Relationship of frontal lobe dysfunction and aberrant motor behaviors in patients with Alzheimer's disease

Mental health among centenarians living in Switzerland

BACKGROUND

Given the increasing number of people achieving exceptionally long lifespans, there is an urgent need for a better understanding of mental health in centenarians. This study aimed to understand the prevalence of mental health conditions-depressive symptoms, anxiety, sleep disturbances, disinhibition, and aberrant motor behaviour-among centenarians in Switzerland.

METHODS

Data were collected from N = 169 participants via telephone interviews or paper questionnaires, either directly from centenarians or through proxy informants. Half the data were collected during a period when protective measures were imposed due to the COVID-19 pandemic, and half were collected after the measures were lifted.

RESULTS

Mental health conditions were prevalent in our sample, particularly depressive symptoms (44.51%) and anxiety (42.17%). Significant positive associations were found between depressive symptoms and anxiety, and between disinhibition and aberrant motor behaviour. Furthermore, we identified statistical predictors for the occurrence of mental health conditions. Notably, institutionalised living increased the odds of depressive symptomatology, while those with higher education levels or an absence of cognitive impairment experienced more sleep disturbances. Finally, cognitive impairment was linked to increased disinhibition and aberrant motor behaviour.

CONCLUSIONS

The high prevalence of mental health conditions underscores the need for proactive mental health care strategies in advanced old age. Moreover, it is vital to consider the interconnected nature of mental health conditions and to prioritise vulnerable groups, such as centenarians in institutional settings.

The Associations Between Neuropsychiatric Symptoms and Cognition in People with Dementia: A Systematic Review and Meta-Analysis

Most people with dementia experience neuropsychiatric symptoms (NPS), including anxiety, depression or disinhibition. There is growing interest in the relationship between NPS and cognitive impairment, but data is still limited. This study aimed to investigate the specific associations between NPS and cognition in people with dementia. MEDLINE, EMBASE and PsycINFO were searched for published, peer-reviewed studies of associations between at least one NPS and one cognitive ability in people with dementia. The quality of the studies was assessed with the NIH National Heart, Lung and Blood Institute's quality assessment tools. A meta-analysis was conducted using Robumeta package for R. Ninety studies were included. We found significant associations between NPS, global cognition and cognitive domains, e.g. apathy was associated with global cognitive and memory impairment; dysphoria was associated with worse attention; delusions with executive dysfunction. Increased NPS in people with dementia are associated with worse cognitive performance. There were few studies looking at associations between some neuropsychiatric clusters and cognitive abilities, and there was little research on causal relationships. Our review was limited by the inclusion of studies that reported associations in specific formats, and most included people with a diagnosis of Alzheimer's disease (AD). However, given the large number of studies, this is unlikely to have biased results. More research is needed that includes diverse people with different dementia syndromes. Registration: PROSPERO 2020 CRD42020165565.

What evidence is there for implicating the brain orexin system in neuropsychiatric symptoms in dementia?

Neuropsychiatric symptoms (NPS) affect people with dementia (PwD) almost universally across all stages of the disease, and regardless of its exact etiology. NPS lead to disability and reduced quality of life of PwD and their caregivers. NPS include hyperactivity (agitation and irritability), affective problems (anxiety and depression), psychosis (delusions and hallucinations), apathy, and sleep disturbances. Preclinical studies have shown that the orexin neuropeptide system modulates arousal and a wide range of behaviors via a network of axons projecting from the hypothalamus throughout almost the entire brain to multiple, even distant, regions. Orexin neurons integrate different types of incoming information (e.g., metabolic, circadian, sensory, emotional) and convert them into the required behavioral output coupled to the necessary arousal status. Here we present an overview of the behavioral domains influenced by the orexin system that may be relevant for the expression of some critical NPS in PwD. We also hypothesize on the potential effects of pharmacological interference with the orexin system in the context of NPS in PwD.

Brain mechanisms underlying neuropsychiatric symptoms in Alzheimer's disease: a systematic review of symptom-general and -specific lesion patterns

Neuropsychiatric symptoms (NPSs) are common in patients with Alzheimer's disease (AD) and are associated with accelerated cognitive impairment and earlier deaths. This review aims to explore the neural pathogenesis of NPSs in AD and its association with the progression of AD. We first provide a literature overview on the onset times of NPSs. Different NPSs occur in different disease stages of AD, but most symptoms appear in the preclinical AD or mild cognitive impairment stage and develop progressively. Next, we describe symptom-general and -specific patterns of brain lesions. Generally, the anterior cingulate cortex is a commonly damaged region across all symptoms, and the prefrontal cortex, especially the orbitofrontal cortex, is also a critical region associated with most NPSs. In contrast, the anterior cingulate-subcortical circuit is specifically related to apathy in AD, the frontal-limbic circuit is related to depression, and the amygdala circuit is related to anxiety. Finally, we elucidate the associations between the NPSs and AD by combining the onset time with the neural basis of NPSs.

Neuropsychiatric Symptoms of Alzheimer's Disease in Down Syndrome and Its Impact on Caregiver Distress

BACKGROUND

Neuropsychiatric symptoms (NPS) are non-cognitive manifestations common to dementia and other medical conditions, with important consequences for the patient, caregivers, and society. Studies investigating NPS in individuals with Down syndrome (DS) and dementia are scarce.

OBJECTIVE

Characterize NPS and caregiver distress among adults with DS using the Neuropsychiatric Inventory (NPI).

METHODS

We evaluated 92 individuals with DS (≥30 years of age), divided by clinical diagnosis: stable cognition, prodromal dementia, and AD. Diagnosis was determined by a psychiatrist using the Cambridge Examination for Mental Disorders of Older People with Down's Syndrome and Others with Intellectual Disabilities (CAMDEX-DS). NPS and caregiver distress were evaluated by an independent psychiatrist using the NPI, and participants underwent a neuropsychological assessment with Cambridge Cognitive Examination (CAMCOG-DS).

RESULTS

Symptom severity differed between-groups for delusion, agitation, apathy, aberrant motor behavior, nighttime behavior disturbance, and total NPI scores, with NPS total score being found to be a predictor of AD in comparison to stable cognition (OR for one-point increase in the NPI = 1.342, p = 0.012). Agitation, apathy, nighttime behavior disturbances, and total NPI were associated with CAMCOG-DS, and 62% of caregivers of individuals with AD reported severe distress related to NPS. Caregiver distress was most impacted by symptoms of apathy followed by nighttime behavior, appetite/eating abnormalities, anxiety, irritability, disinhibition, and depression (R2 = 0.627, F(15,76) = 8.510, p < 0.001).

CONCLUSION

NPS are frequent and severe in individuals with DS and AD, contributing to caregiver distress. NPS in DS must be considered of critical relevance demanding management and treatment. Further studies are warranted to understand the biological underpinnings of such symptoms.

Neuropsychiatric symptoms and activities of daily living in Alzheimer's disease: ALSOVA 5-year follow-up study

BACKGROUND

Neuropsychiatric symptoms (NPSs) in Alzheimer's disease (AD) are related to activities of daily living (ADLs), but longitudinal studies are sparse.

OBJECTIVES

We investigated which NPSs were related to decline in instrumental ADLs (IADLs) and basic ADLs (BADLs) in a 5-year follow-up of individuals with AD.

METHODS

ALSOVA 5-year follow-up study data of 236 individuals with very mild or mild AD at baseline and their caregiver were analyzed. IADLs and BADLs were assessed with Alzheimer's Disease Cooperative Study ADL inventory, and NPSs with Neuropsychiatric Inventory at annual follow-up visits. Generalized estimating equations (GEEs) were used for longitudinal data analysis, and NPS-ADL networks were estimated to demonstrate symptom interactions.

RESULTS

Apathy [rate ratio (RR) 1.23, 95% CI 1.06-1.44, p = 0.007], aberrant motor behavior (RR 1.24, 95% CI 1.07-1.44, p = 0.005), and appetite disturbances (RR 1.22, 95% CI 1.06-1.41, p = 0.005) were related to impairment in BADLs, and the same symptoms (RR 1.13, 95% CI 1.07-1.21, p < 0.001; RR 1.13, 95% CI 1.07-1.20, p < 0.001; RR 1.14; 95% CI 1.08-1.21, p < 0.001, for apathy, aberrant motor behavior, and appetite disturbances, respectively), in addition to delusions (RR 1.09, 95% CI 1.03-1.15, p = 0.004), were related to IADL impairment. Symptom networks varied at different time points.

CONCLUSION

As AD progresses, common (apathy) and uncommon NPSs (aberrant motor behavior, appetite disturbances, delusions) seem to be related to ADLs through various symptom interactions. Previous literature suggests that frontal pathology could underlie these relationships.

Anosognosia in patients with Alzheimer's disease: current perspectives

Alzheimer's disease (AD) is a neurodegenerative disease characterised by neurocognitive impairments, especially memory impairment, as core symptoms linked to reductions in activities of daily life. As marginal symptoms, neuropsychiatric symptoms (NPSs) appear during the progressive course of the disease. A lack of self-awareness (anosognosia) of cognitive and functional impairments is often seen in patients with AD, and associations between anosognosia and other NPSs have been previously reported. To account for anosognosia pathogenesis neurocognitively, the cognitive awareness model (CAM) has been helpful for explaining the stream of events from sensory input to behavioural/affective and metacognitive outputs. According to CAM, there are three types of anosognosia: (i) primary anosognosia, (ii) executive anosognosia, and (iii) mnemonic anosognosia. These types of anosognosia are generated from different neurocognitive modulations leading to metacognitive outputs or behavioural/affective regulations. Primary anosognosia is considered to be caused by deficits in the metacognitive awareness system (MAS). While preserved MAS function is associated with milder depression and anxiety in AD, a severer depressive mood in patients with mild AD can inversely cause self-underestimation. The modulation of executive anosognosia is thought to be associated with dangerous/disinhibition behaviours and apathy among NPS sub-symptoms, via impairments of comparator mechanism (Cm) within the central executive system. Other neurobehavioral reactions linked to self-awareness include 'denying' and 'confabulation', and each of these reactions is thought to be affected by the MAS and a Cm. Denial of one's own memory impairments appears as a defensive reaction to protect against dysphoric feelings, and the confabulatory comment is instantly reaction constructed by fabrications according to misinterpretations of memory information about oneself. Similarly, the innovative development of a theoretical model (CAM) has contributed to explaining the mechanism of anosognosia and some neurobehavioral outputs from a neurocognitive perspective.

Effects of neuropsychiatric symptoms of dementia on reductions in activities of daily living in patients with Alzheimer's disease

AIM

In patients with Alzheimer's disease (AD), cognitive impairments cause a progressive reduction in Activities of Daily Living (ADL). Neuropsychiatric symptoms (NPS) also appear in most patients; however, the association between NPS and reductions in ADL remains unclear. The present study evaluated whether NPS influence such reductions using two different ADL measures in patients with AD.

METHODS

Among 546 consecutive outpatients who visited the memory clinic at the Jikei University Kashiwa Hospital, we recruited 208 patients with AD and investigated the correlations between either the Physical Self-Maintenance Scale (PSMS) score or the Instrumental ADL (IADL) level, and each of the Behavioral Pathology in AD (Behave-AD) subscales. To clarify the causal relationships of these correlations, we then verified the associations between statistically significant demographic variables and the Behave-AD subscales as well as the two ADL scales (PSMS score and IADL percentage) using a general linear model.

RESULTS

Neither the PSMS nor the IADL results were significantly influenced by the aberrant motor behaviors score. However, the IADL was significantly influenced by the Mini-Mental State Exam (MMSE) score. Furthermore, diurnal rhythm disturbances and the interaction between diurnal rhythm disturbances score and the MMSE score significantly influenced the PSMS results.

CONCLUSION

Basic ADL reductions may be influenced by diurnal rhythm disturbances, in addition to cognitive impairments in patients with AD. Furthermore, the interaction between the diurnal rhythm disturbances score and cognitive function may also influence basic ADL. Geriatr Gerontol Int 2020; ••: ••-••.

Supporting ethical use of electronic monitoring for people living with dementia: Social work's role in assessment, decision-making, and review

Walking outdoors supports health and well-being, but some people living with dementia are at increased risk of getting lost and of harm while missing. Electronic monitoring can potentially play an important preventative role by enabling the person's location to be continuously monitored by caregivers. However, there are considerable ethical concerns arising from electronic monitoring. This paper explores these thematically, drawing attention to its implications for autonomy and liberty; privacy; dignity; the rights and needs of caregivers and families; beneficence and nonmaleficence. Following from this, key questions for consideration in social work assessment are identified. The ethical issues necessitate assessment of the person's unique circumstances and preferences and that of their caregivers, and careful ethical deliberation in decision-making. Social work can play an important role in facilitating inclusive assessment and decision-making, leading to consensus on intervening with electronic monitoring. The need for the ongoing review following implementation is discussed to track whether decisions need modification in light of the experience of usage. In conclusion, while legislative instruments and professional codes of ethics frame social work practice responses, there is need for a nuanced debate about ethical use of electronic monitoring and specific guidance to inform assessment, decision-making, and review.

Longitudinal Neuropsychiatric Predictors of Death in Alzheimer's Disease

Characteristics associated with life expectancy in Alzheimer's disease (AD) are still far from known. Here we aimed at examining the ability of baseline/longitudinal clinical variables to predict time to death. One-hundred fifty AD outpatients underwent diagnostic, neuropsychiatric, and functional assessment at baseline (when ApoE ɛ4 was also investigated) and at each subsequent annual visit. A random effects joint modeling approach was used to simultaneously model the baseline and longitudinal trajectory of each factor and predict the time to death, adjusting for demographic covariates. An ancillary analysis of ApoE ɛ4 status as a predictor was also conducted. Kaplan-Meier survival curves were constructed to elucidate the relationship between each factor and the estimated probability of death over time. Shorter survival was associated with male gender, higher education, older age, lower cognition, and worse functioning in daily life, but not ApoE ɛ4 status. Longitudinal trajectories increased predictive power over using just baseline levels highlighting apathy, and secondarily aberrant motor behaviors and sleep disorders, as a highly reliable predictor for mortality. Apathy was the strongest neuropsychiatric predictor of time to death, which supports its role in the pathogenesis of the disorder. An increased knowledge of factors modulating survival in AD is a strategic prerequisite to plan therapeutic interventions.

Supporting people with dementia to walkabout safely outdoors: development of a structured model of assessment

People with dementia while missing are at risk of harm including death. Yet, welfare concerns arise when freedom to walkabout outdoors is restricted and in particular, getting lost is a risk factor for admission to long-term care. Accurate methods of assessing the risks posed to community-dwelling people with dementia from getting lost are needed to ensure intervention is proportionate. Currently available assessment tools focus upon the identification of dementia-related changes in a person's walking behaviour, traditionally referred to as 'wandering'. 'Wandering' and getting lost are conceptually distinct; measures of 'wandering' are not sufficient to support the assessment of risk while walking outdoors. The objective of this study was to develop an assessment schedule that can evaluate safety in community-dwelling people with dementia who walkabout outdoors. A structured assessment schedule was generated from research on the aetiology of getting lost, a review of existing assessment tools, an observational study of incidents of getting lost and qualitative data from families experiencing this issue. A content validity study was then undertaken with a panel of 17 health and social care practitioners and researchers in the field. A schedule of 7 domains and 38 items was generated, 33 of which were deemed valid by the expert panel. Panel feedback suggests the schedule needs to be used flexibly to reflect an individual's unique living circumstances. Reflecting the complex aetiology of getting lost, considerable challenges exist when assessing risk in this field. The implications of this study for practitioners are discussed with reference to the merits of narrative and structured models of assessment, and the balance between objective safety and subjective well-being that is required when making decisions about intervention. The direction of further research is examined as a means of supporting professional assessment of this complex issue.

French Validation of the Revised Algase Wandering Scale for Long-Term Care

OBJECTIVES

The aim of this study was to create a French equivalent of the revised Algase wandering scale for long-term care (RAWS-LTC).

METHODS

The RAWS-LTC French version (F-RAWS-LTC), Mini-Mental State Examination, and Neuropsychiatric Inventory were administered to a sample of 100 institutionalized patients from 12 specialized homes.

RESULTS

The mean of the overall F-RAWS-LTC was 2.32 (standard deviation [SD]=0.74, range 1-4), and the mean of each subscale was 2.48 for persistent walking, 1.62 for eloping behavior, and 2.30 for spatial disorientation. The correlation between the overall F-RAWS-LTC and each subscale was between 0.73 (for Spatial Disorientation) and 0.87 (for Persistent Walking). The correlation between the degree of behavioral disturbances and the overall F-RAWS-LTC is 0.42, and the correlation with the cognitive impairment is 0.50. Differences between the wanderers and nonwanderers are significant for the overall F-RAWS-LTC and for all the subscales.

DISCUSSION

Data demonstrate the statistical validity of the F-RAWS-LTC.

Dementia, walking outdoors and getting lost: incidence, risk factors and consequences from dementia-related police missing-person reports

OBJECTIVES

To estimate incidence, identify consequences and potential risk factors for harm in people with dementia who got lost in one UK policing region.

METHODS

In a retrospective observational study, data were extracted from missing-person records over a four-year period in one UK policing region (population of 2.1 million).

RESULTS

Two hundred and eighty-one incidents of getting lost were identified. Incidence of getting lost was estimated at 0.5% of the regional dementia population. Fifty-nine percent of reports came from domestic settings, 29% from care homes/hospitals, and 12% on excursions from home. Five percent (n = 15) sustained significant harm, including two deaths. Average age was 78 years (SD 8.3). Harm was associated with older age (mean difference 6.16 years, CI 1.86 to 10.46, p = 0.005, t = 2.82), length of time missing (Mdn time 2.48 hours; IQR 0.97 to 9.45, p = 0.02), and season (9% winter, 2% summer, p = 0.006). The length of time missing increased with delays in reporting to police (r = 0.15, p = 0.018), getting lost at night (Mdn time 1.70 hours, IQR 0.52-3.32, p = 0.028), driving themselves (Mdn time 2.45 hours, IQR 0.42-2.00, p = 0.001), and using public transport (Mdn 1.78 hours, IQR 1.07-3.92, p = 0.001).

CONCLUSION

Incidence in this study suggests getting lost is a low-frequency event for people with dementia but for a small minority, the risks are considerable. Exploratory analyses suggest individual and environmental factors increase the risk of harm. Suitable methods need to be developed to replicate these findings in larger prospective samples. A focus on the predictors of harm may aid development of assessment protocols to ensure intervention is proportionate.

Association between DNA Methylation of the BDNF Promoter Region and Clinical Presentation in Alzheimer's Disease

Background/Aims

In the present study, we examined whether DNA methylation of the brain-derived neurotrophic factor (BDNF) promoter is associated with the manifestation and clinical presentation of Alzheimer's disease (AD).

Methods

Of 20 patients with AD and 20 age-matched normal controls (NCs), the DNA methylation of the BDNF promoter (measured using peripheral blood samples) was completely analyzed in 12 patients with AD and 6 NCs. The resulting methylation levels were compared statistically. Next, we investigated the correlation between the DNA methylation levels and the clinical presentation of AD.

Results

The total methylation ratio (in %) of the 20 CpG sites was significantly higher in the AD patients (5.08 ± 5.52%) than in the NCs (2.09 ± 0.81%; p < 0.05). Of the 20 CpG sites, the methylation level at the CpG4 site was significantly higher in the AD subjects than in the NCs (p < 0.05). Moreover, the methylation level was significantly and negatively correlated with some neuropsychological test subscores (registration, recall, and prehension behavior scores; p < 0.05).

Conclusion

These results suggest that the DNA methylation of the BDNF promoter may significantly influence the manifestation of AD and might be associated with its neurocognitive presentation.

Plasma BDNF levels are correlated with aggressiveness in patients with amnestic mild cognitive impairment or Alzheimer disease

In the present study, we examined whether neuropsychiatric symptoms were correlated with plasma brain-derived neurotrophic factor (BDNF) levels as a state marker or were associated with the BDNF polymorphism Val66Met in patients with amnestic mild cognitive impairment (A-MCI) or Alzheimer disease (AD). One hundred and seventy-six outpatients with AD (n = 129) or A-MCI (n = 47) were selected and their plasma BDNF concentrations measured. Next, we investigated the correlation between the plasma BDNF level and the Behavioral Pathology in Alzheimer Disease (Behave-AD) subscale scores, which reflect neuropsychiatric symptoms. We also compared the plasma BDNF level and the Behave-AD subscale scores among the BDNF Val66Met genotypic groups. Among the seven Behave-AD subscale scores, aggressiveness was positively correlated with the plasma BDNF level (ρ = 0.237, P < 0.005), but did not differ significantly among the three BDNF Val66Met genotypic groups. The Behave-AD total and other subscale scores did not differ significantly among the BDNF Val66Met genotypic groups and were not associated with the plasma BDNF level. Moreover, the plasma BDNF level did not differ significantly among the three BDNF Val66Met genotypic groups or between patients with A-MCI and those with AD. The plasma BDNF level was robustly correlated with aggressiveness, implying that the plasma BDNF level might be useful as a behavioral state marker in patients with AD or A-MCI.

Neurobiology of neuropsychiatric symptoms in Alzheimer's disease: A critical review with a focus on neuroimaging

The objective of this critical review of the literature was to reveal the neural circuits involved in the occurrence of neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD) patients through the association of these symptoms with neuroimaging findings. The search for articles was performed on PUBMED from January 2000 to May 2013, using the key words: Dementia AND BPSD; Dementia AND Neuropsychiatric Symptoms; and Dementia AND Psychosis, Delusions, Hallucinations, Agitation, Depression, Anxiety, Apathy, Euphoria, Disinhibition, Irritability, Aberrant Motor Behavior, Sleep or Eating Disorders. Forty-six articles were reviewed and important contributions, especially regarding the psychopathological concepts discussed, were also considered even if not included in this time period. The available evidence suggests the three most relevant neurobiological models for neuropsychiatric symptoms in Alzheimer's disease are the frontal-subcortical circuits, the cortico-cortical networks, and the monoaminergic system. We discussed the association of the individual symptoms or syndromes with these models.

FAB-D: German version of the Frontal Assessment Battery

Executive dysfunction (ED) is a frequent consequence of neurological disorders, such as stroke, trauma or dementia, but also appears in normal aging. We developed a German version of the Frontal Assessment Battery (FAB-D), a short test which has previously been developed (Dubois et al., Neurology 55:1621-1626, 2000) to detect ED during bedside screening. A sample of 401 cognitively intact subjects aged 50-95 was tested with the FAB-D and several neuropsychological tests tapping executive functions, memory and calculation abilities. Aim of the study was to receive normative data for different age and educational groups, and to learn which tests predict performance on the FAB-D. We found clear effects of age and education; furthermore, FAB-D performance was predicted by other tests of executive functioning, but also by calculation and memory abilities. The present study reports data of healthy individuals and may be useful for comparing patients' performance with a normative sample.

Age-Related Association between Apolipoprotein E ε4 and Cognitive Function in Japanese Patients with Alzheimer's Disease

AIMS

In the present study, we investigated whether apolipoprotein E (APOE) polymorphisms influenced the cognitive function of Japanese patients with Alzheimer's disease (AD) at certain ages.

METHODS

Among 200 outpatients with dementia and amnestic mild cognitive impairment, 133 Japanese patients with AD were recruited and divided into two genotypic groups: APOE ε4 carriers and noncarriers. Then, we compared several neuropsychological test scores between the two genotypic groups for two different generations: 70s (70-79 years) and 80s (80-89 years).

RESULTS

The total Mini-Mental State Examination score (p < 0.05) and one of its subtest scores, the 3-stage command score (p < 0.01), were significantly lower for the ε4 carriers than for the noncarriers among patients in their 80s, but not among those in their 70s. The duration of illness differed significantly between the ε4 carriers and the noncarriers among subjects in their 80s but was not correlated with cognitive function.

CONCLUSION

The present results suggest that APOE may significantly influence comparatively simple memory processing in certain generations of Japanese patients with AD.

Association between brain-derived neurotrophic factor (BDNF) gene polymorphisms and executive function in Japanese patients with Alzheimer's disease

BACKGROUND

To address the functional roles of genetic polymorphisms of brain-derived neurotrophic factor (BDNF) in Alzheimer's disease (AD) from a neuropsychological aspect, we used a cross-sectional study design to investigate the association between novel single nucleotide polymorphisms (SNPs) of the BDNF gene (Val66Met (G196A) and C270T) and the Frontal Assessment Battery (FAB) score, which reflects executive function as a non-memory cognitive impairment.

METHODS

One hundred and sixty-nine outpatients with AD or amnestic mild cognitive impairment (A-MCI) were recruited to the study and divided into three genotypic groups for each representative BDNF functional polymorphism as follows: (i) Val66Met (G196A): G/G (n = 45), G/A (n = 104), and A/A (n = 20); and (ii) C270T: C/C (n = 160), C/T (n = 9), and T/T (n = 0). Then, age, sex ratio, duration of illness (months), education years, Mini-Mental State Examination (MMSE) score, behavioral pathology in Alzheimer disease (Behave-AD) score, Clinical Dementia Rating (CDR) ratio, and total and subtest FAB scores were compared between the genotypic groups for each SNP.

RESULTS

Significant differences were found in the total (P < 0.01) and subtest (conflicting instructions and prehension behavior; P < 0.01) FAB scores between the C270T polymorphism groups (C/C and C/T), but not among the G196A polymorphism groups. However, no significant differences in age, sex ratio, duration of illness (months), education years, Behave-AD score, CDR ratio, or MMSE score (reflecting attention and memory function) were found between the individual polymorphism genotypes (G196A and C270T).

CONCLUSION

Of the known BDNF polymorphisms, the C270T SNP may influence executive dysfunction as a non-memory cognitive impairment in Japanese patients with AD.

Association between executive dysfunction and hippocampal volume in Alzheimer's disease

BACKGROUND

Some previous research has hypothesized that executive dysfunction in patients with early Alzheimer's disease (AD) occurs as a result of a disconnection between different cerebral areas. The aim of the present study was to evaluate how the hippocampal volume influences executive function as a non-memory cognitive function.

METHODS

From 157 consecutive patients with AD or amnestic mild cognitive impairment (A-MCI), we recruited 107 subjects who had a global Clinical Dementia Rating (CDR) of 0.5 or 1.0 and whose degree of hippocampal atrophy had been measured using magnetic resonance imaging (MRI); the severity of atrophy was assessed using the voxel-based specific regional analysis for Alzheimer's disease (VSRAD) system. We divided the subjects into three groups: mild atrophy, 0 < Z-score < 1.0 (N = 21); moderate atrophy, 1.0 ≤ Z-score < 2.0 (N = 46); or severe atrophy, 2.0 ≤ Z-score < 4.0 (N = 40) according to the Z-score and compared the Frontal Assessment Battery (FAB) and its subtest scores between each atrophy group.

RESULTS

The results demonstrated that age, sex ratio, duration of illness, education years, MMSE score, Behave-AD score, and proportion of atrophy area in total brain (%) were not significantly different among the three groups. Only the go/no-go score among the six subtests was significantly lower for increasing atrophy severity (P < 0.05). Furthermore, hippocampal atrophy significantly influenced the go/no-go score independently of interactions from whether the diagnosis was early AD or A-MCI (P < 0.05).

CONCLUSION

These results support a significant association between hippocampal atrophy and executive dysfunction as a non-memory cognitive impairment in patients with early AD and A-MCI.

Regional cerebral blood flow and aberrant motor behaviour in Alzheimer's disease

Aberrant motor behaviour (AMB) in Alzheimer's disease shares behavioural correlates with obsessive compulsive disorder (OCD). We investigated whether AMB was also comparable in terms of metabolic activity in the orbitofrontal cortex (OFC), an area shown to be hyperactive in OCD. In this study 135 patients meeting research criteria for Alzheimer's disease were identified from a database of patients recruited as part of a phase II drug trial. These patients were assessed using the Neuropsychiatric Inventory, the Alzheimer's disease assessment scale, cognitive subscale and perfusion SPECT performed with 99Tc(m) hexamethylpropyleneamine oxime. Regions of interest were created for orbitofrontal cortices and basal ganglia. In 35 patients with AMB, adjusted tracer uptake was greater in the OFC. This reached statistical significance in right superior, left superior, right medial and left medial orbital gyri (p < 0.05). The association between AMB and hyperactivity in the OFC remained significant after adjusting for the presence of anxiety. These results parallel the OFC hypermetabolism consistently seen in OCD. One model of OCD, proposes that dysfunctional interactions between frontal regions, including the OFC, produce the characteristic symptoms of OCD. The behaviour is though to be brought about by a perceived incompleteness of performing a task and is caused by an error in normal reward signals initiated upon task completion. These finding indicate that AMB in Alzheimer's disease are brought about by the same mechanistic failure.