Usefulness of p300 in subjective memory complaints: a prospective study.

The existing studies about the utility of P300 latency for diagnostically classifying patients in preclinical stages of dementia are cross-sectional rather than longitudinal in design, and their results are inconclusive. The authors investigated the P300 value in a series of patients with subjective memory complaints using a prospective design. The study was performed in a consecutive series of 116 outpatients with subjective memory complaints as the predominant symptom. P300 (auditory oddball task) was performed immediately after the first clinical evaluation, and at 12 and 24 months. Final cognitive syndrome diagnosis (mean follow-up period, 27.7 months) was then made by a neurologist who was blinded to the neurophysiologic results. Diagnosis at the end of follow-up was 30 cases of normal cognition, 30 cases of mild cognitive impairment, 28 cases of dementia of Alzheimer's type (DAT), five cases of vascular dementia, and one case of frontotemporal dementia; 22 patients were lost to follow-up. P300 latency was significantly higher for the DAT group (analysis of variance: P=0.023) throughout the study. The diagnostic value of P300 latency at baseline examination for DAT had a sensitivity of 52.9% and a specificity of 76.9%; the odds ratio was 3.75 (95% confidence interval, 1.23-11.41). Findings from the present study suggest that assessment of evoked related potentials may contribute to the early detection of DAT.

Preclinical memory profile in Alzheimer patients with and without allele APOE-epsilon4.

To investigate the association between APOE-epsilon4 allele and memory phenotype in the preclinical stage of Alzheimer's disease (AD). We compared an extensive preclinical memory profile at the baseline evaluation of 2 AD genotype groups: APOE-epsilon4 allele carriers and patients with APOE-epsilon3 homozygosity. Baseline memory performance was carried out at least 2 years (interval of 27.7 +/- 4 months) before AD diagnosis was established, and analysis included different modalities of working memory (visuoperceptive, visuospatial, digit span and processing speed), of declarative memory (recent, verbal learning, prospective and semantic) and of nondeclarative memory (procedural, incidental and priming). We found no significant differences: memory performance was similar in both genotype groups. The presence of the APOE-epsilon4 allele does not seem to be sufficient to cause a distinctive preclinical memory phenotype in AD patients.

Semantic knowledge of famous people in mild cognitive impairment and progression to Alzheimer's disease.

Patients with dementia of Alzheimer's type (DAT) show severe impairment in recognizing famous people. The aim of the current study was to investigate if this well-known memory impairment of famous faces is already present in the preclinical phase of DAT and if the famous faces test can help to differentiate patients with mild cognitive impairment (MCI) who progress to dementia and those who do not. We compared baseline performance in a task of famous face identification in a sample of 116 patients with subjective memory complaints classified in three groups: 17 participants with no evidence of cognitive impairment; 26 patients with MCI who had not developed dementia, and 27 patients with MCI who had developed probable DAT 2 years later. The remaining patients were excluded because they abandoned or did not meet the applied restrictive criteria for DAT, MCI or control. MCI patients who were diagnosed 2 years later with DAT performed significantly worse in the preclinical phase than MCI and control participants (p < 0.004). Patients with MCI but not DAT obtained intermediate results between control subjects and MCI patients who develop Alzheimer's disease. A neuropsychological task of semantic knowledge of famous people may be useful in the early diagnosis of Alzheimer's disease.

Rey verbal learning test is a useful tool for differential diagnosis in the preclinical phase of Alzheimer's disease: comparison with mild cognitive impairment and normal aging.

OBJECTIVE: To confirm that performance in verbal learning and memory test (Rey's Auditory Verbal Learning Test-RAVLT) is a helpful early neuropsychological marker of dementia of Alzheimer's type (DAT). METHODS: RAVLT was administered as part of a more extensive neuropsychological battery at baseline evaluation in 116 unselected patients referred by subjective memory complaints (SMC). Patients were followed longitudinally for 2 years (average interval of 27.7+/-4 months). Seventy patients were included in the study: 27 developed probable DAT; 17 were diagnosed as cognitively normal persons and 26 were diagnosed with Mild Cognitive Impairment (MCI). Remaining patients abandoned or they did not meet the criteria for DAT, MCI or control. Performance on RAVLT at the baseline evaluation was compared between groups. RESULTS: Patients diagnosed two years later with probable DAT showed lower results, more frequently performed a score of zero at the delayed recall test (Trial 6) and had a percentage of forgetting (difference between Trials 5 and 6) higher than 75%. Score at delayed recall test and percentage of forgetting correlated with functional scales such as MMSE, Geriatric Depression Screening, Informant Questionnaire and Blessed's Dementia Rating. CONCLUSIONS: RAVLT could help to identify those patients with SMC who would progress to DAT over a few years, and also to differentiate between the preclinical phase of Alzheimer's disease, mild cognitive impairment and normal aging. A score of zero at the delayed recall test or a percentage of forgetting > or =75% in patients with SMC is suggestive of probable DAT in the future.

Quantitative signal intensity measures on magnetic resonance imaging in attention-deficit hyperactivity disorder.

OBJECTIVE: The aim of this study was to investigate possible abnormalities of cerebral myelination in subjects with attention-deficit hyperactivity disorder (ADHD). BACKGROUND: Anatomic and functional neuroimaging studies of subjects with ADHD demonstrated a right frontostriatal deficit and abnormal cerebral asymmetries. Some also reported white matter abnormalities, such as smaller white matter volumes in the right anterior-superior frontal region, and the smaller bilateral retrocallosal region. Smaller volumes in specific areas of the corpus callosum have also been reported. We hypothesized that white matter signal intensities may also show differences indicating abnormal cerebral myelination. METHOD: We analyzed T2-weighted magnetic resonance images of 11 adolescents with ADHD and 20 controls. Regions of interest were set in both the white and gray matter in frontal and parieto-occipital associative regions. RESULTS: The ADHD group showed a higher signal intensity ratio, probably reflecting a higher degree of myelination. Significant interhemispheric differences emerged only in the posterior region in the ADHD group. CONCLUSIONS: The higher degree of myelination in the right frontal region of ADHD may be due to a compensatory mechanism for the right frontostriatal dysfunction.

Estimulación cognitiva en el envejecimiento y la demencia / Cognitive stimulation in aging and dementia

La estimulación cognitiva se define como una intervención terapéutica de apoyo en el envejecimiento y complementaria al tratamiento farmacológico en la demencia. Esta revisión tiene como objetivo acercarnos a las diferentes estrategias y de intervención cognitiva como respuesta terapéutica al envejecimiento cognitivo y la demencia (AU)