Cognitive decline from estimated premorbid status predicts neurodegeneration in Alzheimer's disease.

This study investigated the relationship between premorbid and current cognitive function with respect to the clinical features of patients with various types of neurodegeneration in the form of Alzheimer's disease (AD), mild cognitive impairment (MCI), and subjective cognitive impairment (SCI), as compared with a healthy control group (C). Clinical features (MMSE, cognitive and depressive symptoms), genetics (apolipoprotein E; APOE) and measures of neurodegeneration (Aβ42, t-tau, and p-tau) were examined, as well as present cognitive function. Various methods of assessing premorbid cognitive function were compared, including a Swedish NART-analogous test (Irregularly Spelled Words; ISW), a Swedish lexical decision test (SLDT), a Hold test (Information in WAIS-R), Best current performance test, and combined demographic characteristics. Results showed that cognitive decline (premorbid minus current cognitive function) based on SLDT and ISW was a significant predictor for MMSE and Aβ42, whereas corresponding associations for present cognitive function and decline measures based on other methods were less powerful. Results also showed that specific verbal abilities (e.g., SLDT and ISW) were insensitive to AD and that these abilities indicated premorbid cognitive function in retrospect. In conclusion, cognitive decline from premorbid status reflects the disease processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bilateral temporal lobe volume reduction parallels cognitive impairment in progressive aphasia

BACKGROUND: Patients with isolated aphasia in the absence of other cognitive abnormalities have been the focus of several studies during the past decade. It has been called primary progressive aphasia (PPA), and the typical features of this syndrome are marked atrophy of the left temporal lobe according to the radiological examination and a language disorder as the initial symptom. In previous studies of PPA, the selection of the patients was based mainly on linguistic symptoms. Now, when computed tomography or magnetic resonance imaging scans are part of the routine investigation of cognitive impairment and suspected dementia, the patients with lobar atrophy will be found at an earlier stage. In the present study, we used a new approach and defined the study group by selecting patients with obvious left temporal lobe atrophy, assessed by MRI, and we referred to them as patients with temporal lobe atrophy (TLA). OBJECTIVE: To identify the features that distinguish TLA from other primary neurodegenerative disorders. PATIENTS: Six patients with TLA were compared with patients with Alzheimer disease (AD), patients with frontal lobe dementia (FLD), and healthy control subjects. METHODS: The investigations included magnetic resonance imaging volumetry, single photon emission computed tomography, and neuropsychologic and linguistic evaluations. RESULTS: In the TLA group, the mean volume of the left temporal lobe was 35% smaller than the right, while in the AD and FLD groups, the atrophy was symmetrical and bilateral. In the TLA group, the absolute volumes of the temporal lobes were significantly smaller on the left side compared with the AD and FLD groups, whereas there was no difference on the right side. The cerebral blood flow pattern in TLA was asymmetric and differed from that in the other study groups. All patients with TLA had a history of progressive Wernicke-type aphasia, ranging from 2 to 6 years. They showed primary verbal memory impairment but had preserved visuospatial functions. The clinical condition of all patients with TLA deteriorated during the study period; severe aphasia developed, and the patients exhibited signs of frontal lobe dysfunction. Serial volumetric measurements in 4 of 6 patients showed an annual 8% to 9% decrease of both left and right temporal lobes. CONCLUSIONS: The initial marked asymmetry in cognitive function found in patients with TLA contrasts with the general decline found in patients with AD. The bilateral degenerative process evident in patients with TLA paralleled the clinical deterioration, indicating TLA to be a non-AD lobar atrophy that develops into generalized cognitive dysfunction and dementia.     

Phonemic fluency deficits in asymptomatic gene carriers for Huntington's disease.

The aim of the present study was to investigate verbal fluency in preclinical Huntington's disease (HD). Phonemic and semantic fluency and the rate of word production over time were assessed for 29 asymptomatic gene carriers and 34 noncarriers of HD. The relationship between fluency tasks and other cognitive domains was investigated. Compared to noncarriers, carriers produced fewer words and produced them more slowly in the phonemic fluency task but not in the semantic fluency task. When the carrier group was divided on the basis of Predicted-Years-To-Onset (PYTO), only carriers with     

Cognitive predictors of incident Alzheimer's disease: A prospective longitudinal study.

The present study examined whether cognitive variables measured at baseline could predict incident cases of Alzheimer's disease (AD) after a 3-year follow-up period. Twenty-six incident AD adults and 179 very old (M?=?83.5 years) adults without dementia participated in a population-based study. Cognitive performance was indexed by the Mini-Mental State Examination (MMSE) and multiple indices of memory and visuospatial and verbal performance. A logistic regression analysis that controlled for age, gender, and education indicated that MMSE scores were reliable indicators of who would develop AD. In addition, recall of organizable words, recognition of faces, and letter fluency were reliable predictors of subsequent dementia status after differences in MMSE performance were partialed out. Thus, although the MMSE is useful in predicting dementia, there is an additional advantage of assessing specific indices of cognitive functioning. Further, supportive episodic memory tasks may be more salient predictors of incident AD than tasks that offer less supportive encoding or retrieval conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biased recognition of positive faces in aging and amnestic mild cognitive impairment.

We investigated age differences in biased recognition of happy, neutral, or angry faces in 4 experiments. Experiment 1 revealed increased true and false recognition for happy faces in older adults, which persisted even when changing each face’s emotional expression from study to test in Experiment 2. In Experiment 3, we examined the influence of reduced memory capacity on the positivity-induced recognition bias, which showed the absence of emotion-induced memory enhancement but a preserved recognition bias for positive faces in patients with amnestic mild cognitive impairment compared with older adults with normal memory performance. In Experiment 4, we used semantic differentials to measure the connotations of happy and angry faces. Younger and older participants regarded happy faces as more familiar than angry faces, but the older group showed a larger recognition bias for happy faces. This finding indicates that older adults use a gist-based memory strategy based on a semantic association between positive emotion and familiarity. Moreover, older adults’ judgments of valence were more positive for both angry and happy faces, supporting the hypothesis of socioemotional selectivity. We propose that the positivity-induced recognition bias might be based on fluency, which in turn is based on both positivity-oriented emotional goals and on preexisting semantic associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)