EEG Resting-State Functional Networks in Amnestic Mild Cognitive Impairment.

Background. Alzheimer's cognitive-behavioral syndrome is the result of impaired connectivity between nerve cells, due to misfolded proteins, which accumulate and disrupt specific brain networks. Electroencephalography, because of its excellent temporal resolution, is an optimal approach for assessing the communication between functionally related brain regions. Objective. To detect and compare EEG resting-state networks (RSNs) in patients with amnesic mild cognitive impairment (aMCI), and healthy elderly (HE). Methods. We recruited 125 aMCI patients and 70 healthy elderly subjects. One hundred and twenty seconds of artifact-free EEG data were selected and compared between patients with aMCI and HE. We applied standard low-resolution brain electromagnetic tomography (sLORETA)-independent component analysis (ICA) to assess resting-state networks. Each network consisted of a set of images, one for each frequency (delta, theta, alpha1/2, beta1/2). Results. The functional ICA analysis revealed 17 networks common to groups. The statistical procedure demonstrated that aMCI used some networks differently than HE. The most relevant findings were as follows. Amnesic-MCI had: i) increased delta/beta activity in the superior frontal gyrus and decreased alpha1 activity in the paracentral lobule (ie, default mode network); ii) greater delta/theta/alpha/beta in the superior frontal gyrus (i.e, attention network); iii) lower alpha in the left superior parietal lobe, as well as a lower delta/theta and beta, respectively in post-central, and in superior frontal gyrus(ie, attention network). Conclusions. Our study confirms sLORETA-ICA method is effective in detecting functional resting-state networks, as well as between-groups connectivity differences. The findings provide support to the Alzheimer's network disconnection hypothesis.

Guillain-barré syndrome associated with acute onset bilateral facial nerve palsies. A case report and literature review.

Guillain-Barré syndrome is a post infectious, immune-mediated disease with cranial nerve involvement observed in 45-75% of patients. Bilateral facial nerve palsy is rather uncommon and occurs in 0.3% to 2% of all facial palsies. We describe a rare case of a 29-year-old man with bilateral facial palsy caused by a Guillain-Barré syndrome with an unusual onset and progression of neurological symptoms. Neuroradiological findings in our patient are described and compared with data from literature on bilateral facial palsies to make differential diagnosis easier for neuroradiologists.

Auditory event-related potentials in subcortical vascular cognitive impairment and in Alzheimer's disease.

BACKGROUND: Few studies exist on ERPs and patients with subcortical vascular cognitive impairment (SVCI). This latter is a quite homogeneous subtype of vascular dementia whose cognitive profile is quite different from that of Alzheimer disease (AD). AIMS: The present study aims at comparing the ERPs profile both in patients with SVCI and in patients with AD. SUBJECTS AND METHODS: ERPs and psychometric tests were collected from 39 healthy elderly controls, 51 patients with SVCI and 43 patients with AD. Subjects mentally count high pitched target tones that were randomly intermixed with low pitched frequent tones. We measured ERPs latencies (N1, P2, N2 and P3), and interpeak latencies (N1-P3, N1-P2, N1-N2). RESULTS: Grand averaged potentials in SVCI showed a significant increase of P3 latency. AD patients showed a prolongation of N1, P2, N2, P3 latencies. As far as interpeak latencies are concerned, SVCI patients showed a significant prolongation of N1-P3, AD patients had a significant increase of N1-N2, and N1-P3 intervals. When all patients were considered as a single group, correlation of neuropsychological tests scores showed a significant negative relationship between P300 latency and, respectively, Mini Mental Status Examination, auditive and visual span forward. In both groups, ERPs latency sensitivity, was low, whilst specificity values were quite high. CONCLUSIONS: Our finding suggest that these two dementing diseases have different electrophysiologic features that may be related to their specific underlying pathogenetic mechanism; in particular, we hypothesise that, differently from AD, P300 latency prolongation characterizes the early stage of SVCI. So, this ERPs approach could be helpful to detect early alterations of the attentional/working-memory functions in patients with subcortical ischaemic vascular disease.

Interleukin-18 (IL-18) and matrix metalloproteinase-9 (MMP-9) in post-menopausal osteoporosis.

This survey covered 60 post-menopausal women with osteoporosis. The patients were divided into three equal groups, and each group was treated with one of the three so-called anti-resorptive drugs, namely alendronate (10 mg/day) risedronate (5 mg/day) and raloxifene (60 mg/day) for 12 months. The Elisa technique was used to measure circulating IL-18 and MMP-9. Lumbar bone mineral density (BMD) levels were determined by using dexa mineralometry (Lunar DPX) at baseline and after 12 months of treatment. The results showed comparable responses of the patients treated with alendronate or risedronate, being a significant increase in BMD, an increase in circulating IL-18, and only slight modifications in circulating MMP-9 levels. After 12 months of treatment with raloxifene, there were minimal, non-significant increases in BMD, slight modifications in IL-18 levels, and a significant reduction in circulating MMP-9 levels. The conclusions can be drawn that all three drugs, albeit through different mechanisms, can be considered valid treatments for post-menopausal osteoporosis. Although measurements of circulating IL-8 and MMP-9 levels allowed us to differentiate the effects of the three drugs used, as of today, they have no real role in the diagnosis and/or follow-up of osteoporosis.