Phonological fluency norms for Spanish middle-aged and older adults provided by the SCAND initiative (P, M, & R).

OBJECTIVE: Verbal fluency tests are quick and easy to administer neuropsychological measures and are regularly used in neuropsychological assessment. Additionally, phonological fluency is a widely used paradigm that is sensitive to cognitive impairment. This paper offers normative data of phonological verbal fluency (letters P, M, R) for Spanish middle- and older-aged adults, considering sociodemographic factors, and different measures such as the total number of words, errors (perseveration and intrusions), and 15 sec-segmented scores. METHOD: A total of 1165 cognitively unimpaired participants aged between 50 and 89 years old, participated in the study. Data for P were obtained for all participants. Letters M and R were also administered to a subsample of participants (852) aged 60 to 89 years. In addition, errors and words produced every 15 seconds were collected in the subsample. To verify the effect of sociodemographic variables, linear regression was used. Adjustments were calculated for variables that explained at least 5% of the variance (R2 ≥ .05). RESULTS: Means and standard deviations by age, scaled scores, and percentiles for all tests across different measures are shown. No determination coefficients equal to or greater than .05 were found for sex or age. The need to establish adjustments for the educational level was only found in some of the measures. CONCLUSIONS: The current norms provide clinically useful data to evaluate Spanish-speaking natives from Spain aged from 50 to 89 years. Specific patterns of cognitive impairment can be analyzed using these normative data and may be important in neuropsychological assessment.

Functional Connectivity Hypersynchronization in Relatives of Alzheimer's Disease Patients: An Early E/I Balance Dysfunction?

Alzheimer's disease (AD) studies on animal models, and humans showed a tendency of the brain tissue to become hyperexcitable and hypersynchronized, causing neurodegeneration. However, we know little about either the onset of this phenomenon or its early effects on functional brain networks. We studied functional connectivity (FC) on 127 participants (92 middle-age relatives of AD patients and 35 age-matched nonrelatives) using magnetoencephalography. FC was estimated in the alpha band in areas known both for early amyloid accumulation and disrupted FC in MCI converters to AD. We found a frontoparietal network (anterior cingulate cortex, dorsal frontal, and precuneus) where relatives of AD patients showed hypersynchronization in high alpha (not modulated by APOE-ε4 genotype) in comparison to age-matched nonrelatives. These results represent the first evidence of neurophysiological events causing early network disruption in humans, opening a new perspective for intervention on the excitation/inhibition unbalance.

Alpha band disruption in the AD-continuum starts in the Subjective Cognitive Decline stage: a MEG study.

The consideration of Subjective Cognitive Decline (SCD) as a preclinical stage of AD remains still a matter of debate. Alpha band alterations represent one of the most significant changes in the electrophysiological profile of AD. In particular, AD patients exhibit reduced alpha relative power and frequency. We used alpha band activity measured with MEG to study whether SCD and MCI elders present these electrophysiological changes characteristic of AD, and to determine the evolution of the observed alterations across AD spectrum. The total sample consisted of 131 participants: 39 elders without SCD, 41 elders with SCD and 51 MCI patients. All of them underwent MEG and MRI scans and neuropsychological assessment. SCD and MCI patients exhibited a similar reduction in alpha band activity compared with the no SCD group. However, only MCI patients showed a slowing in their alpha peak frequency compared with both SCD and no SCD. These changes in alpha band were related to worse cognition. Our results suggest that AD-related alterations may start in the SCD stage, with a reduction in alpha relative power. It is later, in the MCI stage, where the slowing of the spectral profile takes place, giving rise to objective deficits in cognitive functioning.