EEG microstate complexity for aiding early diagnosis of Alzheimer's disease.

The dynamics of the resting brain exhibit transitions between a small number of discrete networks, each remaining stable for tens to hundreds of milliseconds. These functional microstates are thought to be the building blocks of spontaneous consciousness. The electroencephalogram (EEG) is a useful tool for imaging microstates, and EEG microstate analysis can potentially give insight into altered brain dynamics underpinning cognitive impairment in disorders such as Alzheimer's disease (AD). Since EEG is non-invasive and relatively inexpensive, EEG microstates have the potential to be useful clinical tools for aiding early diagnosis of AD. In this study, EEG was collected from two independent cohorts of probable AD and cognitively healthy control participants, and a cohort of mild cognitive impairment (MCI) patients with four-year clinical follow-up. The microstate associated with the frontoparietal working-memory/attention network was altered in AD due to parietal inactivation. Using a novel measure of complexity, we found microstate transitioning was slower and less complex in AD. When combined with a spectral EEG measure, microstate complexity could classify AD with sensitivity and specificity > 80%, which was tested on an independent cohort, and could predict progression from MCI to AD in a small preliminary test cohort of 11 participants. EEG microstates therefore have potential to be a non-invasive functional biomarker of AD.

Multiple sclerosis in the Republic of San Marino, Italian peninsula: an incidence and prevalence study from a high-risk area.

Epidemiological studies on multiple sclerosis (MS) carried out in Southern Europe in the last years have shown a significant increase in the disease frequency. Previous surveys conducted in the Republic of San Marino, Northern Italian peninsula, identified that the population is at high risk for MS, with a prevalence of 51.6 per 100,000 population in 1982 and of 166.7 in 2005 and with a mean annual incidence of 7.9 per 100,000 for the period 1990-2005. The present work is a community-based intensive prevalence and incidence survey, by a complete enumeration approach, to update the prevalence and incidence of MS in the Republic of San Marino. The mean annual incidence for the period 2005-14 was 7.7 (95% CI 4.9-11.4) per 100,000, 3.3 (95% CI 1.1-7.6) for men and 11.9 (95% CI 7.2-18.6) for women. On 31 December 2014, 67 patients (19 men and 48 women), suffering from definite or probable MS and living in the Republic of San Marino, yielded a crude prevalence of 204.3 (95% CI 158.4-259.5) per 100,000, 117.8 (95% CI 70.9-183.7) for men and 288.2 (95% CI 212.4-383.3) for women. Our study has confirmed San Marino is an area at high risk for MS, in line with epidemiological data from continental Italy. The marked increase in MS prevalence over time in this population can be ascribable to increased survival and improved ascertainment, in the presence of a substantially stable, yet high, incidence rate.