A New Wearable System for Home Sleep Apnea Testing, Screening, and Classification

We propose an unobtrusive, wearable, and wireless system for the pre-screening and follow-up in the domestic environment of specific sleep-related breathing disorders. This group of diseases manifests with episodes of apnea and hypopnea of central or obstructive origin, and it can be disabling, with several drawbacks that interfere in the daily patient life. The gold standard for their diagnosis and grading is polysomnography, which is a time-consuming, scarcely available test with many wired electrodes disseminated on the body, requiring hospitalization and long waiting times. It is limited by the night-by-night variability of sleep disorders, while inevitably causing sleep alteration and fragmentation itself. For these reasons, only a small percentage of patients achieve a definitive diagnosis and are followed-up. Our device integrates photoplethysmography, an accelerometer, a microcontroller, and a bluetooth transmission unit. It acquires data during the whole night and transmits to a PC for off-line processing. It is positioned on the nasal septum and detects apnea episodes using the modulation of the photoplethysmography signal during the breath. In those time intervals where the photoplethysmography is detecting an apnea, the accelerometer discriminates obstructive from central type thanks to its excellent sensitivity to thoraco-abdominal movements. Tests were performed on a hospitalized patient wearing our integrated system and the type III home sleep apnea testing recommended by The American Academy of Sleep Medicine. Results are encouraging: sensitivity and precision around 90% were achieved in detecting more than 500 apnea episodes. Least thoraco-abdominal movements and body position were successfully classified in lying down control subjects, paving the way toward apnea type classification.

Intracranial Tumour Characterization: Whole Brain Evaluation with MR Perfusion Images and SPECT-CT

A comparative study between perfusion magnetic resonance (MR) imaging and single photon emission tomography - computed tomography (SPECT-CT) was performed to disclose the indications and limits of the two techniques for brain tumour characterization. We compared these two techniques because they evaluate the entire brain and often a brain tumour can be too large to be studied entirely with MR spectroscopy. Forty-three patients with 56 lesions were studied with both techniques. The sensitivity in identifying neoplastic tissue was achieved. We did not evaluate the diagnostic sensitivity to differentiate high grade from low-grade tumours because the features of grade II astrocytomas with SPECT-methoxyisobutylisonitrile (SPECT-MIBI) are similar to those of normal brain tissue. Another question that advanced diagnostic techniques can solve is real glioma extension, but we did not consider also this aspect due to the low SPECT-MIBI spatial resolution. In 29 (29/56) cases both techniques accurately identified the presence of neoplastic tissue. Only SPECT-CT was positive in eight cases, whereas perfusion MR was falsely negative. Only perfusion MR identified tumoral tissue in four cases and SPECT-CT not. Finally both perfusion MR and SPECT-CT failed to identify neoplastic tissue in 15 cases out of 56. In most cases the diagnostic gain of both techniques was the same. One technique was superior to the other in only in a few cases. We conclude that, if available, both techniques can be used to study suspected brain tumours to better characterize the lesion.

Cerebrospinal fluid neuron-specific enolase in Alzheimer's disease and vascular dementia

Levels of neuron-specific enolase (NSE), a glycolytic enzyme localized in neurons, were measured in serum and cerebrospinal fluid (CSF) of patients with early-onset (e-AD) and late-onset (l-AD) Alzheimer's disease, vascular dementia (VD) and controls. Mean CSF NSE levels in patients with Alzheimer's disease did not significantly differ from those in controls, although in the AD group a correlation was found between NSE levels and severity of cognitive deficits. In VD patients, CSF NSE was lower than in controls or in AD patients. These findings are of physiopathological interest but suggest that CSF NSE is not a useful biological marker in dementia disorders.