[18F]2-fluoro-2-deoxy-sorbitol ([18F]FDS) PET imaging repurposed for quantitative estimation of blood-brain barrier permeability in a rat model of Alzheimer's disease

Numerous studies suggest that blood-brain barrier (BBB) dysfunction may contribute to the progression of Alzheimer's disease (AD). Clinically available neuroimaging methods are needed for quantitative "scoring" of BBB permeability in AD patients. [18F]2-fluoro-2-deoxy-sorbitol ([18F]FDS), which can be easily obtained from simple chemical reduction of commercial [18F]2-fluoro-2-deoxy-glucose ([18F]FDG), was investigated as a small-molecule marker of BBB permeability, in a preclinical model of AD using in vivo PET imaging. Chemical reduction of [18F]FDG to [18F]FDS was obtained with a 100% conversion yield. Dynamic PET acquisitions were performed in the APP/PS1 rat model of AD (TgF344-AD, n=3) compared with age-matched littermates (WT, n=4). The brain uptake of [18F]FDS was determined in selected brain regions, delineated from a coregistered rat brain template. The brain uptake of [18F]FDS in the brain regions of AD rats versus WT rats was compared using a 2-way ANOVA. The uptake of [18F]FDS was significantly higher in the whole-brain of AD rats, as compared with WT rats (p<0.001), suggesting increased BBB permeability. Enhanced brain uptake of [18F]FDS in AD rats was significantly different across brain regions (p<0.001). Minimum difference was observed in the amygdala (+89.0±7.6%, p<0.001) and maximum difference was observed in the midbrain (+177.8±29.2%, p<0.001). [18F]FDS, initially proposed as radiopharmaceutical to estimate renal filtration using PET imaging, can be repurposed for non-invasive and quantitative determination of BBB permeability in vivo. Making the best with the quantitative properties of PET imaging, it was possible to estimate the extent of enhanced BBB permeability in a rat model of AD.

Neuropsychiatric and cognitive features of major depressive disorder in aging, based on the data from the US National Alzheimer's Coordinating Center (NACC)

OBJECTIVE

The diagnosis of Major Depressive Disorder (MDD) is based on the DSM-V criteria and is established by a clinician. This allows quantifying depression based on clinical criteria. As such, MDD differs from other types of depressions that are measured by subjective scales. Here, we evaluated the MDD risk factor on other neuropsychiatric symptoms (NPS) as well as MDD association with cognitive performance in Alzheimer's disease (AD), Mild Cognitive Impairment (MCI) and Healthy Controls (HC).

METHODS

Data of 208 patients with AD, 291 patients with MCI and 647 HC were extracted from the National Alzheimer's Coordinating Center database. All participants included in this study were assessed by a physician for the MDD criteria, underwent an NPS evaluation using the NeuroPsychiatric Inventory, and a comprehensive cognitive assessment. Participants were classified as being with and without MDD. We performed logistic regression and MANCOVA models respectively with NPS and cognitive performance as variables of interest and MDD as fixed factors within each group. The MANCOVA was controlled for the effects of age, sex, and education.

RESULTS

MDD increased the risk for psychotic, affective and behavioral NPS in MCI, as well as affective and behavioral NPS in HC and AD. Also, MCI with MDD had lower performance on selective attention and mental flexibility.

CONCLUSIONS

MDD seems to increase the probability of a prevalence of NPS in all groups (HC, MCI and AD). Longitudinal data processing would help to understand the neuropsychiatric evolution of elderly subjects with MDD.

[Menopause hormone therapy and cognition. Postmenopausal women management: CNGOF and GEMVi clinical practice guidelines]

The results of the WHI, which reported a doubling of the risk of Alzheimer's disease (AD) and a decline in cognitive function in women who were given menopause hormone therapy (MHT), have raised concerns on the deleterious impact of MHT on the central nervous system. Such as for the cardiovascular system, the very late age of initiation of treatment and the nature of the molecules have led to conclusions that cannot be extended to women in their fifties, at the onset of their menopause which is the usual age of MHT initiation. The molecules, which are used in France, 17-beta estradiol and natural progesterone (or its isomer, dydrogesterone) are very different from the equine conjugated estrogens and medroxyprogesterone acetate used in the WHI. It can now be stated that if MHT is started within the window of opportunity (i.e. before the age of 60 or within the first 10years after the beginning of menopause) no deleterious effect on cognition is observed. Moreover, cognition remains relatively stable at the beginning of menopause since the cognitive reserve as well as the different compensation circuits allow compensation for estrogen deficiency. This does not in any way prejudge a possible positive effect of MHT on AD, which is very difficult to demonstrate, as the age of onset of this dementia is very late, 20 or 30years after the initiation of treatment.

Highly integrated workflows for exploring cardiovascular conditions: Exemplars of precision medicine in Alzheimer's disease and aortic dissection

For precision medicine to be implemented through the lens of in silico technology, it is imperative that biophysical research workflows offer insight into treatments that are specific to a particular illness and to a particular subject. The boundaries of precision medicine can be extended using multiscale, biophysics-centred workflows that consider the fundamental underpinnings of the constituents of cells and tissues and their dynamic environments. Utilising numerical techniques that can capture the broad spectrum of biological flows within complex, deformable and permeable organs and tissues is of paramount importance when considering the core prerequisites of any state-of-the-art precision medicine pipeline. In this work, a succinct breakdown of two precision medicine pipelines developed within two Virtual Physiological Human (VPH) projects are given. The first workflow is targeted on the trajectory of Alzheimer's Disease, and caters for novel hypothesis testing through a multicompartmental poroelastic model which is integrated with a high throughput imaging workflow and subject-specific blood flow variability model. The second workflow gives rise to the patient specific exploration of Aortic Dissections via a multi-scale and compliant model, harnessing imaging, computational fluid-dynamics (CFD) and dynamic boundary conditions. Results relating to the first workflow include some core outputs of the multiporoelastic modelling framework, and the representation of peri-arterial swelling and peri-venous drainage solution fields. The latter solution fields were statistically analysed for a cohort of thirty-five subjects (stratified with respect to disease status, gender and activity level). The second workflow allowed for a better understanding of complex aortic dissection cases utilising both a rigid-wall model informed by minimal and clinically common datasets as well as a moving-wall model informed by rich datasets.

What do we know about technologies for dementia-related wandering? A scoping review: Examen de la portée : Que savons-nous à propos des technologies de gestion de l'errance liée à la démence?

BACKGROUND

Occupational therapists use technologies to manage wandering-related risks to promote safety and independence among individuals with dementia living in the community.

PURPOSE

The purpose of this review was to examine types of technologies used to manage wandering behaviour.

METHOD

Using a modification of Arksey and O'Malley's methodology, we systematically searched peer-reviewed and grey literature on technologies used in home or supportive care environments for persons with dementia at risk for wandering. Data from the studies were analyzed descriptively.

FINDINGS

The literature described 83 technologies. Nineteen devices were clinically tested. Interventions ranged from alarm products to mobile locator devices. Benefits included reductions in risk and caregiver burden.

IMPLICATIONS

Occupational therapy strategies include technologies to enhance function in persons with dementia. Technologies can also reduce risks of wandering and should be affordable. Ethical issues of the use of technology must be addressed. More research is needed to increase levels of evidence.

[Cataract surgery among 50 Alzheimer's patient (55 eyes)]

OBJECTIVE

Cataract surgery for 50 Alzheimer patients (55 eyes).

METHODS

Cinquante Alzheimer's patients with 0≤MMS≤25, with bilateral disabling cataracts were included for surgery. The surgical technique is analyzed.

RESULTS AND CONCLUSION

The preoperative examination of Alzheimer's patients is time consuming and requires experience in this area, which is important to integrate into the practice of ophthalmology. The type of cataract is unusual, with a predilection for pseudoexfoliation syndrome and zonular fragility that has to be managed during surgery. The procedure may be performed under local anesthesia. Three months after surgery, Alzheimer's patients demonstrated improved visual acuity (P<0.001) with no worsening of their dementia.

Physical activity limits the effects of age and Alzheimer's disease on postural control

The aim was to study the possible influence of physical activity on the postural performance of subjects with Alzheimer's disease (AD). The postural performance (i.e. surface area of the center of foot pressure displacement) of 3 groups was compared: Alzheimer active group (AA), Alzheimer non-active group (ANA) and healthy non-active group (HNA). The AA group's postural performance was superior to that of the ANA and HNA groups. AD disturbed postural performance but participation in regular physical activity made it possible to limit the disturbing effects of AD to a surprising extent, since the postural performance of active AD subjects was also superior to that of healthy subjects.

[Repetitive transcranial magnetic stimulation: A potential therapy for cognitive disorders?]

Considering the limited effectiveness of drugs treatments in cognitive disorders, the emergence of noninvasive techniques to modify brain function is very interesting. Among these techniques, repetitive transcranial magnetic stimulation (rTMS) can modulate cortical excitability and have potential therapeutic effects on cognition and behaviour. These effects are due to physiological modifications in the stimulated cortical tissue and their associated circuits, which depend on the parameters of stimulation. The objective of this article is to specify current knowledge and efficacy of rTMS in cognitive disorders. Previous studies found very encouraging results with significant improvement of higher brain functions. Nevertheless, these few studies have limits: a few patients were enrolled, the lack of control of the mechanisms of action by brain imaging, insufficiently formalized technique and variability of cognitive tests. It is therefore necessary to perform more studies, which identify statistical significant improvement and to specify underlying mechanisms of action and the parameters of use of the rTMS to offer rTMS as a routine therapy for cognitive dysfunction.

The toxicity of aluminium in humans

We are living in the 'aluminium age'. Human exposure to aluminium is inevitable and, perhaps, inestimable. Aluminium's free metal cation, Alaq(3+), is highly biologically reactive and biologically available aluminium is non-essential and essentially toxic. Biologically reactive aluminium is present throughout the human body and while, rarely, it can be acutely toxic, much less is understood about chronic aluminium intoxication. Herein the question is asked as to how to diagnose aluminium toxicity in an individual. While there are as yet, no unequivocal answers to this problem, there are procedures to follow to ascertain the nature of human exposure to aluminium. It is also important to recognise critical factors in exposure regimes and specifically that not all forms of aluminium are toxicologically equivalent and not all routes of exposure are equivalent in their delivery of aluminium to target sites. To ascertain if Alzheimer's disease is a symptom of chronic aluminium intoxication over decades or breast cancer is aggravated by the topical application of an aluminium salt or if autism could result from an immune cascade initiated by an aluminium adjuvant requires that each of these is considered independently and in the light of the most up to date scientific evidence. The aluminium age has taught us that there are no inevitabilities where chronic aluminium toxicity is concerned though there are clear possibilities and these require proving or discounting but not simply ignored.

Aluminum, the genetic apparatus of the human CNS and Alzheimer's disease (AD)

The genomes of eukaryotes orchestrate their expression to ensure an effective, homeostatic and functional gene signaling program, and this includes fundamentally altered patterns of transcription during aging, development, differentiation and disease. These actions constitute an extremely complex and intricate process as genetic operations such as transcription involve the very rapid translocation and polymerization of ribonucleotides using RNA polymerases, accessory transcription protein complexes and other interrelated chromatin proteins and genetic factors. As both free ribonucleotides and polymerized single-stranded RNA chains, ribonucleotides are highly charged with phosphate, and this genetic system is extremely vulnerable to disruption by a large number of electrostatic forces, and primarily by cationic metals such as aluminum. Aluminum has been shown by independent researchers to be particularly genotoxic to the genetic apparatus, and it has become reasonably clear that aluminum disturbs genetic signaling programs in the CNS that bear a surprising resemblance to those observed in Alzheimer's disease (AD) brain. This paper will focus on a discussion of two molecular-genetic aspects of aluminum genotoxicity: (1) the observation that micro-RNA (miRNA)-mediated global gene expression patterns in aluminum-treated transgenic animal models of AD (Tg-AD) strongly resemble those found in AD; and (2) the concept of "human biochemical individuality" and the hypothesis that individuals with certain gene expression patterns may be especially sensitive and perhaps predisposed to aluminum genotoxicity.

Dysphagia in Alzheimer's disease

OBJECTIVE

To investigate electrophysiological parameters of swallowing in all stages of Alzheimer's disease.

METHODS

Forty Alzheimer's disease patients, 20 age-matched normal controls and 20 young normal controls were included. Dysphagia limit (DL) and sequential water swallowing (SWS) tests were performed. Cardiac rhythm, respiration and sympathetic skin responses were concomitantly recorded.

RESULTS

Dysphagia was found in 30/40 (75%) of Alzheimer's disease patients. Mean volume at the DL test was significantly reduced (16.5±1.0mL) in the Alzheimer's disease group. Swallowing and apnea times in the SWS test were significantly prolonged in elderly controls, but even longer in Alzheimer's disease patients.

CONCLUSIONS

Alzheimer's disease patients had electrophysiological features of dysphagia, even in the early period of disease. The cortical involvement and severity of cognitive disorder can increase swallowing problems, but subclinical signs of dysphagia may be observed even in patients with mild or moderate Alzheimer's disease.

[Eye contact effects: A therapeutic issue?]

INTRODUCTION

The perception of a direct gaze - that is, of another individual's gaze directed at the observer that leads to eye contact - is known to influence a wide range of cognitive processes and behaviors. We stress that these effects mainly reflect positive impacts on human cognition and may thus be used as relevant tools for therapeutic purposes.

OBJECTIVES

In this review, we aim (1) to provide an exhaustive review of eye contact effects while discussing the limits of the dominant models used to explain these effects, (2) to illustrate the therapeutic potential of eye contact by targeting those pathologies that show both preserved gaze processing and deficits in one or several functions that are targeted by the eye contact effects, and (3) to propose concrete ways in which eye contact could be employed as a therapeutic tool.

DISCUSSION

(1) We regroup the variety of eye contact effects into four categories, including memory effects, activation of prosocial behavior, positive appraisals of self and others and the enhancement of self-awareness. We emphasize that the models proposed to account for these effects have a poor predictive value and that further descriptions of these effects is needed. (2) We then emphasize that people with pathologies that affect memory, social behavior, and self and/or other appraisal, and self-awareness could benefit from eye contact effects. We focus on depression, autism and Alzheimer's disease to illustrate our proposal. To our knowledge, no anomaly of eye contact has been reported in depression. Patients suffering from Alzheimer disease, at the early and moderate stage, have been shown to maintain a normal amount of eye contact with their interlocutor. We take into account that autism is controversial regarding whether gaze processing is preserved or altered. In the first view, individuals are thought to elude or omit gazing at another's eyes while in the second, individuals are considered to not be able to process the gaze of others. We adopt the first stance following the view that people with autism are not interested in processing social signals such as gaze but could do so efficiently if properly motivated. For each pathology we emphasize that eye contact could be used, for example, to enhance sensitivity to bodily states, thus improving emotional decision making (in autism); to lead to more positive appraisal of the self and others (in depression); to improve memory performances (in Alzheimer disease) and, more generally, to motivate the recipient to engage in the therapeutic process. (3) Finally we propose two concrete ways to employ eye contact effects as a therapeutic tool. The first is to develop cognitive-behavioral tools to learn and/or motivate the recipient to create frequent and prolonged eye contact periods. The second is to raise awareness among caregivers of the beneficial effects of eye contact and to teach them the way to use eye contact to reach its optimum effects. Future investigations are however needed to explore the ways in which eye contact effects can be efficiently integrated in therapeutic strategies, as well as to identify the clinical populations that can benefit from such therapeutic interventions.

[Not Available]

In France, few studies have investigated the experience of home caregivers with elderly people suffering from Alzheimer's disease or alcoholic behavior. The aim of this study was to describe caregivers' understanding of these disorders to identify their difficulties and satisfactions in relation to their role. Seventeen social care workers were interviewed and the content was analysed using a general inductive approach. Regarding misuse or abuse of alcohol, they expressed a feeling of helplessness, and put forth their experience and skills to communicate with the receiver of care. Concerning Alzheimer's disease, they expressed worries regarding its progression They identified themselves with the elder's anxiety, which induced fears regarding their own old age. All of them were satisfied by the care they provided and by the possibility of acquiring experience. Results could be of use in supporting clinical preventive actions for professional home caregivers dealing with these two disorders that can occur in the course of the ageing process.

From steroid hormones to depressive states and senile dementias: New mechanistic, therapeutical and predictive approaches

The discovery of "neurosteroids" leads to new descriptions and treatments of neuro-pathological pathologies. 3-β-methoxy-pregnenolone may be used to treat alterations of neuro-traumatisms and cerebral lesions associated with depressive states. Protein FKBP52 is involved in the dysfunction of the tau protein in Alzheimer's disease and senile dementias. In all cases, neuronal microtubules are involved in the mechanism of lesions and their repair.

[Mnesic disorders caused by left temporal gliomas]

Episodic memory disorders are frequent in patients with temporal lesion. Verbal or visuo-spatial memory disorders depend on the location and the lateralization of the lesion. These disorders are well described in temporal epilepsy but rarely in population with cerebral tumor and especially not specifically focus on temporal glioma. The purpose of this study was to describe neuropsychological examination in patient with temporal glioma in the database of the regional memory centre of Besançon. Four patients were identified (all right-handed and with a left temporal glioma). Verbal episodic memory impairment and auditory-verbal short-term memory impairment were observed. One patient had also visual memory disorders. Therefore, further investigations showed an associated Alzheimer's disease. This finding modified the clinical management of this patient. Extensive neuropsychological assessment should be systematic initially to seek an associated pathology, especially in elderly patients, if the cognitive profile is unusual, during the follow-up to better understand cognitive evolution and the effect of therapies on cognition.

[Injectable preparation of labeled leucine with the carbon 13 for a clinical research program on the Alzheimer disease: pharmaceutical control of raw materials and the finished product and stability study]

INTRODUCTION

The L-leucine labeled (L-[U-(13)C] Leu) is a stable isotopic tracer administered by parenteral route within the framework of a new clinical research program concerning the diagnosis of the Alzheimer's disease. To meet regulatory requirements and have ready to use solution with an expiration date, a pharmaceutical control of raw materials and the finished product followed by a stability study were realised.

MATERIALS AND METHOD

After the pharmaceutical control of raw materials, the solution of L-[U-(13)C] Leu was prepared according to the good practices preparation. Prepared bottles were stored for 1 year of a share in a climatic chamber (25 °C±2 °C) and the other in a refrigerator (5 °C±3 °C). To assess stability, the physicochemical controls (pH, osmolality, sub-visible particles, L-[U-(13)C] Leu concentration, sodium concentration, isotopic enrichment) and microbiological (bacterial endotoxin and sterility) were performed at regular intervals for 1 year.

RESULTS

Neither significant decrease of L-[U-(13)C] Leu concentration and sodium concentration nor pH and osmolality variation were observed for 1 year. Isotopic enrichment higher than 99.9% reflected the stability of labelling of L-leucine molecule. The sub-visible particles, the bacterial endotoxin and sterility were in accordance with the European pharmacopoeia attesting limpidity, apyrogenicity and sterility of this injectable preparation.

DISCUSSION AND CONCLUSION

The injectable preparation of L-[U-(13)C] Leu was stable after 1 year for two preservation conditions, ensuring to safety for administration for human within the framework of this clinical research.

[Changes in olfaction during ageing and in certain neurodegenerative diseases: up-to-date]

Olfaction is a complex sensory system, and increasing interest is being shown in the link between olfaction and cognition, notably in the elderly. In this literature review, we revisit the specific neurophysiological features of the olfactory system and odorants that lead to a durable olfactory memory and an emotional memory, for which the implicit component produces subconscious olfactory conditioning. Olfaction is known to affect cognitive abilities and mood. We also consider the impairment of olfactory function due to ageing and to neurodegenerative diseases, in particular Alzheimer's disease and Parkinson's disease, through anatomopathological changes in the peripheral and central olfactory structures. The high frequency of these olfactory disorders as well as their early occurrence in Alzheimer disease and Parkinson disease are in favour of their clinical detection in subjects suffering from these two neurodegenerative diseases. Finally, we analyse the impact of olfactory stimulation on cognitive performance and attention. Current observational data from studies in elderly patients with Alzheimer-type dementia are limited to multiple sensory stimulation methods, such as the Snoezelen method, and aromatherapy. These therapies have shown benefits for dementia-related mood and behaviour disorders in the short term, with few side effects. Since olfactory chemosensory stimulation may be beneficial, it may be proposed in patients with dementia, especially Alzheimer-type dementia, as a complementary or even alternative therapy to existing medical strategies.

[Clinical presentation of Moroccan cases with Alzheimer's disease]

INTRODUCTION

The diagnostic approach for Alzheimer's disease is based on the presence of cerebral atrophy combined with the score of the mini-examination of the mental state. In this context, this study was conducted to assess the correlation between imaging and neuropsychological testing for cases of early-onset and late-onset Alzheimer's disease.

AIM OF THE STUDY

Analysis of the clinical and paraclinical aspects of Moroccan cases with Alzheimer's disease.

METHODS

Seventeen sporadic cases and 8 family cases were seen at the memory clinic of the Neurology Department of the University of Casablanca Ibn Rochd Hospital. A family history was obtained through a clinical interview of the patient and a yes or no self-reporting questionnaire from the guardian or other family member. The disease was considered familial if at least one additional first degree relative suffered from early-onset AD-type dementia. All patients underwent standard somatic neurological examination, cognitive function assessment, brain imaging and laboratory tests. Written consent was obtained from the patients and their guardians prior to the study.

RESULTS

In our study of 25 individuals, the observed mean age of AD patients was 64.52 ± 9.30 and we observed a slight female predominance (56% versus 44%). In addition, we found a prevalence of AD of approximately 20%, increasing with age, in the population below 60 years of age. Approximately half of our patients (48%) had a score lower than 10 and were affected by severe insanity, while 28% were affected by moderate severe insanity and 24% were light to moderately insane. Twenty-five patients underwent neuroimaging, 18 of whom were assessed by MRI, while 7 were assessed by CT. All patients had hippocampal atrophy, which progressed to affect others brain regions. The blood tests showed no abnormalities in the 25 enrolled AD cases.

DISCUSSION

Age is undoubtedly the main risk factor for AD; this is also the true for our cases where advanced age was responsible for the exponential increase of the disease's frequency; it reached a peak in the age group of 60-69 years. The AD diagnosis approach is based on the presence of cerebral atrophy combined with the score of the mini-examination of the mental state (MMSE). In our study, in addition to the MMSE, depending on the level of education, the clinician used other tests that do not necessarily require a level of education such as the BEC96, visual short-term or digital memory assessment, work memory assessment, language assessment test (DO80) and apraxia. Neuropsychological examination of the cases with a score of less than 10 showed severe cognitive impairment. The cases presented memory and language impairments, aphasia, visual spatial disorientation, decreased autonomy, executive dysfunction and praxis deficits, all major causes of severe dementia. Neuroimaging revealed hippocampal and cortical atrophy. Correlated with the other studies that aimed to establish links between brain alterations and neuropsychological disorders, we can conclude that a higher level of atrophy reflects a decrease in neuropsychological performance.

[Awareness disorders in Alzheimer's disease and in mild cognitive impairment]

INTRODUCTION

Awareness disorders in Alzheimer's disease still remains unclear despite much research regarding this phenomenon. Papers report various and contrasted results with varying frequency from one study to another. Hence, the interest in awareness in Alzheimer's disease remains limited. Nevertheless, this symptom is closely associated with caregivers' burden and increases the patient's dependency, since the patient is unable to avoid dangers, requiring some care services or institutionalization The purpose of this current review is to recall the main neuro-anatomical and theoretical basis of awareness disorders, and to highlight the recent findings in Alzheimer's disease and in its pre-clinical stages.

METHOD

With this in mind, we have conducted a non-exhaustive search using the pubmed online database to collect the most important reviews and the most recent findings regarding awareness disorders in Mild Cognitive Impairment (MCI) and/or in Alzheimer's disease.

LITERATURE FINDINGS

In Alzheimer's disease, the links between awareness disorders and other variables, such as severity of dementia or depression, change from one study to the other and do not permit one to understand whether unawareness is an intrinsic or extrinsic reaction to the pathological process itself. Recent results suggest executive, cognitive and behavioral correlates more than psychopathological correlates, although the latter cannot be excluded. In Mild Cognitive Impairment, studies show varied results. Some studies report that patients suffering from Mild Cognitive Impairment can be compared to healthy control subjects and both groups have better awareness than patients with Alzheimer's disease. However, other studies show contrary results and awareness disorders might be a predictor of conversion from Mild Cognitive Impairment to dementia, as with apathy, in which the ability to cope with difficulties represents one of the main features.

DISCUSSION

These controversial results are due to the heterogeneity of Alzheimer patients and in particular of MCI patients, but also to various conceptions of awareness disorders in Alzheimer's disease; none of them, however, taking into account all its diversity and complexity. Thus, neurological approaches underline neuropsychological dysfunctions linked to right frontal and/or hemispheric damage but are based on brain injury or strokes, which are events that differ greatly from a neurodegenerative disease involving progressive cognitive, emotional and social disturbances. Psychiatric approaches have taken into account the various aspects of insight, which before were often forbidden and reduced to a categorical point of view, and so could contribute to a better understanding of awareness disorders in Alzheimer's disease. However, these aspects have been conceptualized for psychiatric patients, suffering from positive symptoms, where compliance in treatment is the central key. Insight in neurological diseases is more focused on negative symptoms and generally concerns a basic perception of impairments in mainly cognitive domains. Moreover, modeling has often opposed neurological and psychological mechanisms, so awareness disorders are out of scope of a primary and secondary symptomatology. Although some authors have proposed to take into account these two mechanisms (unawareness and denial), clinical practice has shown that it was impossible to distinguish them both. Finally, some social cognitive approaches are able to demonstrate that there is no correlation between severity of dementia and awareness disorders. Nevertheless, the Self-concept, underlying this point of view, does not permit distinguishing neuropsychological from psycho-social factors. Moreover, only one evaluation tool based on Self-modeling in Alzheimer's disease exists, and to conceptualize Self in a specific pathology does not permit the comparison of this pathology to others or to healthy control subjects. So, the authors present the multidimensional model proposed by Clare et al., and some perspectives to stimulate future research, and perform potential meta-analyses.

[Obstructive sleep apnea syndrome: a cause of cognitive disorders in the elderly?]

Obstructive sleep apnea syndrome is a chronic disease characterized by repeated upper airway obstructions during sleep, resulting in fragmented sleep with arousals, nocturnal intermittent hypoxemia and diurnal dysfunctions. Despite its high prevalence in elderly, sleep apnea syndrome seems to be underestimated and difficult to be recognized because of the lack of clinical symptoms specificity in this population. Among the numerous consequences of the obstructive sleep apnea syndrome, cognitive impairment prevails on the attention, executive functions and memory. Neuroimaging studies in human and experimental models allowed to highlight neural correlates of these cognitive dysfunctions in obstructive sleep apnea syndrome. The obstructive sleep apnea syndrome with cognitive impairment shares some features with Alzheimer's disease, involving genetic predisposition ApoE4, hippocampus and synaptic plasticity abnormalities. In this context, the question arises whether obstructive sleep apnea syndrome is a possible etiological or aggravating factor of cognitive decline in elderly with mild cognitive impairment or Alzheimer's disease. Although there are conflicting results in studies evaluating therapeutic efficiency of continuous positive air pressure, obstructive sleep apnea syndrome seems nevertheless as a correctable factor, at least for its impact on some cognitive consequences. Looking for sleep apnea syndrome in elderly with cognitive decline should be considered in a global, diagnosis and therapeutic management.

Influence of cognitive impairment on the management of ischaemic stroke

BACKGROUND

Because of ageing of the population, it is more and more frequent to treat ischaemic stroke patients with pre-stroke cognitive impairment (PSCI). Currently, there is no specific recommendation on ischaemic stroke management in these patients, both at the acute stage and in secondary prevention. However, these patients are less likely to receive treatments proven effective in randomised controlled trials, even in the absence of contra-indication.

OBJECTIVE

To review the literature to assess efficacy and safety of validated therapies for acute ischaemic stroke and secondary prevention in PSCI patients.

RESULTS

Most randomised trials did not take into account the pre-stroke cognitive status. The few observational studies conducted at the acute stage or in secondary prevention, did not provide any information that the benefit could be either lost or replaced by harm in the presence of PSCI.

CONCLUSIONS

There is no reason not to treat ischaemic stroke patients with PSCI according to the currently available recommendations for acute management and secondary prevention. Further observational studies are needed and pre-stroke cognition should be taken into account in future stroke trials.

[Evaluation of temporality semantic knowledge in normal aging and in mild and moderate stages of Alzheimer's disease]

OBJECTIVE

Episodic and semantic processes are involved in temporality used in daily life. Episodic memory permits one to place an event on the time axis, while semantic memory makes us aware of the time segmentation and its symbolic representation. Memory of the knowledge connected to the passing of time is materialized on the calendar and can be seen symbolically on the dial of a clock. In AD, semantic memory processes are preserved longer than processes related to episodic memory. We wonder whether the specific field of knowledge about time is altered during AD.

METHODOLOGY

We validated a specific evaluation with a control group (354 healthy subjects). Then we applied this battery to assess AD patients to appreciate the feasibility of this tool for this population. We then compared 22 AD patients with a control group matched for age, sex and educational level. Our clinical scale of temporal semantic knowledge consists of four parts: (a) hour reading with a.m. and p.m. hours; (b) using a clock: 12 clock faces with the hour numbers already placed: the patient draws hour and minute hands for various hours; (c) temporal segmentation: exploration of the knowledge on daytime scale and of the calendar; (d) time duration estimation: calculate how long the interview has lasted after indicating the time of its beginning and its end, then the time between 10.40 to 12.00.

RESULTS

While age and educational level had an influence on all the scores, in the two groups control and patients, gender did not. Temporal segmentation, independent of the cultural level, revealed the best acquired knowledge in our control population. All the scores differentiated patients from control subjects. The temporal semantic knowledge correlated with the AD severity seemed to be correlated with the attention, verbal comprehension, and some components of executive functions, but was not related to the clock drawing test result. Depression did not have any influence on this scale in our AD group.

DISCUSSION

The temporal semantic knowledge clinical scale shows differential alterations, notably in hour reading and using a clock, and less in temporal segmentation.

CONCLUSION

Temporal semantic knowledge is altered in AD. The diagnosis and follow-up of these alterations allow professionals and caregivers to consider adaptations of the patient's environment according to their needs.

[Dementia: Where are the Lewy bodies?]

Dementia with Lewy bodies (DLB) is the second cause of degenerative dementia in autopsy studies. In clinical pratice however, the prevalence of DLB is much lower with important intercenter variations. Among the reasons for this low sensitivity of DLB diagnosis are (1) the imprecision and subjectivity of the diagnostic criteria; (2) the underestimation of non-motor symptoms (REM-sleep behavior disorder, dysautonomia, anosmia); mostly (3) the nearly constant association of Lewy bodies with Alzheimer's disease pathology, which dominates the clinical phenotype. With the avenue of targeted therapies against the protein agregates, new clinical scales able to apprehend the coexistence of Lewy pathology in Alzheimer's disease are expected.

Aphasia(s) in Alzheimer

Language disorders of degenerative origin are frequently tied to Alzheimer disease (AD) the different variants of which can result in primary and secondary aphasia syndromes. More specifically, Alzheimer pathology can primarily erode frontal, temporal or parietal language cortices resulting in three genuine AD language variants which account for about 30% of primary degenerative aphasias. Likewise, it can spread from non-language to language cortices leading to secondary language disorders like in typical amnesic AD and in several atypical AD variants. This paper reviews the whole set of AD variants by characterising their impact on the neural language system and on linguistic functioning. It also provides cues for diagnostic strategies which are essential for linguistic, syndromic and nosological patient classification, for adequate clinical follow-up and for guiding language rehabilitation. Such diagnostic approaches, founded on detailed linguistic phenotyping while integrating anatomical and neuropathological findings, also represent a crucial issue for future drug trials targeting the physio-pathological processes in degenerative aphasias.

Towards an earlier diagnosis of Alzheimer's disease presenting with visuospatial disorders (posterior cortical atrophy)

Progressive visual complaints related to visuospatial disorders, and less often to visuoperceptual disorders, may be the presenting and isolated manifestation of a focal degeneration in the posterior cortical areas, called posterior cortical atrophy (PCA). PCA is a clinical syndrome corresponding to a focal variant of Alzheimer's disease in 80% of cases. The predominant dysfunction in the occipitoparietal pathways results in predominant visuospatial disorders, manifesting primarily as dorsal simultanagnosia, alone or associated with other symptoms of Balint's syndrome. PCA is rare and affects young patients who are fully aware of their deficits. Diagnosis of PCA is often delayed, due to insidious onset and development of symptoms, and to poor awareness of the condition in the medical community. An earlier diagnosis requires both better knowledge of PCA among ophthalmologists and neurologists and better recognition of visual complaints, leading to simple bedside tasks that can tackle the syndrome.

[Genetic aspects of Alzheimer's disease (Review)]

Alzheimer's disease is a degenerative brain disorder, which concerns memory, cognition and behavior pattern. Its etiology is unknown, it is characterized by typical histological lesions: senile plaques and neuro-fibrillary tangles. Alzheimer's disease is a multifactorial pathology, characterized by interactions between genetic and environmental factors. Genetic factors concern first of all the exceptional monogenic forms, characterized by early onset (<60 years), autosomal dominant forms. Mutations of the genes coding for amyloid-ß precursor protein or preselinins 1 and 2 are involved. The much more frequent sporadic forms also have genetic factors, the best studied being the apolipoprotein E4 coding allele and some more recent genotypes which will be mentioned. No causal, only symptomatic treatments are available.

Magnetic resonance imaging for diagnosis of early Alzheimer's disease

A major challenge for neuroimaging is to contribute to the early diagnosis of Alzheimer's disease (AD). In particular, magnetic resonance imaging (MRI) allows detecting different types of structural and functional abnormalities at an early stage of the disease. Anatomical MRI is the most widely used technique and provides local and global measures of atrophy. The recent diagnostic criteria of "mild cognitive impairment due to AD" include hippocampal atrophy, which is considered a marker of neuronal injury. Advanced image analysis techniques generate automatic and reproducible measures both in the hippocampus and throughout the whole brain. Recent modalities such as diffusion-tensor imaging and resting-state functional MRI provide additional measures that could contribute to the early diagnosis but require further validation.

Preclinical trials in autosomal dominant AD: implementation of the DIAN-TU trial

The Dominantly Inherited Alzheimer's Network Trials Unit (DIAN-TU) was formed to direct the design and management of interventional therapeutic trials of international DIAN and autosomal dominant Alzheimer's disease (ADAD) participants. The goal of the DIAN-TU is to implement safe trials that have the highest likelihood of success while advancing scientific understanding of these diseases and clinical effects of proposed therapies. The DIAN-TU has launched a trial design that leverages the existing infrastructure of the ongoing DIAN observational study, takes advantage of a variety of drug targets, incorporates the latest results of biomarker and cognitive data collected during the observational study, and implements biomarkers measuring Alzheimer's disease (AD) biological processes to improve the efficiency of trial design. The DIAN-TU trial design is unique due to the sophisticated design of multiple drugs, multiple pharmaceutical partners, academics servings as sponsor, geographic distribution of a rare population and intensive safety and biomarker assessments. The implementation of the operational aspects such as home health research delivery, safety magnetic resonance imagings (MRIs) at remote locations, monitoring clinical and cognitive measures, and regulatory management involving multiple pharmaceutical sponsors of the complex DIAN-TU trial are described.