[Introduction and Reflection on Novel Medical Device Regulatory Science Tool MDDT].

In recent years, emerging technology medical devices have developed rapidly. How to more scientifically and more efficiently regulate these novel medical devices so as to improve access to advanced medical technology while ensuring safety and effectiveness is a new challenge faced by regulatory authorities, and is also the core topic of regulatory science. New tools, new standards and new methods are important means to achieve regulatory science. "Medical Device Development Tool" proposed by the U.S. FDA is a novel medical device regulatory science tool, which can help medical device developers to predict and evaluate product performance more efficiently. It is also helpful for regulatory authorities to make regulatory decisions more efficiently. This study introduces the concept, qualification process, role of MDDT in medical device regulation and MDDT examples, and makes some discussion on the device evaluation from the perspective of reliability and validity. MDDT can facilitate the developing of novel medical device.

Approximate entropy analysis of event-related potentials in patients with early vascular dementia.

This study investigated differences in event-related potential (ERP) parameters among early vascular dementia (VD) patients, healthy elder controls (ECs), and young controls (YCs). A visual "oddball" color identification task was performed while individuals' electroencephalograms (EEGs) were recorded. Approximate entropy (ApEn), a nonlinear measure, along with P300 latencies and amplitudes were used to analyze ERP data and compare these three groups. The patients with VD showed more complex ERP waveforms and higher ApEn values than did ECs while performing the visual task. It was further found that patients with VD showed reduced P300 amplitudes and increased latencies. The results indicate that patients with VD have fewer attention resources to devote to processing stimuli, lower speed of stimulus classification, and lower synchrony in their cortical activity during the response period. We suggest that ApEn, as a measure of ERP complexity, is a promising marker for early diagnosis of VD.

Multichannel linear descriptors analysis for event-related EEG of vascular dementia patients during visual detection task.

OBJECTIVE: Multichannel EEG recorded in a task condition could contain more information about cognition. However, that has not been widely investigated in the vascular-dementia (VaD)- related studies. The purpose of this study was to explore the differences of brain functional states between VaD patients and normal controls while performing a detection task. METHODS: Three multichannel linear descriptors, i.e. spatial complexity (Ω), field strength (Σ) and frequency of field changes (Φ), were applied to analyse four frequency bands (delta, theta, alpha and beta) of multichannel event-related EEG signals for 12 VaD patients (mean age ± SD: 69.25 ± 10.56 years ; MMSE score ± SD: 22.58 ± 4.42) and 12 age-matched healthy subjects (mean age ± SD: 67.17 ± 5.97 years ; MMSE score ± SD: 29.08 ± 0.9). The correlations between the three measures and MMSE scores were also analysed. RESULTS: VaD patients showed a significant higher Ω value in the delta (p = 0.013) and theta (p = 0.021) frequency bands, a lower Σ value (p = 0.011) and a higher Φ (p = 0.008) value in the delta frequency band compared with normal controls. The MMSE scores were negatively correlated with the Ω (r = -0.52, p = 0.01) and Φ (r = -0.47, p = 0.02) values in the delta frequency band. CONCLUSIONS: The results indicated the VaD patients presented a reduction of synchronization in the slow frequency band during target detection, and suggested more neurons might be activated in VaD patients compared with normal controls. The Ω and Φ measures in the delta frequency band might be used to evaluate the degree of cognitive dysfunction. SIGNIFICANCE: The multichannel linear descriptors are promising measures to reveal the differences in brain functions between VaD patients and normal subjects, and could potentially be used to evaluate the degree of cognitive dysfunction in VaD patients.

Analysis of propagation of multi-channel EEG in the test of sustained attention.

the psychological construct 'sustained attention' describes a basic component of attention characterized by the subject's readiness to detect rarely and unpredictably occurring signals over prolonged periods of time. In this study, six healthy volunteers underwent a sustained attention to response task (SART), while their electroencephalographic (EEG) were recorded contemporarily. Directed Transfer Function (DTF) was used as estimator for direction of propagation of EEG function coupling. The results of DTF showed that the information flux within EEG functional coupling changed when attention condition changed from inattention state to sustained attention state, principally at alpha and beta rhythms. The DTF could be used to evaluate sustained attention condition and they might be used for research on damage of attention mechanisms of ADHD and TBI diseases in future.