Frequency and clinical characteristics of early-onset dementia in consecutive patients in a memory clinic

Insights into young-onset dementia hospitalizations: An 8-year nationwide study using administrative data

OBJECTIVE

To characterize all Portuguese public hospitalizations of patients aged < 65 years with a primary or secondary diagnosis of dementia, based on ICD-9-CM coding.

METHODS

A retrospective observational study was conducted using a nationwide database encompassing all hospitalizations occurred in Portuguese mainland public hospitals with discharge from 2008 to 2015. Hospitalizations of patients aged 35-64 years with primary or secondary diagnoses of dementia were selected based on ICD-9-CM codes 290.1X-290.4X, 291.2, 292.82, 294.1X, 294.2X, 331.0, 331.1X, 331.82, 333.4 and 046.1, excluding diagnostic codes 317-319, 330.X, 343, 758.0-758.3 and 759.3. Information on age, sex, primary diagnosis, comorbidities (secondary diagnosis), type of admission, length of stay (LoS), in-hospital mortality, suicide attempts, discharge destination, readmissions and dementia etiology was collected.

RESULTS

From 7971 hospitalizations, for 5682 inpatients, the median age was 57.3 years (SD±6.5) and 61.8% were of male patients. Vascular dementia was the most prevalent etiology, followed by Alzheimer's disease. Most admissions were urgent and had a primary diagnosis of 'Delirium, dementia and other cognitive disorders', followed by pneumonia and alcohol-related disorders. Dementia, cerebrovascular disease and diabetes were the most common comorbidities. Overall, 55.4% of admissions were first-time admissions during the study period and the median LoS was 10.0 days (Q1;Q3: 5.0;20.0). Suicide attempts were recorded in 0.6% of the episodes. The in-hospital mortality rate was 9.2% and most patients were discharged home (80.2%).

CONCLUSIONS

This study describes the complexity and strain of young-onset dementia hospitalizations providing a detailed overview and recommendations for further research and tailored interventions.

Time to diagnosis in younger-onset dementia and the impact of a specialist diagnostic service

OBJECTIVES

While early diagnosis of younger-onset dementia (YOD) is crucial in terms of accessing appropriate services and future planning, diagnostic delays are common. This study aims to identify predictors of delay to diagnosis in a large sample of people with YOD and to investigate the impact of a specialist YOD service on this time to diagnosis.

DESIGN

A retrospective cross-sectional study.

SETTING

The inpatient unit of a tertiary neuropsychiatry service in metropolitan Victoria, Australia.

PARTICIPANTS

People diagnosed with a YOD.

MEASUREMENTS AND METHODS

We investigated the following predictors using general linear modeling: demographics including sex and location, age at onset, dementia type, cognition, psychiatric diagnosis, and number of services consulted with prior to diagnosis.

RESULTS

A total of 242 inpatients were included. The mean time to diagnosis was 3.4 years. Significant predictors of delay included younger age at onset, dementia type other than Alzheimer's disease (AD) and behavioral-variant frontotemporal dementia (bvFTD), and increased number of services consulted. These predictors individually led to an increased diagnostic delay of approximately 19 days, 5 months, and 6 months, respectively. A specialized YOD service reduced time to diagnosis by 12 months.

CONCLUSION

We found that younger age at onset, having a dementia which was not the most commonly occurring AD or bvFTD, and increasing number of services were significant predictors of diagnostic delay. A novel result was that a specialist YOD service may decrease diagnostic delay, highlighting the importance of such as service in reducing time to diagnosis as well as providing post-diagnostic support.

Incidence of Young Onset Dementia in Central Norway: A Population-Based Study

Background:

The epidemiology of young onset dementia is little researched compared to late onset dementia. Information on incidence rates is vital for medical professionals, and for government planning purposes.

Objective:

To determine the incidence of young onset dementia in a defined catchment area of central Norway.

Methods:

The target area was Trøndelag county in central Norway with a total population of 449,796 inhabitants per January 1, 2016. We applied multiple case ascertainment strategies with sources from both primary and secondary healthcare facilities. Included patients received a diagnosis of dementia according to DSM-IV in the ages 30 to 64 years during the years 2015–2017. Subtypes of dementia were diagnosed according to standardized criteria. Incidence rates for dementia and Alzheimer’s disease with dementia were calculated according to age and sex.

Results:

A total of 89 incident cases were included. Incidence rates for dementia were 14.8 and 25.0 per 100,000 person-years for the age range 30–64 and 45–64, respectively. Corresponding incidence rates for Alzheimer’s disease were 6.7 and 11.8. Alzheimer’s disease represented half of all dementias. A majority of patients above the age of 50 had neurodegenerative disease, whereas non-degenerative disorders were more prevalent in younger patients.

Conclusion:

Young onset dementia is a significant contributor to the overall occurrence of dementia in central Norway, and Alzheimer’s disease is by far the most common diagnosis.

A 10 year retrospective cohort study of inpatients with younger-onset dementia

OBJECTIVES

Younger-onset dementia (YOD) refers to a dementia where symptom onset occurs when the patient is less than 65 years of age. YOD is far less common than late-onset dementia (occurring when patients are over 65 years old) and more challenging to diagnose due to its heterogeneous presentation. There have been relatively few studies describing demographic and diagnostic characteristics of patients with YOD in the community, particularly with follow-up information.

METHODS

A retrospective cohort study was performed of inpatients admitted to a tertiary neuropsychiatry service, located in metropolitan Victoria, Australia, from 2009 to 2019. Inpatients with a YOD diagnosis were identified and data regarding diagnosis, demographics and investigations were obtained.

RESULTS

There were 849 individual inpatients who were admitted to the service in the 10-year period and received comprehensive assessment. There were 306 individuals who received a YOD diagnosis, using contemporaneous diagnostic criteria (frequency 36%). The most common diagnoses were Alzheimer's disease (24.2%), frontotemporal dementia (23.1%), Huntington's disease (16.7%) and vascular dementia (7.8%). More than half of these inpatients were followed up and 6.5% had a diagnostic change when reviewed.

CONCLUSIONS

This study reports on the largest cohort of YOD to date, with diagnostic breakdown similar to previous retrospective file reviews. The neuropsychiatry service is funded to follow-up its patients, thus allowing re-assessment and continuity of care. While there are limitations in this study such as the lack of neuropathological outcomes, the findings emphasise the strengths of follow-up and appropriate service provision for these patients.

The Prevalence and Subtypes of Young Onset Dementia in Central Norway: A Population-Based Study

Background:

Young onset dementia poses several challenges for the individual, health care, and society that are not normally relevant for late onset dementia, but is little researched.

Objective:

To determine the prevalence and subtypes of young onset dementia in a defined catchment area in central Norway.

Methods:

The main sources of patient identification were the databases at the Department of Neurology, University Hospital of Trondheim (St. Olav’s Hospital), and Department of Psychiatry, Levanger Hospital. Both departments are the main sites for referral of young onset dementia (onset before age 65 years) in the county, covering approximately 90% of the catchment area of the study. Other sources included key persons in the communities, collaborating hospital departments examining dementia, and review of hospital records of all three hospitals in the area. Included patients met the DSM-IV criteria for dementia. The prevalence of dementias was calculated by sex and age.

Results:

All patients identified with dementia and onset before 65 years on census date were included in the study (n = 390). Patients younger than 65 on census date were included in the calculation of prevalence, giving a result of 76.3 per 100 000 persons at risk in the age category of 30–65 years, and 163.1 per 100,000 for the category 45–64 years. Etiology was heterogeneous, but the main subtype of dementia was Alzheimer’s disease.

Conclusions:

Young onset dementia affects a significant number of people in central Norway. Prevalence figures are higher than previously reported from England and Japan, but are similar to a more recent study from Australia.

Memory Complaint Is a Surrogate for Memory Decline in the Middle-Aged: A Register-Based Study

Memory complaint is one of the earliest symptoms of dementia. The causes and prognosis of memory complaint in the middle-aged population remain largely unknown. We reviewed the register-based data of 2129 patients with memory complaints. Among them, 404 participants were between 40 and 65 years old. The participants were separated into three groups: subjective cognitive decline (SCD), neurodegenerative diseases (ND), and non-neurodegenerative diseases (NND). One-year decline was defined as a decrease of ≥1 on the mini-mental state examination (MMSE). At baseline, 131 participants (32%) were diagnosed with SCD, 141 (35%) with ND, and 132 (33%) with NND. The 1-year cognitive decline rate was higher among patients with ND (36.8%) than in the SCD (7.3%, p = 1.3 × 10⁻⁸) and NND groups (7.6%, p = 1.1 × 10⁻⁷). One-year decline did not differ between the SCD and NND groups. Lower baseline MMSE score predicted increased risk of 1-year cognitive decline (odds ratio (OR) = 1.126, 95% confidence interval (CI) = 1.076–1.178, p = 2.52 × 10⁻⁷). Memory complaint in middle age carried a risk of 1-year cognitive decline, and baseline MMSE is an independent predictor of decline. An initial diagnosis of SCD held the same risk effect for decline as NND. These findings highlighted the necessity for neuropsychological tests in those with memory complaints presenting to the clinic.

Disease Course Varies According to Age and Symptom Length in Alzheimer's Disease

Health-care professionals, patients, and families seek as much information as possible about prognosis for patients with Alzheimer's disease (AD); however, we do not yet have a robust understanding of how demographic factors predict prognosis. We evaluated associations between age at presentation, age of onset, and symptom length with cognitive decline as measured using the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating sum-of-boxes (CDR-SOB) in a large dataset of AD patients. Age at presentation was associated with post-presentation decline in MMSE (p < 0.001), with younger patients showing faster decline. There was little evidence of an association with change in CDR-SOB. Symptom length, rather than age, was the strongest predictor of MMSE and CDR-SOB at presentation, with increasing symptom length associated with worse outcomes. The evidence that younger AD patients have a more aggressive disease course implies that early diagnosis is essential.

Anosognosia and Its Relation to Psychiatric Symptoms in Early-Onset Alzheimer Disease

BACKGROUND

We investigated differences in the prevalence of anosognosia and neuropsychiatric symptoms (NPSs) characteristics according to disease severity in patients with early-onset Alzheimer disease (EOAD).

METHODS

We recruited 616 patients with EOAD. We subdivided participants into 2 groups based on the presence or absence of anosognosia and then again by Clinical Dementia Rating (CDR) scale. We compared the differences in the Neuropsychiatric Inventory (NPI) scores according to anosognosia and disease severity.

RESULTS

The percentage of patients with anosognosia in each CDR group steadily increased as the CDR rating increased (CDR 0.5 8.6% vs CDR 1 13.6% vs CDR 2 26.2%). The NPI total score was significantly higher in patients with anosognosia in the CDR 0.5 and 1 groups; by contrast, it had no association in the CDR 2 group. Frontal lobe functions were associated with anosognosia only in the CDR 0.5 and 1 groups. After stratification by CDR, in the CDR 0.5 group, the prevalence of agitation ( P = .040) and appetite ( P = .013) was significantly higher in patients with anosognosia. In the CDR 1 group, patients with anosognosia had a significantly higher prevalence of delusions ( P = .032), hallucinations ( P = .048), and sleep disturbances ( P = .047). In the CDR 2 group, we found no statistical difference in the frequency of symptoms between patients with and without anosognosia.

CONCLUSION

These results confirm that the prevalence of anosognosia as well as the individual NPS and cognitive functions associated with it differ according to EOAD severity.

Differences in Depressive Patterns According to Disease Severityin Early-Onset Alzheimer's Disease

BACKGROUND & OBJECTIVE

Depression frequently combines with dementia, including early-onset Alzheimer's disease (EOAD). We investigated differences in prevalence and characteristics of depressive symptoms according to dementia severity in EOAD patients.

METHODS

The 15-item Korean version of the Geriatric Depression Scale (GDS-15) was administered to 412 EOAD patients. Factor analysis was used to assess GDS-15 factor structure. We subdivided participants into three groups by disease severity, then compared the frequencies and scores of individual GDS-15 items and performed logistic regression analysis to assess associations between depressive symptoms and EOAD stage.

RESULTS

Factor analysis yielded three factor categories: 1) "hopelessness and ominousness" (symptoms no. 6, 8, 12, 14, 15); 2) "unhappiness and dissatisfaction" (no. 1, 3, 5, 7, 11); and 3) "monotony and lack of energy" (no. 2, 4, 9, 10, 13). Factor 2 depressive symptoms (no. 1, 5, 11) were less common in moderate EOAD. The risk of Factor 1 symptoms: no. 12 (OR, 2.04; 95% CI, 1.19-3.50; p = 0.010) and 14 (OR, 1.84; 95% CI, 1.07-3.16; p = 0.028) was higher in mild than very mild EOAD. The risk of Factor 2 symptoms: no. 9 (OR, 2.69; 95% CI, 1.08-6.71; p = 0.033) and 13 (OR, 2.12; 95% CI, 1.02-4.40; p = 0.043) was higher in moderate than mild EOAD.

CONCLUSION

We confirmed that depressive symptoms differ according to EOAD severity. When assessing depressive symptoms related to dementia progression, we recommend focusing on "hopelessness and ominousness" in very mild EOAD and "unhappiness and dissatisfaction" in mild EOAD.

Predictive factors for disease progression in patients with early-onset Alzheimer's disease

BACKGROUND

Only a few studies have investigated disease progression in patients with early-onset Alzheimer's disease (EOAD). Therefore, the aim of this study was to investigate disease progression in patients with EOAD and the influence of various factors, such as gender, education, and apolipoprotein E (APOE) genotype on disease progression.

METHODS

A total of 288 EOAD patients were enrolled in the study. Linear mixed models were used to investigate the rate of cognitive and functional decline in terms of age at onset, gender, education, follow-up period, and APOE genotype.

RESULTS

EOAD patients showed an annual decline of -1.54 points/years in the Korean version mini-mental examination score, an annual increase of 3.46 points/year in the Seoul instrumental activities of daily living (SIADL) score, and an annual increase of 1.15 points/year in the clinical dementia rating scale-sum of boxes score. After stratification, higher educated patients showed faster disease progression in all three parameters, and female patients demonstrated faster disease progression as assessed by the SIADL score. Age at onset and APOE genotype had no influence on disease progression.

CONCLUSION

We confirmed the rate of disease progression in Korean patients with EOAD in real-life hospital-based clinical practice. The results of this study suggest that education and female gender, not APOE genotype, may be important as independent strong predictive factors for disease progression in patients with EOAD.

Glucose Metabolic Brain Networks in Early-Onset vs. Late-Onset Alzheimer's Disease

Objective: Early-onset Alzheimer's disease (EAD) shows distinct features from late-onset Alzheimer's disease (LAD). To explore the characteristics of EAD, clinical, neuropsychological, and functional imaging studies have been conducted. However, differences between EAD and LAD are not clear, especially in terms of brain connectivity and networks. In this study, we investigated the differences in metabolic connectivity between EAD and LAD by adopting graph theory measures.

Methods: We analyzed ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) images to investigate the distinct features of metabolic connectivity between EAD and LAD. Using metabolic connectivity and graph theory analysis, metabolic network differences between LAD and EAD were explored.

Results: Results showed the decreased connectivity centered in the cingulate gyri and occipital regions in EAD, whereas decreased connectivity in the occipital and temporal regions as well as increased connectivity in the supplementary motor area were observed in LAD when compared with age-matched control groups. Global efficiency and clustering coefficients were decreased in EAD but not in LAD. EAD showed progressive network deterioration as a function of disease severity and clinical dementia rating (CDR) scores, mainly in terms of connectivity between the cingulate gyri and occipital regions. Global efficiency and clustering coefficients were also decreased along with disease severity.

Conclusion: These results indicate that EAD and LAD have distinguished features in terms of metabolic connectivity, with EAD demonstrating more extensive and progressive deterioration.

Prognosis of Early-Onset vs. Late-Onset Mild Cognitive Impairment: Comparison of Conversion Rates and Its Predictors

BACKGROUND

Despite having the same histopathological characteristics, early-onset and late-onset Alzheimer's disease (AD) patients show some distinct clinical and neuropsychological profiles. Early Onset Mild Cognitive Impairment (EOMCI) is a less characterized group. The aim of this study is to characterize MCI probably due to AD in terms of the clinical, genetic, Cerebrospinal fluid (CSF) biomarkers profile and conversion rate of EOMCI, compared to the late-onset form (LOMCI).

METHODS

159 MCI patients were divided in two groups: 52 EOMCI (onset < 65 years) and 107 LOMCI (onset ≥ 65 years). We investigated differences in neuropsychological scores, clinical variables, ApoE genotype, CSF biomarkers (Aβ42, t-Tau and p-Tau) in both groups. Conversion was ascertained during follow-up.

RESULTS

EOMCI showed a longer duration of symptoms prior to the first evaluation (EOMCI = 4.57 vs. LOMCI = 3.31, p = 0.008) and scored higher on the subjective memory complaints scale (9.91 vs. 7.85, p = 0.008), but performed better in brief cognitive tests (27.81 vs. 26.51, p < 0.001 in Mini-Mental State Examination; 19.84 vs. 18.67, p = 0.005 in Montreal Cognitive Assessment) than LOMCI. ApoE genotype distribution and CSF biomarker profile were similar in both groups, as was the conversion risk. Lower Aβ42 (Hazard ratio (HR): 0.998, 95% Confidence Interval (CI) = [0.996⁻1.000], p = 0.042), higher t-Tau levels (HR: 1.003, 95%CI = [1.000⁻1.005], p = 0.039) and higher scores in the Alzheimer Disease Assessment Scale-Cognitive (HR: 1.186, 95%CI = [1.083⁻1.299], p = 0.002) increased the risk of conversion.

DISCUSSION

Despite differences in memory performance and memory complaints, EOMCI and LOMCI seem to represent indistinct biological groups that do not have a higher risk of conversion to AD or differ in risk factors for conversion.

When a Little Knowledge Can Be Dangerous: False-Positive Diagnosis of Behavioral Variant Frontotemporal Dementia among Community Clinicians

BACKGROUND

Accurate diagnosis of behavioral variant frontotemporal dementia (bvFTD) is important as patients' behavioral symptoms have profound implications for their families and communities. Since the diagnosis of bvFTD derives from behavioral features, accurate identification of patients can be difficult for non-specialists. Concrete rates of diagnostic accuracy among non-specialists are unavailable.

METHODS

To examine the accuracy of community clinicians' diagnoses of bvFTD and to identify patient characteristics leading to misdiagnosis, we reviewed the charts and referral letters of 3,578 patients who were seen at our specialized center. Referral diagnosis and reasons, manifesting symptoms, demographic data, Mini-Mental State Examination score, Clinical Dementia Rating score and Neuropsychiatric Inventory score were extracted.

RESULTS

60% of patients assigned a single diagnosis of bvFTD by community clinicians did not have bvFTD according to specialists. Compared to specialist-confirmed bvFTD patients, false bvFTD patients were more likely to be depressed and to be non-Caucasian, showed less euphoria, apathy, disinhibition and abnormal eating behaviors, had milder disease severity and better overall cognition. bvFTD was mentioned by referring clinicians in 86% of specialist-confirmed bvFTD cases, but missed cases were called Alzheimer's, Parkinson's or Huntington's disease, or progressive aphasia.

CONCLUSION

These results revealed a widespread lack of familiarity with core diagnostic symptoms among non-specialists and suggest that community clinicians require specialized diagnostic support before providing a definitive diagnosis of bvFTD.

Young-onset dementia epidemiology applied to neuropsychiatry practice

A substantial number of adults suffer young-onset dementia (YOD). The diversity of types and syndromes makes recognition and diagnosis difficult. An algorithmic approach to interpreting clinical data, informed by clinical epidemiology, integrates data pertaining to defining syndromes and their chronology and tempo, family history, and other neuropsychiatric features and neurologic signs, is used to reach a preliminary diagnosis and direct diagnostic tests and their interpretation. Screening for YOD in the psychiatric context is a rational process in which vigilance is combined with careful searches for red flags that signal a neurodegenerative etiology.

The neuropsychiatric examination of the young-onset dementias

Young-onset dementias frequently present with prominent behavioral features and constitute a diagnostic challenge. Most cases are secondary to neurodegenerative conditions, including the behavioral variant of frontotemporal dementia, which has overlapping symptoms with many primary psychiatric disorders. This article reviews the differential diagnosis and neuropsychiatric assessment of young-onset dementia, which includes detailed history taking, family history, mental status examination, office-based cognitive tests, and a focused neurologic examination. The clinical examination serves to establish the presence of a dementia and the specific clinical syndrome. Biomarkers can be subsequently integrated in a probabilistic model to determine the most likely neuropathological process.

Alzheimer's disease first symptoms are age dependent: Evidence from the NACC dataset

INTRODUCTION

Determining the relationship between age and Alzheimer's disease (AD) presentation is important to improve understanding and provide better patient services.

METHODS

We used AD patient data (N = 7815) from the National Alzheimer Coordinating Center database and multinomial logistic regression to investigate presentation age and first cognitive/behavioral symptoms.

RESULTS

The odds of having a nonmemory first cognitive symptom (including impairment in judgment and problem solving, language, and visuospatial function) increased with younger age (P < .001, all tests). Compared with apathy/withdrawal, the odds of having depression and "other" behavioral symptoms increased with younger age (P < .02, both tests), whereas the odds of having psychosis and no behavioral symptom increased with older age (P < .001, both tests).

DISCUSSION

There is considerable heterogeneity in the first cognitive/behavioral symptoms experienced by AD patients. Proportions of these symptoms change with age with patients experiencing increasing nonmemory cognitive symptoms and more behavioral symptoms at younger ages.

Early onset degenerative dementias: demographic characteristics and etiologic classification in a tertiary referral center

Early onset dementia (EOD) is a major diagnostic challenge as it often presents with atypical features and may be attributed to treatable diseases. Primary degenerative dementias (Alzheimer's disease-AD, frontotemporal lobar degeneration-FTLD, Lewy body dementia-LBD), although traditionally considered to affect older people, are still a main cause of EOD. 491 demented patients were assessed from January 1, 2003 to December 31, 2010 in the Neurology Department of a tertiary referral center. Patients were classified as AD, behavioral variant frontotemporal dementia (bvFTD), non-fluent agrammatic variant primary progressive aphasia (naPPA), semantic variant PPA (svPPA), corticobasal degeneration (CBD), or progressive supranuclear palsy (PSP) who also met criteria for naPPA and LBD. Finally, their demographic characteristics were analysed, according to age at onset (EOD <65 years, late onset dementia-LOD ≥65 years). From the 491 patients, 137 (27.9 %) were EOD. In the EOD group, 52 (38 %) were diagnosed with bvFTD, 34 (24.8 %) with AD, 27 (19.7 %) with naPPA, 10 (7.2 %) with svPPA, 12 (8.8 %) with CBD or PSP, and 2 (1.5 %) with LBD. Demographic characteristics did not differ significantly among diagnostic categories in the EOD group, while in the LOD group FTLD patients were younger and more frequently men compared to both AD and LBD patients. EOD patients had more years of education than LOD patients. Degenerative disorders as causes of EOD are not rare. High clinical alertness is warranted to achieve correct and timely diagnosis.

Multicenter population-based study on the prevalence of early onset dementia in Japan: vascular dementia as its prominent cause

AIM

In Japan, the government and media have become aware of the issues of early onset dementia (EOD), but policies for EOD have not yet been established and support systems are inadequate. To provide practical data about EOD, a two-step postal survey was performed.

METHODS

A questionnaire requesting information on EOD cases was sent to target institutions in five catchment areas in Japan. According to the answers from the institutions, we estimated the prevalence of EOD using census data and determined the illnesses causing EOD. As a quality control study, the authors reviewed every diagnosis in a quarter of the reported cases using the medical and psychiatric records and neuroimaging data. This study was conducted from 2006 to 2007.

RESULTS

Information from 2469 patients was collected from 12,747 institutions, and 2059 subjects with EOD were identified. The estimated prevalence of EOD was 47.6 per 100,000 (95% confidence interval, 47.1-48.1) for all of Japan. Of the illnesses causing EOD, vascular dementia (VaD) was the most frequent (39.8%), followed by Alzheimer's disease.

CONCLUSIONS

The prevalence of EOD in Japan appeared to be similar to that in Western countries. However, unlike previously reported international experience, VaD was the most frequent cause of EOD in all catchment areas in Japan.

The prevalence and incidence of dementia with Lewy bodies: a systematic review of population and clinical studies

BACKGROUND

Dementia with Lewy bodies (DLB) is increasingly recognized as a common cause of dementia in older people. However, its true frequency remains unclear, with previous studies reporting a prevalence range from zero to 22.8% of all dementia cases. This review aimed to establish the population prevalence and incidence for DLB and to compare this to its prevalence in secondary care settings.

METHOD

A literature review of all relevant population and clinical studies was conducted using PubMed. Additional references from papers found during that process were added to this.

RESULTS

DLB accounted for 4.2% of all diagnosed dementias in the community. In secondary care this increased to 7.5%. The incidence of DLB was 3.8% of new dementia cases. There was a significant increase in DLB diagnoses when using the revised (2005) International Consensus Criteria (ICC) for DLB compared to the original (1996) criteria.

CONCLUSIONS

DLB currently accounts for around one in 25 dementia cases diagnosed in the community and one in 13 cases in secondary care. The significantly higher rates of DLB in secondary care may reflect enhanced diagnostic accuracy in specialist settings and/or the increased morbidity and carer burden of the DLB syndrome compared to other dementias. However, the true prevalence is likely to be much higher because DLB diagnoses are often missed, although there is evidence that new criteria aid case identification.

Inadequate diagnostic evaluation in young patients registered with a diagnosis of dementia: a nationwide register-based study

BACKGROUND

Establishing a diagnosis of dementia in young patients may be complex and have significant implications for the patient. The aim of this study was to evaluate the quality of the diagnostic work-up in young patients diagnosed with dementia in the clinical routine.

METHODS

Two hundred patients were randomly selected from 891 patients aged ≤65 years registered with a diagnosis of dementia for the first time in 2008 in Danish hospitals, and 159 medical records were available for review. Three raters evaluated their medical records for the completeness of the diagnostic work-up on which the diagnosis of dementia had been based, using evidence-based guidelines for the diagnostic evaluation of dementia as reference standards.

RESULTS

According to the rater review, only 111 (70%) patients met the clinical criteria for dementia. An acceptable diagnostic work-up including all items of recommended basic diagnostic evaluation was performed in only 24%, although more often (28%) in the subgroup of patients where dementia was confirmed by raters.

CONCLUSION

This first nationwide study of unselected young patients registered with a diagnosis of dementia indicated that the concept of dementia may be misinterpreted by clinicians and that a diagnosis of dementia in the young is only rarely based on a complete basic diagnostic work-up, calling for increased competency.

Epidemiology of early-onset dementia: a review of the literature

Presenile Dementia or Early Onset Dementia (EOD) is a public health problem, it differs from Senile Dementia, and encloses a significant number of cases; nevertheless, it is still poorly understood and underdiagnosed. This study aims to review the prevalence and etiology of EOD, comparing EOD with Senile Dementia, as well as to show the main causes of EOD and their prevalence in population and non-population based studies. The computer-supported search used the following databases: Pubmed/Medline, ISI Web of Knowledge and Scielo. The search terms were alcohol-associated dementia, Alzheimer's disease, dementia, Creutzfeldt-jakob disease, dementia with lewy bodies, early onset dementia, frontotemporal lobar degeneration, Huntington's disease, mixed dementia, neurodegenerative disorders, Parkinson's disease dementia, presenile dementia, traumatic brain injury, vascular dementia. Only papers published in English and conducted from 1985 up to 2012 were preferentially reviewed. Neurodegenerative diseases are the most common etiologies seen in EOD. Among the general population, the prevalence of EOD was found to range between 0 to 700 per 100.000 habitants in groups of 25-64 years old, with an increasing incidence with age. The progression of EOD was found to range between 8.3 to 22.8 new cases per 100.000 in those aged under 65 years. Alzheimer's disease (AD) is the major etiology, followed by Vascular Dementia (VaD) and Frontotemporal Lobar Degeneration (FTLD). A larger number of epidemiological studies to elucidate how environmental issues contribute to EOD are necessary, thus, we can collaborate in the planning and prevention of services toward dementia patients.

Exacerbated CSF abnormalities in younger patients with Alzheimer's disease

Increasing age is the most important risk factor for developing Alzheimer's disease (AD). The aim of this study was to investigate the relationships between age and cerebrospinal fluid (CSF) levels of β-amyloid (Aβ 1-42), total Tau and phosphorylated Tau (pTau-181), in AD and non-AD patients explored for cognitive disorders. 966 patients (AD, n=528; non-AD, n=438) were included between January 2008 and December 2010 (mean age, 69.5years; mean MMSE, 20.2) from three French memory centers. Multivariable linear regression models were used to study the relationship between CSF biomarker levels and age in AD and non-AD patients. The capacity of each CSF biomarker in discriminating patients was evaluated using the area under the receiver-operating characteristic (ROC) curves by quartile of distribution of age. In AD patients, older age was associated with higher CSF Aβ 1-42 and lower Tau levels. Conversely, in non-AD patients, age was associated with lower CSF Aβ 1-42, higher Tau, and higher pTau-181 levels. In sex-stratified analysis, these relationships were significant only in women. Using ROC curve analysis, CSF AD biomarkers were more discriminant in younger patients than in older ones. In this clinically-based study, younger patients with AD had exacerbated CSF anomalies compared to older patients with AD. CSF biomarkers were more discriminant in younger patients than in older ones for the diagnosis of AD, especially in women. These results support the idea of an overlap in AD neuropathological lesions in oldest subjects with or without AD.

A longitudinal study of physical function in patients with early-onset dementia

Background

The aim of this study was to explore changes in mobility in terms of ambulation and transfer over 1 year in patients with early-onset Alzheimer's disease (EOAD), and to compare mobility in EOAD with patients with other types of early-onset dementia (EOOD).

Method

Forty-two patients with EOAD and 30 patients with EOOD were included. All patients were home-dwelling and had mild or moderate degree of dementia. Mobility was assessed using the Timed Up and Go Test (TUG), a modified version of the Clinical Outcome Variables Scale, timed stair walking, and timed rise from the floor.

Results

The EOAD group performed significantly better than the EOOD group on all mobility tests. After 1 year, 25 persons with EOAD were tested again. The performance on TUG (p = 0.028) and stair walking (p = 0.02) had deteriorated at the 1-year follow-up in the EOAD group.

Conclusion

Patients with EOAD performed better on mobility tasks than patients with EOOD, but their performance deteriorated at 1-year follow-up.

Nonamnestic presentations of early-onset Alzheimer's disease

Early-onset Alzheimer's disease (EOAD) beginning before the age of 65 may differ from late-onset AD (LOAD) in clinical course and frequency of nonamnestic presentations. In a 10-year retrospective review, 125 patients with EOAD, diagnosed clinically and verified by functional neuroimaging, were compared with 56 patients with LOAD and further classified depending on predominant cognitive difficulty on presentation. Eighty (64%) of the patients with EOAD had a nonamnestic presentation, compared with only 7 (12.5%) of the patients with LOAD. Compared with LOAD, the patients with EOAD had a shorter duration with lower Mini-Mental State Examination scores. The neuroimaging reports among the patients with EOAD showed more hippocampal atrophy with an amnestic presentation, more left parietal changes with impaired language presentations, and more right parietal and occipital changes with impaired visuospatial presentations. These findings indicate that EOAD differs from LOAD in a more aggressive course and in having predominantly nonamnestic presentations that vary in neuropathological location.

Study protocol: EXERcise and cognition in sedentary adults with early-ONset dementia (EXERCISE-ON)

Background

Although the development of early-onset dementia is a radical and invalidating experience for both patient and family there are hardly any non-pharmacological studies that focus on this group of patients. One type of a non-pharmacological intervention that appears to have a beneficial effect on cognition in older persons without dementia and older persons at risk for dementia is exercise. In view of their younger age early-onset dementia patients may be well able to participate in an exercise program. The main aim of the EXERCISE-ON study is to assess whether exercise slows down the progressive course of the symptoms of dementia.

Methods/Design

One hundred and fifty patients with early-onset dementia are recruited. After completion of the baseline measurements, participants living within a 50 kilometre radius to one of the rehabilitation centres are randomly assigned to either an aerobic exercise program in a rehabilitation centre or a flexibility and relaxation program in a rehabilitation centre. Both programs are applied three times a week during 3 months. Participants living outside the 50 kilometre radius are included in a feasibility study where participants join in a daily physical activity program set at home making use of pedometers. Measurements take place at baseline (entry of the study), after three months (end of the exercise program) and after six months (follow-up). Primary outcomes are cognitive functioning; psychomotor speed and executive functioning; (instrumental) activities of daily living, and quality of life. Secondary outcomes include physical, neuropsychological, and rest-activity rhythm measures.

Discussion

The EXERCISE-ON study is the first study to offer exercise programs to patients with early-onset dementia. We expect this study to supply evidence regarding the effects of exercise on the symptoms of early-onset dementia, influencing quality of life.

Trial registration

The present study is registered within The Netherlands National Trial Register (ref: NTR2124)

Differences between Early and Late-Onset Alzheimer's Disease in Neuropsychological Tests

Although patients with Alzheimer disease (AD) share clinical and histological features regardless of age of onset, the hypothesis that early onset AD constitutes a distinct subgroup prevails. Some authors suggest that early attention or language impairment constitute patterns of differentiation in terms of neuropsychological profile, between these groups. However, investigations are not consensual in terms of cognitive domains affected in each group. Aim: To investigate whether there is early neuropsychological difference between two types of AD using the conventional dividing line of 65 years. Methods: We evaluated the results obtained in the Mini-Mental State Examination (MMSE) and in a comprehensive neuropsychological battery – Battery of Lisbon for the Assessment of Dementia (BLAD), at a Dementia clinic in the University Hospital of Coimbra and a Memory Clinic. The study was developed in consecutive patients with a clinical probable diagnosis of mild to moderate AD, using standard criteria (DSMIV and NINCDS-ADRDA). Statistical analysis was performed using Qui-square and U-Mann–Whitney, for categorical and non-categorical variables. The degree of relation between variables, was measured using the coefficient of correlation r_s de Spearman. Results: The total sample included 280 patients: 109 with early onset AD and 171 with a late-onset form. Groups were comparable in terms of gender, education or severity of disease, and MMSE. In BLAD, for univariate analysis the early onset group had lower scores in Naming (p = 0.025), Right–Left Orientation (p = 0.029) and Praxis (p = 0.001), and better performances in Orientation (p = 0.001) and Visual Memory (p = 0.022). After application of Bonferroni correction for multiple comparisons only Praxis and Orientation could differentiate the two groups. No significant differences were found in other tests or functions. Discussion: The results are suggestive of dissociated profiles between early and late-onset AD. Younger patients have a major impairment in Praxis and a tendency for a great impairment in neocortical temporal functions. AD patients with late-onset forms had a tendency for worse performances in Visual Memory and Orientation, suggesting a more localized disease to the limbic structures.

Exercise and early-onset Alzheimer's disease: theoretical considerations

BACKGROUND/AIMS

Although studies show a negative relationship between physical activity and the risk for cognitive impairment and late-onset Alzheimer's disease, studies concerning early-onset Alzheimer's disease (EOAD) are lacking. This review aims to justify the value of exercise interventions in EOAD by providing theoretical considerations that include neurobiological processes.

METHODS

A literature search on key words related to early-onset dementia, exercise, imaging, neurobiological mechanisms, and cognitive reserve was performed.

RESULTS/CONCLUSION

Brain regions and neurobiological processes contributing to the positive effects of exercise are affected in EOAD and, thus, provide theoretical support for exercise interventions in EOAD. Finally, we present the design of a randomized controlled trial currently being conducted in early-onset dementia patients.

Epidemiological survey of frontotemporal lobar degeneration in tottori prefecture, Japan

BACKGROUND

The prevalence of frontotemporal lobar degeneration (FTLD) in Japan is unknown. An epidemiological survey study of FTLD was undertaken in Tottori Prefecture, a district in the western region of Japan.

METHODS

Hospitals in Tottori Prefecture were surveyed by a two-step questionnaire in 2010, and the prevalence of FTLD per 100,000 inhabitants was calculated using the actual number of patients and inhabitants in Tottori Prefecture on the prevalence day of October 1, 2010.

RESULTS

In this survey, 66 patients were diagnosed with FTLD. The subtypes of FTLD were as follows: 62 cases of frontotemporal dementia (FTD), 3 cases of progressive nonfluent aphasia, and 1 case of semantic dementia. Among the FTD cases, 5 cases were FTD with motor neuron disease and 1 case was FTD with parkinsonism linked to chromosome 17. The prevalence of FTD in the total population of Tottori Prefecture was 11.2 per 100,000 inhabitants. Based on these results, the prevalence of FTLD in Japan in 2008 was estimated to be 9.5 per 100,000 individuals.

CONCLUSIONS

Our epidemiological survey results suggest that there are at least 12,000 FTLD patients in Japan, indicating that FTLD is not a rare disease.

[Diagnostic profile of young-onset dementia before 65 years. Experience of a French Memory Referral Center]

OBJECTIVE

The aim of the study was to compare the profiles of patients with young (age≤65 years) and late (age>65 years) onset of dementia in a memory clinic of a Memory Referral Center in Lyons (France), for the year 2008.

METHODS

A total of 746 demented patients were evaluated using clinical, neuropsychological and imaging information. For each patient, diagnoses of the dementing disorder used clinical criteria at the first visit. We examined the distribution of patients diagnosis and differences in sex and education between the young-onset dementia (YOD) and the late-onset dementia (LOD) groups.

RESULTS

From a total of 746 registered demented patients (300 men, 446 women), there were 91 patients (12.2%) with YOD (from 36.5 to 65 years) and 655 patients with LOD (from 66 to 92 years). Among the 91 YOD patients, the most frequent causes were Mild Cognitive Impairment (MCI) (18.7%), then Alzheimer's disease (AD), frontotemporal dementia and posterior cortical atrophy (14.3% each), followed by progressive aphasia (11.0%), dementia with Lewy bodies (DLD) (9.9%), semantic dementia (8.8%), other causes (3.3%), vascular dementia (2.2%), undetermined dementia (2.2%), AD+cerebrovascular disease (1.1%). Among the 655 LOD patients, AD was the most frequent cause of dementia (57.4%). Referred cases by a specialist doctor were 50.5% in the YOD group and 12.7% in the LOD group (P<0.0001). In the ACP group, 68.4% patients began before 65 years.

CONCLUSION

The number of YOD in our memory clinic was four-fold the number of expected patients in France. The characteristics of the Referral Center explain the high frequency of rare dementia such as progressive aphasia (5.2% of overall number), semantic dementia (3.6%) and posterior cortical atrophy (2.5%).

Exploring the role of cognitive reserve in early-onset dementia

AIM

Cognitive reserve (CR) is important in protecting the brain from injury and has not been investigated in people with early-onset dementia (EOD).

METHODS

A retrospective case control study of 44 patients with dementia onset prior to 65 years of age: Alzheimer's disease (AD) = 23; frontotemporal dementia (FTD) = 21. Groups were matched for age, education, Mini-Mental State Examination (MMSE), premorbid IQ, sex and APOE ε4 genotype. Years of formal education were used as a marker of CR. Relationships between education and neuropsychological data was examined using linear regression analyses.

RESULTS

There were no demographic differences between the AD and FTD groups. Significant associations were found between education and attention, working memory and visuospatial abilities. There was an effect of CR for the EOD group and selective effects in FTD and AD.

CONCLUSION

Our findings suggest CR is operational in patients with FTD and AD.

Needs in early onset dementia: A qualitative case from the NeedYD study

OBJECTIVES

The aim was to explore the experiences of a caregiver of a patient with early onset dementia (EOD) and the needs of patient and caregiver.

METHODS

A single case study design was used to explore (1) unmet needs of patient and caregiver and (2) caregiver's experiences of transitions in care and health care services. A qualitative analysis was used to examine the data.

RESULTS

This study shows that a patient with EOD and the caregiver were confronted with specific issues during the care process, namely (1) prolonged time to diagnosis, (2) a lack of fit between needs and services, (3) the strain of dedication to care versus the caregiver's own future perspective, (4) the need for response of health care services to changing individual preferences.

CONCLUSION

This study illustrates specific issues related to early onset dementia that require specialized EOD care such as the differential and changing needs of patients and caregivers.

Frequency and causes of early-onset dementia in a tertiary referral center in Athens

OBJECTIVE

To investigate the frequency and causes of early-onset dementia (EOD) in consecutive patients in a highly specialized dementia referral center, focusing on unusual cases, particularly with early and/or rapid onset, in Athens, Greece.

METHODS

Patients referred for dementia diagnosis according to specific referral criteria during a 3 years period. We examined the distribution of patients diagnosis and differences in sex, education, dementia severity, cognitive function, and the duration of disease (from onset to referral) between the EOD (<65 y) and the late-onset dementia (LOD) groups.

RESULTS

From a total of 260 consecutive demented patients, there were 114 EOD patients or 44% of all demented patients. No significant differences were observed between the EOD and LOD groups in cognitive or behavioral measures. However, the duration from onset to consultation was significantly longer in the EOD group. Also, in the EOD group, the rates of patients with Alzheimer disease and Parkinson disease dementia were relatively low and the rate of patients with frontotemporal lobar degeneration was relatively high and the proportion of secondary dementias was high.

CONCLUSIONS

We conclude that EOD patients are more likely to be seen in specialized settings. The underlying diseases are considerably different in EOD compared with LOD. Secondary causes are often found in patients with EOD. Patients with EOD had an unexpectedly longer time-to-diagnosis than patients with LOD. This argues for a need of better education about the clinical presentation of dementia in the young and middle aged.

Early onset dementia: clinical and social aspects

BACKGROUND

Increasing efforts are being devoted to the study of early onset dementia (EOD), namely dementia in persons under the age of 65. Until recently, it was assumed that dementia occurs primarily among people aged 65 and over. However, since the number of persons with EOD is increasing, its importance as a clinical and social problem is rising accordingly. The aim of the present paper is to summarize research in this area.

METHODS

We reviewed the research published to date on EOD, and divided the current body of knowledge into several main sections.

RESULTS

The first section focuses on clinical aspects and summarizes findings regarding prevalence, causes, symptoms, diagnosis, and management of persons with EOD. The second section focuses on social aspects related to the cost of care for young people with the disease, the challenges faced by individuals and caregivers, and the services available for this population. Finally, conclusions and future directions are suggested.

CONCLUSIONS

Research on EOD is still in its early stages. There is an urgent need to expand research that will lead to more effective diagnosis and management of EOD as well as to the allocation of funds and the development of appropriate services suitable for the unique needs of young people with dementia.

Cognitive and noncognitive neurological features of young-onset dementia

BACKGROUND

The rarity of young-onset dementia (YOD), the broad differential diagnosis and unusual clinical presentations present unique challenges to correctly recognize the condition and establish an accurate diagnosis. Limited data exist regarding clinical features associated with dementia prior to the age of 45.

METHODS

We retrospectively assessed cognitive and noncognitive neurological characteristics of 235 patients who presented for evaluation of YOD to investigate the clinical characteristics of YOD compared to later-onset dementias and to identify clinical features associated with specific etiologies that may aid in the evaluation of YOD.

RESULTS

Multiple cognitive domains were affected in most patients, and no significant differences in affected domains existed between groups. Early psychiatric and behavioral features occurred at very high frequencies. Nearly 80% of this YOD cohort had additional noncognitive symptoms or signs as a feature of their disease. Chorea was strongly associated with Huntington disease. Parkinsonism was not seen in patients having an autoimmune/inflammatory etiology.

CONCLUSIONS

The rarity of YOD and the high frequency of early psychiatric features led to frequent misdiagnosis early in the clinical course. The high frequency of noncognitive symptoms and signs may aid clinicians in distinguishing patients requiring a more extensive evaluation for YOD.

[Frequency and clinical characteristics of individuals with presenile dementia in Aichi prefecture]

The aim of this study is to investigate the frequency, causes, and clinical characteristics of individuals with presenile dementia with an age of onset less than 65 years. A staged questionnaire survey was performed among all hospitals and clinics, all faculties of care and welfare services, and all local governmental offices in Aichi prefecture. The response rate of the primary survey was 62.3%, and that of the secondary survey was 90.1%. The number of people with presenile dementia after adjusting for duplicated subjects was 1,092 (569 men, 520 women and 3 of unknown gender). The average age was 60.7 +/- 7.1 (mean +/- SD) years, and age of onset was 55.1 +/- 7.8 years. Vascular dementia (VD) was the most frequent cause in men (42.2%), followed by Alzheimer's disease (AD: 24.8%), frontotemporal dementia (FTD: 4.6%) and Parkinson disease (PD: 3.8%). In women, AD was the most common (45.8%), followed by VD (25.4%), FTD (7.4%) and PD (3.4%). Overall, AD and VD were the most common causes of presenile dementia, followed by FTD and PD. The highest prevalence of presenile dementia was seen in the age range of 60- 64-years-old. This was true for both men and women.

What is 'early onset dementia'?

There are two types of dementia with early onset: (i) presenile dementias; and (ii) senile dementias with early onset. Most patients who develop dementia before 65 years of age have Alzheimer's disease (AD). The remainder are likely to have vascular dementia (VaD), frontotemporal dementia, head injury, alcohol intoxication, or metabolic disorder. Presenile dementias, caused by frontotemporal lobar degeneration, progressive supranuclear palsy, and corticobasal degeneration, usually occur in patients of presenile and are rarely seen in patients of senile age. Although the factors responsible for the accelerated onset of the illness are not fully known, genetic abnormalities appear to be important in some types of presenile dementia, such as frontotemporal dementia with parkinsonism linked to chromosome 17. Conversely, senile dementias such as sporadic AD and VaD commonly occur in patients of senile age. These disorders may also occur in patients of presenile age, although less frequently. Alzheimer's disease was originally classified as a 'presenile dementia'. Since the 1980s, 'senile dementia of Alzheimer type' (SDAT) and 'Alzheimer's disease' have been considered to belong to the same pathological entity and both are now known as 'dementia of Alzheimer's type (DAT)' or merely 'Alzheimer's disease'. Rapid progression of cognitive impairment with neuropsychological syndromes and neurological symptoms has been considered a characteristic of early onset AD. However, recently, neurological symptoms such as spastic paraparesis, seizures, and myoclonic convulsions have been reported to occur infrequently in early onset AD, although language problems and visuospatial dysfunctions are common. There are at least three dominant genes that have been identified in cases of familial Alzheimer's disease with early onset, namely the amyloid precursor gene (APP), and the genes encoding presenilin 1 (PSEN1) and presenilin 2 (PSEN2). Therefore, genetic abnormalities are important factors contributing to the earlier onset of the illness. It is also important to investigate the pathophysiological mechanism in relation to genetic abnormalities, environmental factors, physical illnesses, and metabolic disturbances to understand the processes underlying the development of dementia with early onset.

Frontal-executive versus posterior-perceptual mental status deficits in early-onset dementias

BACKGROUND

Compared to late-onset dementias, early-onset dementias (EODs) may have greater focal cognitive involvement with differences in frontal-executive compared to posterior-perceptual deficits.

OBJECTIVE

This study evaluated whether mental status screening based on this frontal-posterior axis can distinguish EODs.

METHODS

Twenty-three patients each with early-onset Alzheimer's disease (eAD), frontotemporal dementia (FTD), or subcortical ischemic vascular disease (SIVD), and 20 normal controls underwent the Frontal Assessment Battery (FAB) and the Perceptual Assessment Battery (PAB).

RESULTS

Compared to controls, SIVD and FTD groups were impaired on the FAB whereas eAD and SIVD groups were impaired on the PAB. The FAB/PAB ratio further differentiated the groups (F(3,85) = 26.49, P < .001). For sensitivities and specificities of 93%, a cut-off score of 1.25 on the FAB/PAB distinguished eAD, and a cut-off of 0.83 distinguishing FTD.

CONCLUSION

Although preliminary, this study indicates that mental status screening based on frontal versus posterior cortical functions may help clinicians diagnose EODs.

Prevalence and causes of early-onset dementia in Japan: a population-based study

BACKGROUND AND PURPOSE

Few studies are available that have addressed the prevalence of early-onset dementia (EOD), including early-onset Alzheimer disease and other forms of dementia in Japan.

METHODS

A 2-step postal survey was sent to all of the 2475 institutions providing medical or care services for individuals with dementia in Japan's Ibaraki prefecture (population, 2 966 000) requesting information on EOD cases. Data were then reviewed and collated.

RESULTS

We identified 617 subjects with EOD. The estimated prevalence of EOD in the target population was 42.3 per 100 000 (95% CI, 39.4 to 45.4). Of the illnesses that cause EOD, vascular dementia was the most frequent (42.5%) followed by Alzheimer disease (25.6%), head trauma (7.1%), dementia with Lewy bodies/Parkinson disease with dementia (6.2%), frontotemporal lobar degeneration (2.6%), and other causes (16.0%).

CONCLUSIONS

The prevalence of EOD in Japan appeared to be similar to that in Western countries with the notable exception that vascular dementia was the most frequent cause of EOD in Japan.

Characteristics and diagnostic profile of patients seeking dementia care in a memory clinic in Hong Kong

BACKGROUND

Seeking medical advice for dementia involves an understanding of norms, values and attitudes towards care-giving and inter-dependency, which are culturally bounded. We hypothesize that local culture and socioeconomic structure affect our Chinese patients who present with forgetfulness to our memory clinic.

METHODS

A retrospective case notes review was undertaken on 454 consecutive patients referred to the memory clinic at Princess Margaret Hospital, Hong Kong.

RESULTS

385 patients were diagnosed with dementia and 27 had mild cognitive impairment. Reversible dementia was identified in 24 patients and normal cognition in 18. In patients with dementia, 55.8% had Alzheimer's disease, 26.2% had vascular dementia, 6.0% had other irreversible dementia, 5.2% had dementia with Lewy bodies, 4.9% had undetermined dementia and 1.8% had frontotemporal dementia. The median duration from symptom onset to medical consultation was two years; 66.5% had advanced disease with initial Mini-mental State Examination scores < or = 17. On their first visit, 85% of patients were living in the community; after two years this proportion had fallen to 63%.

CONCLUSIONS

Dementia patients in Hong Kong apparently enjoy a long subclinical period and only seek medical attention at late stages. Local Chinese culture and socioeconomic backgrounds could be the main reasons that underlie these observations.

Early onset dementia

Dementia is characterized by a decline in cognitive faculties and occurrence of behavioral abnormalities which interfere with an individual's activities of daily living. Dementing disorders usually affect elderly individuals but may occur in individuals younger than 65 years (early-onset dementia or EOD). EOD is often misdiagnosed or its diagnosis is delayed due to the fact that it has a more varied differential diagnosis than late-onset dementia. EOD affects individuals at the height of their career and productivity and produces devastating consequences and financial loss for the patient's family as well as society. EOD is not uncommon and is diagnosed in up to a third of patients presenting with dementia. Most importantly, some of the causes of EOD are curable which makes the need for a specific and timely diagnosis crucial. The present chapter presents a systematic approach to the differential diagnosis of EOD and provides readers with the clinical and neuroimaging features of these disorders as well as important considerations for their diagnostic evaluation. Specifically, the nuances of assessing the history and examination are discussed with careful attention to the various methods of cognitive and behavioral evaluation. A step-wise approach to diagnostic testing is followed by a discussion of anatomical localization, which often aids in identifying specific etiologies. Finally, in order to organize the subject for the reader, the various etiologies are grouped under the general categories of vascular, infectious, toxic-metabolic, immune-mediated, neoplastic/metastatic, and neurodegenerative.