Odor identification in mild cognitive impairment subtypes

The current study examined odor identification using the Brief Smell Identification Test (BSIT) in mild cognitive impairment (MCI) subtypes (17 "amnestic MCI", 46 "amnestic-plus MCI", and 25 "MCI other"). Performance in participants with MCI was compared to that of participants with Alzheimer's disease (AD, n=44) and healthy elderly (n=21). MCI participants performed worse than controls, but better than those with AD. MCI subtypes did not differ. The magnitude of difference between MCI participants and controls was modest, raising some question of the clinical utility of the BSIT in early detection of MCI and early differential diagnosis.     

Brain SPECT in subtypes of mild cognitive impairment

The Development of Screening Guidelines and Clinical Criteria of Predementia Alzheimer's Disease (DESCRIPA) multicenter study enrolled patients with MCI or subjective cognitive complaints (SUBJ), a part of whom underwent optional brain perfusion SPECT. These patients were classified as SUBJ (n = 23), nonamnestic MCI (naMCI; n = 17) and amnestic MCI (aMCI; n = 40) based on neuropsychology. Twenty healthy subjects formed the control (CTR) group. Volumetric regions of interest (VROI) analysis was performed in six associative cortical areas in each hemisphere. ANOVA for repeated measures, corrected for age and center, showed significant differences between groups (p = 0.01) and VROI (p < 0.0001) with a significant group-region interaction (p = 0.029). In the post hoc comparison, SUBJ did not differ from CTR. aMCI disclosed reduced uptake in the left hippocampus and bilateral temporal cortex (compared with CTR) or in the left hippocampus and bilateral parietal cortex (compared with SUBJ). In the naMCI group, reduced VROI values were found in the bilateral temporal cortex and right frontal cortex. In the comparison between aMCI and naMCI, the former had lower values in the left parietal cortex and precuneus. Discriminant analysis between SUBJ/CTR versus all MCI patients allowed correct allocations in 73 % of cases. Mean VROI values were highly correlated (p < 0.0001) with the learning measure of a verbal memory test, especially in the bilateral precunei and parietal cortex and in the left hippocampus. In a subset of 70 patients, mean VROI values showed a significant correlation (p < 0.05) with the white matter hyperintensities score on MRI. In conclusion, MCI subtypes have different perfusion patterns. The aMCI group exhibited a pattern that is typical of early Alzheimer's disease, while the naMCI group showed a more anterior pattern of hypoperfusion. Instead, a homogeneous group effect was lacking in SUBJ.     

Stability of neurocognitive impairment in different subtypes of mild cognitive impairment

There has been increasing interest in delineating different cognitive subtypes of mild cognitive impairment (MCI). It remains unclear, however, the extent to which neuropsychological impairment associated with amnestic, nonamnestic, and amnestic+ subtypes of MCI remains stable over time. In this study, 70 persons meeting the criteria for MCI and 38 cognitively normal elderly subjects received a baseline neuropsychological evaluation and were reevaluated 1 year later. Our results indicated that 84.6% of the persons initially classified as amnestic, 75% of those classified as nonamnestic, and 80% of the persons classified as MCI+ evidenced stable or more pronounced neuropsychological impairment across the follow-up period. Less than 7% of the amnestic and amnestic+ cases had nonimpaired neuropsychological profiles at their reevaluation at 12 months, and 16.7% of the nonamnestic cases had nonimpaired neuropsychological test profiles at follow-up. Approximately 87% of the cognitively normal subjects at baseline continued to have unimpaired neuropsychological performance at follow-up. These results indicate that the presence of neuropsychological impairment is relatively stable over a 12-month follow-up period among different cognitive subtypes of MCI, although 15-25% of the cases did not exhibit the specific cognitive deficits that characterized their performance at baseline.     

Evaluation of mild cognitive impairment subtypes in Parkinson's disease

Mild cognitive impairment in Parkinson's disease (PD‐MCI) is common and increases the risk for dementia. Establishing distinct PD‐MCI cognitive subtypes could be valuable for eventually predicting those most likely to convert to dementia. However, the study of PD‐MCI subtypes has not yielded consistent results among cohorts. To determine whether there are distinct cognitive subtypes among participants diagnosed with PD‐MCI in the Pacific Northwest Udall Center Clinical Consortium, we cognitively subtyped 95 patients with PD‐MCI, using the Movement Disorders Society Task Force diagnostic guidelines. Psychometric test scores were then subjected to principle components factor analysis to determine whether similar cognitive subgroups could be identified using statistical methodology. Multiple‐domain PD‐MCI was diagnosed in 95% of the sample, and a range of cognitive impairments were noted. Factor analysis yielded seven factors and demonstrated overlap of phonemic verbal fluency on two factors, as well as the loading of verbal fluency on the same factor as a visuospatial measure; however, these factors did not partition the sample into distinct cognitive subtypes. Separation of cognitive subtypes based on the current PD‐MCI criteria, or via statistical methods, may not provide sufficient information to describe distinct PD groups. Future efforts to validate the PD‐MCI criteria and identify combinations of genetic or other risk factors for cognitive impairment are warranted. © 2014 International Parkinson and Movement Disorder Society     

两种遗忘型轻度认知损害患者的随访比较

目的 比较单纯遗忘型轻度认知功能损害(aMCI-s)和多个认知领域损害遗忘型轻度认知功能损害(aMCI-m)患者的2年随访转归结果并分析其神经心理学变化.方法 采用MMSE、听觉词语学习测验(AVLT)、逻辑回忆测验(LMT)、连线测验(TMT)、Stroop色词测验(CWT)、Rey复杂图形测验(CFT)、五点连线测验(FPT)、画钟测验(CDT)、言语流畅性测验(VF)和临床痴呆量表(CDR)等一系列神经心理测验评估记忆障碍门诊130例遗忘型轻度认知功能损害(aMCI)就诊者(其中aMCI-s 66例和aMCI-m 64例),并进行平均2年的随访,MCI及AD的诊断标准分别参照美国Petersen等及美国神经病学、语言障碍和卒中-老年性痴呆和相关疾病学会(NINCDS-ADRDA)有关诊断标准.结果 aMCI的阿尔茨海默病(AD)总转化率为33.8%(44/130);aMCI-s和aMCI-m的AD转化率分别为26.2%(17/65)和42.9%(27/63),差异有统计学意义(x2=3.957,P=0.047).随着aMCI发展为AD,aMCI-s和aMCI-m组在记忆和执行功能方面的减退幅度接近,aMCI-s组的视空间结构能力相对保留,语言和注意力的减退更快,aMCI-m组的视空间结构能力衰退更为显著.结论 aMCI-m比aMCI-s更容易发展为AD,aMCI分为aMCI-s和aMCI-m对判断认知功能减退的速度是有必要的,有助于判断预后.     

Gray matter atrophy patterns of mild cognitive impairment subtypes

Mild cognitive impairment (MCI) is a heterogeneous neurocognitive disorder that can be classified into various subtypes. The present study aims to examine the gray matter (GM) atrophy patterns of MCI subtypes in comparison with a cognitively healthy group. Participants, including 135 MCI subjects and 120 cognitively healthy controls, were drawn from the Sydney Memory and Ageing Study. The MCI subjects were first categorized into amnestic (aMCI) and non-amnestic (naMCI) subtypes, which were then divided into single-domain (aMCI-SD and naMCI-SD) and multiple-domain subtypes (aMCI-MD and naMCI-MD). Furthermore, naMCI-SD was divided into three subgroups (language, processing speed, and executive function) according to individual cognitive impairment. Voxel-wise GM volumes were then compared between MCI subtypes and controls. The aMCI group had significantly lower GM volumes in the bilateral hippocampi and temporal cortices than the controls. This was mainly due to GM reduction of aMCI-MD but not aMCI-SD, as the latter did not show any significant GM reduction. GM reduction of naMCI and its two subdivisions was shown in widespread brain regions compared to controls. GM volumes of the multiple-domain subtypes (aMCI-MD and naMCI-MD) were lower than their single-domain counterparts (aMCI-SD and naMCI-SD) in the frontal and temporal lobes, respectively. Moreover, the language subgroup of naMCI-SD showed GM reduction in the frontal and temporal lobes compared to controls. MCI subtypes displayed specific patterns of GM atrophy that appear to be related to their various clinical presentations, which implies that underlying mechanisms of MCI subtypes are different.     

不同亚型轻度认知功能损害患者的神经心理学特征

目的 探讨不同亚型轻度认知功能损害(MCI)患者的神经心理学特征.方法 采用多种神经心理学量表对28例遗忘型MCI (aMCI)、21例血管型MCI (V-MCI)、21例帕金森病型MCI(PD-MCI)及46名健康老年人进行评定,比较不同亚型MCI的神经心理学特征.结果 (1)与健康对照组比较,各亚型MCI组在总体认知评分及剑桥老年认知检查量表中文版(CAMCOG-C)子项评分差异均有统计学意义.aMCI组在定向、语言表达、近记忆、学习记忆、注意、计算、思维及知觉方面均受损,差异具有统计学意义(t=4.580、5.150、3.053、4.070、5.918、2.121、2.952、3.175,均P＜0.05);语言理解、远记忆与执行能力相对保留,差异无统计学意义.V-MCI组定向、语言表达、注意与执行功能受损(t=2.974、3.165、4.216、3.197,均P＜0.05),记忆力、计算、思维及知觉较对照组差异无统计学意义.PD-MCI组在语言表达、近记忆、远记忆、学习记忆、注意及执行功能方面损害均显著,差异具有统计学意义(t=4.433、3.065、3.821、3.447、5.344、0.348,均P＜0.05).(2)各亚型MCI组间比较:与V-MCI组[(3.52±0.87)分、(12.48±1.83)分]相比,aMCI组[(3.07±0.81)分、(11.07±2.28)分]与PD-MCI组[(3.00 ±0.89)分、(11.33 ±1.91)分]在CAMCOG-C总体评分及其子项中记忆能力包括近记忆、学习记忆降低显著,差异具有统计学意义(aMCI与V-MCI比较t=1.868、2.381,PD-MCI与V-MCI比较t=1.921、1.980;均P＜0.05).PD-MCI组中,远记忆及执行功能较其他两组显著降低,差异具有统计学意义(与aMCI比较t=2.498、4.257,与V-MCI比较t=1.684、1.492:均P＜0.05).(3)aMCI组GDS评分较健康对照组显著增高,差异具有统计学意义(t=2.850,P＜0.05),而V-MCI组及PD-MCI组与健康对照组比较差异均无统计学意义,但aMCI组及V-MCI组GDS得分较PD-MCI组增高.结论 3种不同亚型MCI认知损害均为多区域性,aMCI主要表现为记忆损害,V-MCI以执行功能损害为主,PD-MCI记忆及执行功能均受损;aMCI较其他亚型更易出现抑郁倾向.不同亚型MCI神经心理学特征的不同,反映了不同的病理生理学机制.     

Clinical differences among mild cognitive impairment subtypes in Parkinson's disease

Mild cognitive impairment is increasingly recognized as a construct in Parkinson's disease (PD) and occurs in about 25% of nondemented PD patients. Although executive dysfunction is the most frequent type of cognitive deficit in PD, the cognitive phenotype of PD mild cognitive impairment (PD-MCI) is broad. PD-MCI subtypes are represented by amnestic and nonamnestic domain impairment as well as single- and multiple-domain impairment. However, it is unclear whether patients with different PD-MCI subtypes also differ in other clinical characteristics in addition to cognitive profile. We studied 128 PD-MCI subjects at our Movement Disorders center, comparing clinical, motor, and behavioral characteristics across the PD-MCI subtypes. We found varying proportions of impairment subtypes: nonamnestic single domain, 47.7%; amnestic multiple domain, 24.2%; amnestic single domain, 18.8%; and nonamnestic multiple domain, 9.5%. Attentional/executive functioning and visuospatial abilities were the most frequently impaired domains. PD-MCI subtypes differed in their motor features, with nonamnestic multiple-domain PD-MCI subjects showing particularly pronounced problems with postural instability and gait. Differences among PD-MCI subtypes in age, PD duration, medication use, mood or behavioral disturbances, and vascular disease were not significant. Thus, in addition to differing cognitive profiles, PD-MCI subtypes differed in motor phenotype and severity but not in mood, behavioral, or vascular comorbidities. Greater postural instability and gait disturbances in the nonamnestic multiple-domain subtype emphasize shared nondopaminergic neural substrates of gait and cognition in PD. Furthermore, increased burden of cognitive dysfunction, rather than type of cognitive deficit, may be associated with greater motor impairment in PD-MCI. ? 2012 Movement Disorder Society.     

Progression to dementia in clinical subtypes of mild cognitive impairment

OBJECTIVE: To examine the outcome among patients diagnosed with different types of mild cognitive impairment (MCI). PATIENTS: A follow-up examination (average follow-up period: 3.49 +/- 2.2 years) was performed in 81 cognitively impaired, non-demented patients aged >55 years at baseline. RESULTS: 8 of 32 patients with amnestic MCI (25%), 22 of 41 patients with multiple-domain MCI (54%), and 3 of 8 patients with single non-memory MCI (37.5%) progressed to dementia. The clinical type of MCI is significantly associated with the likelihood of conversion to dementia. DISCUSSION: When the clinical syndrome of MCI evolves on a neurodegenerative basis, the multiple-domain type of MCI has a less favorable prognosis than the amnestic type and may represent a more advanced prodromal stage of dementia.     

Hippocampal shape and cognitive performance in amnestic mild cognitive impairment

Previous studies have carried out hippocampal shape analysis of amnestic mild cognitive impairment (aMCI) patients using automated segmentation techniques. However, the relationships between hippocampal deformations and various episodic memory impairments were not clear. The aim of this study was to investigate hippocampal shape changes and their relationships with various episodic memory impairments in aMCI. Hippocampal volumes and deformations were compared between the aMCI and the controls. In addition, we explored the correlation pattern between hippocampal deformations and cognitive dysfunctions in aMCI using a comprehensive neuropsychological battery. Patients with aMCI exhibited significant hippocampal deformations in the right cornu ammonis 1 (CA1) and subiculum areas compared with healthy individuals. Significant correlations were observed between constructional recall scores and the right CA1 and subiculum areas in aMCI. Verbal delayed recall scores were also significantly correlated with the left CA1 and subiculum areas in aMCI. This study was the first to explore the relationships between hippocampal deformations and various types of cognitive performances in aMCI. These structural changes in the hippocampal CA1 and subiculum areas might be at the core of underlying neurobiological mechanisms of hippocampal dysfunction and their relevance to verbal and visuospatial delayed recall in aMCI.     

Conversion of mild cognitive impairment to dementia: predictive role of mild cognitive impairment subtypes and vascular risk factors

Mild cognitive impairment (MCI) is regarded as a precursor to dementia, but not all patients with MCI develop dementia. We followed up 165 elderly outpatients with MCI for a mean of 3 years. The aims were (1) to investigate the risk of conversion to dementia for different MCI subtypes diagnosed according to standardized criteria (amnestic; impairment of memory plus other cognitive domains; nonamnestic); (2) to assess whether the risk of conversion was affected by several established and emerging vascular risk factors. Forty-eight subjects (29%) converted to dementia, and the risk of conversion was doubled for amnestic MCI with respect to the other subtypes. Independently of MCI subtype, risk of conversion was associated with atrial fibrillation and low serum folate levels. Our results show that current diagnostic criteria for MCI define heterogeneous populations, but some potentially treatable vascular risk factors may be of help in predicting conversion to dementia.     

Predictive validity and diagnostic stability of mild cognitive impairment subtypes

BackgroundMild cognitive impairment (MCI) is subclassified into four subtypes by the presence of impairment in the memory domain (amnestic vs nonamnestic) and the number of impaired cognitive domains (single vs multiple). However, predictive validity for outcomes of these criteria and the diagnostic stability of the subtypes are questionable.MethodsWe investigated the outcomes of 140 patients with MCI who participated in the baseline study of the Korean Longitudinal Study on Health and Aging and completed the 18-month follow-up evaluation (mean duration of follow-up = 1.57 ± 0.24 years). We evaluated the predictive validity of the criteria using multinomial logistic regression analyses, and the diagnostic stability of MCI subtypes using annual conversion rates between subtypes.ResultsCompared with the single-domain type (MCIs), the multiple-domain type (MCIm) had a lower chance of reversion to normal cognition (MCIm = 10.94%, MCIs = 43.42%) and higher risk of conversion to dementia (MCIm = 23.44%, MCIs = 5.26%). The difference in the reversion rate between the multiple- and single-domain type was statistically significant (odds ratio = 0.233, 95% confidence interval = 0.070–0.771, P = .017). However, neither the chance of reversion nor the risk of conversion was different between amnestic and nonamnestic subtypes. Among the 81 participants who neither converted to dementia nor reverted to normal cognition, 39 converted to different subtype (annual conversion rate = 17.74%).ConclusionsThe number of impaired cognitive domains, but not the presence of memory impairment, predicted poor outcomes in people with MCI. However, MCI subtype was diagnostically unstable.     

三种亚型轻度认知功能损害横向对比研究

目的对三种亚型轻度认知功能损害(MCI)患者进行量表评定及横向对比研究。方法采用神经心理学量表对21例遗忘型(a-MCI)、19例血管型MCI(v-MCI)和16例酒精依赖型MCI患者以及38名健康对照组(年龄≥60岁)进行比较,比较这几种亚型MCI的神经心理学特点。结果 (1)与健康对照组比较,各亚型的MMSE及CAMCOG—C总体量表评分差异均明显(P0.01)。与健康对照组比较,a-MCI组在近记忆、定向、语言表达、计算、注意、思维方面均受损,差异明显(P均0.05);远记忆、语言理解与执行能力相对保留,差异不明显(P0.05)。与对照组比较,v-MCI组在记忆、定向、语言表达、注意与执行功能均受损(P0.05),语言理解、计算、思维方面与对照组相比差异不明显(P0.05)。酒精依赖型MCI组在近记忆、远记忆、执行、注意及思维功能方面损害有显著性(P均0.05)。定向、语言能力、计算改变不明显;(2)各亚型组间MCI量表评分比较:a-MCI组与v-MCI组相比,CAMCOG—C总体评分及其子项中的近记忆受损显著,差异显著(P0.05);酒精依赖型组与a-MCI组及v-MCI相比,CAMCOG—C总体评分及其子项中的语言能力、计算差异显著,酒精型MCI的语言能力及计算受损较轻;(3)a-MCI组及v-MCI组与健康对照组相比GDS评分显著增高,具有明显差异(P0.05),酒精依赖型MCI组与对照组比较差异不明显(P0.05)。aMCI组及v-MCI组GDS评分高于酒精依赖型MCI组(P0.05)。结论三种不同亚型MCI认知损害均为多区域性,a-MCI主要表现为记忆损害,且以近记忆受损明显;v-MCI以执行功能损害为主,其它多项认知功能均有不同程度损害;酒精依赖型MCI除记忆及执行功能受损外,注意及思维等也不同程度存在损害;aMCI及v-MCI较其他亚型更易出现抑郁倾向。     

Neuropsychological performance in mild cognitive impairment with and without apathy

OBJECTIVE: To investigate the neuropsychological characteristics of patients diagnosed with mild cognitive impairment (MCI) with and without apathy. METHODS: A cohort of 245 MCI patients (mean age = 72 +/- 5.5 years; mean MMSE = 27.5 +/- 1.3) was divided into two subgroups according to their Apathy Inventory score and underwent an extensive neuropsychological battery. RESULTS: There were 94 (38.4%) patients with and 151 (61.6%) patients without apathy. At baseline the apathetic subgroup had a significantly lower total score on the free and cued selective reminding test (FCSR). Furthermore, the apathetic subgroup showed a significant deterioration in FCSR total recall score between baseline and the 1-year assessment. In conclusion, the presence of apathy in MCI patients is not associated with frontal task performance but with a higher degree of memory impairment.