing research on whole-organ evaluation and including features such as synovitis, bone marrow edema, and meniscal and ligamentous pathology. The aim of this session at the Outcome Measures in Rheumatology Clinical Trials (OMERACT)-Osteoarthritis Research Society International (OARSI) Workshop for Consensus in Osteoarthritis Imaging was to describe the current MRI methods for identifying and quantifying non-cartilaginous structures and review their associations with both OA symptoms and structural progression. Although there is much experience in measuring synovitis (derived from the rheumatoid arthritis literature), only one study has reported an association of MRI-detected synovitis and effusions with OA pain. Bone marrow edema lesions, which may represent areas of trabecular remodelling, have been associated with pain and compartment-specific structural deterioration. MRI studies have confirmed the frequency and importance of meniscal damage in progressive cartilage loss, but not related such damage to symptoms. Osteophytes have been associated with cartilage loss and malalignment to the side of the osteophyte. Ligament damage, including anterior cruciate ligament tears, has been found more commonly than expected in painful OA knees. Improvements in quantitative and semi-quantitative assessments of non-cartilage features will greatly assist understanding of the OA process and its response to therapy.

Frontal theta event-related synchronization: comparison of directed attention and working memory load effects

Early studies showed that long-term encoding and retrieval of new information is associated with modulation of the theta rhythm. More recently, changes in theta power amplitude over frontal electrode sites were reported during working memory, yet their relative significance in regard to attentional and memory processes remains unclear. Event-related synchronisation responses in the 4-7.5 Hz theta EEG frequency band was studied in 12 normal subjects performing four different tasks: two working memory tasks in which load varied from one (1-back task) to two (2-back task) items, an oddball detection (attention) task and a passive fixation task. A phasic theta increase was observed following stimulus apparition on all electrode sites within each task, with longer culmination peak and maximal amplitude over frontal electrodes. Frontal theta event-related synchronization (ERS) was of higher amplitude in the 1-back, 2-back and detection tasks as compared to the passive fixation task. Additionally, the detection task elicited a larger frontal and central theta ERS than the 2-back task. By analyzing theta ERS characteristics in various experimental conditions, the present study reveals that early phasic theta response over frontal regions primarily reflects the activation of neural networks involved in allocation of attention related to target stimuli rather than working memory processes.

[Is there a treatment for Alzheimer's disease?]

Alzheimer's disease is a frequent neurodegenerative disease, which affects more than one third of elderly persons over 80 years. No curative treatment is currently available for this disease, but symptomatic treatments have produced significant improvements in patients' condition. Cholinesterase inhibitors should be prescribed for early and moderate stages and memantine for more severe stages of the disease. These drugs have an impact on cognitive performances, may delay functional decline and improve behaviour disturbances. From a preventive perspective, evidence of benefit from early management of vascular risk factors is accumulating. In the near future, the improved comprehension of the underlying mechanisms of Alzheimer's disease will hopefully bring new treatments, thats will delay or modify its course.

[Diagnosis and treatment of vascular dementia]

Vascular dementia is the second cause of dementia after Alzheimer's disease. It is a broad term which includes dementia due to: single or multiple infarcts related to large vessel disease, subcortical ischemic pathology linked to small vessel disease, hemorrhages, and hypoperfusion. Furthermore, vascular and Alzheimer lesions often coexist leading to a mixed dementia. The diagnosis should be considered in the presence of dementia, clinical or neuroradiological signs of cerebrovascular disease and a plausible link between the two. Newly identified preventive strategies and encouraging results of recent trials using cholinesterase inhibitors or memantine suggest therapeutic potential.

Aging and working memory: early deficits in EEG activation of posterior cortical areas

Using the n-back task, we recently identified, in young subjects, a positive-negative event related potential component (PN(wm)) in a time-range window between 140 and 280 ms after stimulus onset representing an electrophysiological correlate of working memory load. To evaluate age-related electrophysiological changes in working memory processing, we applied the same neuropsychological paradigm and compared densities of the PN(wm) component in 17 young (mean age: 26) and 17 healthy elderly individuals (mean age: 75). Both age groups displayed a PN(wm) component during the two working memory tasks. For the 1-back task, densities were similar in both young and elderly individuals. In contrast, PN(wm) densities increased with higher memory load (2-back>1-back) in the younger but not in the older group. This difference was mainly observed over parietal electrodes suggesting an impaired activation of neural generators within this brain region. The present results are consistent with the hypothesis of decreased brain reserve in the elderly and provide evidence for age-related deficits in the recruitment of posterior cortical neurons with increasing working memory load.

ADC mapping of the aging frontal lobes in mild cognitive impairment

Normal aging, leukoaraiosis (LA) and vascular disease particularly involve the human frontal lobes. We decided to investigate a population of elderly patients referred for neuroimaging because of progressive minor cognitive deficits but no dementia. They underwent conventional Magnetic resonance imaging (MRI) using axial T1 and T2-weighted imaging as well as coronal FLAIR sequences in addition to the axial diffusion-weighted MRI. MRI allowed us to differentiate patients with leukoaraïosis (LA+) from those without it (LA-) and mapping of the apparent diffusion coefficient (ADC) to investigate local tissular water motion. We observed an increase in the ADC in all investigated patients with increasing age (r=0.326, p=0.002). This increase was observed in both patients groups (LA+ and LA-). In addition, the LA+ group had significant higher ADC values than the LA- group after controlling for age (p<0.0001).

Tangle and neuron numbers, but not amyloid load, predict cognitive status in Alzheimer's disease

OBJECTIVE

To examine the relationship between stereologic estimates of AD-related pathology and severity of cognitive deficits in brain aging.

BACKGROUND

Previous studies reported substantial contributions of neurofibrillary tangles (NFT), amyloid deposits, and neuronal loss to the development of dementia. However, the prediction of cognitive status based on nonstereologic quantification of these measures has led to conflicting results. Such studies have measured densities, rather than absolute numbers, and most do not take into account the potential interaction between the above pathologic hallmarks in a global multivariate analysis.

METHODS

Clinicopathologic study in 22 elderly cases. Cognitive status assessed prospectively using the Mini-Mental State Examination (MMSE); stereologic assessment of NFT, unaffected neurons, and total amyloid volume in the CA1 field of the hippocampus, entorhinal cortex, and area 9. Statistical analysis was performed using both univariate and multivariate linear regression models.

RESULTS

High total NFT counts but not amyloid volume were strongly associated with a lower number of unaffected neurons in all areas studied. A high proportion of variability in MMSE scores was explained by NFT and neuronal counts in the CA1 field (83% and 85.4%), entorhinal cortex (87.8% and 83.7%), and area 9 (87% and 79%); amyloid volume in the entorhinal cortex, but not in the CA1 field and area 9, accounted for 58.5% of MMSE variability. Multivariate analyses showed that total NFT counts in the entorhinal cortex and area 9 as well as neuron numbers in the CA1 field were the best predictors of MMSE score.

CONCLUSIONS

These new stereologic data indicate that neuronal pathology in hippocampal formation and frontal cortex closely reflects the progression of cognitive deficits in brain aging and AD. They also demonstrate that amyloid volume has no additional predictive value, in terms of clinicopathologic correlations, beyond its interaction with NFT.

Stereologic analysis of neurofibrillary tangle formation in prefrontal cortex area 9 in aging and Alzheimer's disease

Alzheimer's disease (AD) is characterized neuropathologically by several features including extensive neuronal death in the cerebral cortex. In fact, while neuropathological changes restricted to the hippocampal formation are a consistent reflection of age-related memory impairment, overt dementia is present only in cases with neocortical involvement. Several quantitative studies have reported a substantial loss of neurons from these regions and a parallel increase in the number of neurofibrillary tangles (NFT). However, accurate quantitative data on the dynamics of NFT formation are lacking. In the present study, we performed a stereologic analysis of the proportions of intracellular and extracellular (ghost) NFT, and unaffected neurons in the deep part of layer III (layer IIIc) and the superficial part of layer V (layer Va) of Brodmann's prefrontal cortex area 9. Elderly cognitively unimpaired cases were compared with cases with different degrees of cognitive dysfunction. The data revealed differential rates of formation of intracellular and extracellular NFT between the two layers, and confirmed the presence of a severe disease-associated, but not age-related, neuronal loss. It was also shown that a susbtantial number of pyramidal cells may persist either unaffected or in a transitional stage of NFT formation in both neocortical layers. These results suggest that a considerable number of neurons containing an intracellular NFT exists in the neocortex until late in the course of AD. Whereas it is not possible to assess whether such transitional neurons are fully functional, these affected neurons might respond positively to therapeutic strategies aimed at protecting the cells that are prone to neurofibrillary degeneration in AD.

Magnetic resonance imaging of articular cartilage

Magnetic resonance imaging is the optimal modality for assessing articular cartilage because of superior soft tissue contrast, direct visualization of articular cartilage, and multiplanar capability. Despite these advantages, there has been disagreement as to the efficacy of magnetic resonance imaging of articular cartilage. The reason for this controversy is multifactorial but in part is attributable to the lack of the use of optimized pulse sequences for articular cartilage. The current authors will review the current state of the art of magnetic resonance imaging of articular cartilage and cartilage repair procedures, discuss future new directions in imaging strategies and methods being developed to measure cartilage thickness and volume measurements, and propose a magnetic resonance imaging protocol to evaluate cartilage that is achievable on most magnetic resonance scanners, vendor independent, practical (time and cost efficient), and accepted and used by a majority of musculoskeletal radiologists.

Clinical validity of A beta-protein deposition staging in brain aging and Alzheimer disease

Braak's neurofibrillary tangle (NFT) pathology staging system of Alzheimer disease (AD) correlates generally with clinical data. Recently, Braak's group proposed an Abeta-protein staging based on the progression of amyloid deposition in the medial temporal lobe. To examine its clinical validity and evaluate whether it adds predictive power to NFT-based staging, we performed a study comparing both neuropathological classifications with clinical dementia rating scale (CDR) scores in a large autopsy series. The 2 neuropathological staging systems were strongly correlated. Their association with clinical severity was highly significant. However, the strength of the relationship was greater for NFT-based staging. It accounted for 26.5% of the variability in clinical severity, Abeta-protein-based staging for 13.0%, and age for 4.4%. Compared to NFT-based staging, the Abeta-protein-based system was less able to distinguish mild cognitive changes from dementia and showed marked overlap among the various stages of cognitive decline. In a multivariate model, NFT and age together accounted for 27.2% of the clinical variability and the addition of Abeta-protein deposition staging could only explain an extra 2.9%. Our data support the close relationship between NFT progression and amyloid formation within the medial temporal lobe proposed by Braak's group but demonstrate the limited value of Abeta-protein deposition staging in terms of clinicopathological correlations.