Hideki Kanemoto

A study on modeling of microwave oven interference and optimum reception

The performance of digital radio communication systems is much degraded by the effect of microwave oven interference; therefore, in order to obtain a good error performance under microwave oven interference environment, digital radio communication systems should be designed for this environment. In this paper, using Middletons canonical class-A impulsive noise model, the authors propose a statistical model of microwave oven interference and discuss the performance improvement achieved by an optimum reception based on this statistical model. As a result, the first order statistic of microwave oven interference can he modeled by class-A impulsive radio noise, and a great performance improvement is obtained by using the optimum receiver designed against microwave oven interference with sample interleave scheme.

Functional connectivity assessed by resting state EEG correlates with cognitive decline of Alzheimer’s disease – An eLORETA study

OBJECTIVE To explore neurophysiological biomarkers of Alzheimers disease (AD), we investigated electroencephalography (EEG) of AD patients, and assessed lagged phase synchronization, a measure of brain functional connectivity. METHODS Twenty-eight probable AD patients and 30 healthy controls (HC) were enrolled. Forty seconds of artifact-free EEG data were selected and compared between patients with AD and HC. Current source density (CSD) and lagged phase synchronization were analyzed by using eLORETA. RESULTS Patients with AD showed significantly decreased lagged phase synchronization between most cortical regions in delta band relative to controls. There also was a decrease in lagged phase synchronization between the right dorsolateral prefrontal cortex (DLPFC) and the right posterior-inferior parietal lobule (pIPL) in theta band. In addition, some connections in delta band were found to be associated with cognitive function, measured by MMSE. This involved specifically interhemispheric temporal connections as well as left inferior parietal connectivity with the left hippocampus, lateral frontal regions, and the anterior cingulate cortex (aCC). Right temporal connections in delta band were related to global function, as estimated by CDR. No differences were found in CSD analysis between patients and HC. CONCLUSIONS Functional connectivity disruptions between certain brain regions, as measured with lagged phase synchronization, may potentially represent a neurophysiological biomarker of AD. SIGNIFICANCE Our study indicated that AD and healthy elderly could have the different patterns of lagged phase synchronization.

Statistical model of microwave oven interference and optimum reception

Microwave oven interference seriously degrades the performance of digital radio communication systems, therefore, in order to obtain a good error performance under a microwave oven interference environment, the digital radio communication systems should be newly designed for this environment. In this paper, using the Middletons (1977) canonical class-A impulsive noise model, we propose a statistical model of microwave oven interference and discuss the performance improvement achieved by optimum reception based on this statistical model. Numerical results conclude that the first order statistics of microwave oven interference can be modeled by class-A impulsive radio noise, and a great performance improvement is obtained by using the optimum receiver designed against microwave oven interference with the introduction of the sample interleave scheme.

Differences of Behavioral and Psychological Symptoms of Dementia in Disease Severity in Four Major Dementias

Background/Aims Behavioral and psychological symptoms of dementia (BPSDs) negatively impact the prognosis of dementia patients and increase caregiver distress. The aims of this study were to clarify the differences of trajectories of 12 kinds of BPSDs by disease severity in four major dementias and to develop charts showing the frequency, severity, and associated caregiver distress (ACD) of BPSDs using the data of a Japan multicenter study (J-BIRD). Methods We gathered Neuropsychiatric Inventory (NPI) data of patients with Alzheimer’s disease (AD; n = 1091), dementia with Lewy bodies (DLB; n = 249), vascular dementia (VaD; n = 156), and frontotemporal lobar degeneration (FTLD; n = 102) collected during a 5-year period up to July 31, 2013 in seven centers for dementia in Japan. The NPI composite scores (frequency × severity) of 12 kinds of items were analyzed using a principal component analysis (PCA) in each dementia. The factor scores of the PCA were compared in each dementia by disease severity, which was determined with Clinical Dementia Rating (CDR). Results Significant increases with higher CDR scores were observed in 1) two of the three factor scores which were loaded for all items except euphoria in AD, 2) two of the four factor scores for apathy, aberrant motor behavior (AMB), sleep disturbances, agitation, irritability, disinhibition, and euphoria in DLB, and 3) one of the four factor scores for apathy, depression, anxiety, and sleep disturbances in VaD. However, no increases were observed in any of the five factor scores in FTLD. Conclusions As dementia progresses, several BPSDs become more severe, including 1) apathy and sleep disturbances in AD, DLB, and VaD, 2) all of the BPSDs except euphoria in AD, 3) AMB, agitation, irritability, disinhibition, and euphoria in DLB, and 4) depression and anxiety in VaD. Trajectories of BPSDs in FTLD were unclear.

Sleep disturbances are key symptoms of very early stage Alzheimer disease with behavioral and psychological symptoms: a Japan multi‐center cross‐sectional study (J‐BIRD)

Sleep disturbances in Alzheimer disease (AD) may affect behavioral and psychological symptoms of dementia (BPSD). Our aim was to elucidate the associations between sleep disturbances and other BPSD at different stages of AD.

Association between high biomarker probability of Alzheimer's disease and improvement of clinical outcomes after shunt surgery in patients with idiopathic normal pressure hydrocephalus

We examined the effect of the pathology of Alzheimers disease (AD) on improvement of clinical symptoms after shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH). Forty-four iNPH patients were classified into 18 patients with (iNPH/AD+) and 26 patients without (iNPH/AD-) combination with low amyloid β42 and high total tau in cerebrospinal fluid (CSF). We compared improvements after lumbo-peritoneal shunt surgery (LPS) between the two groups in Timed Up & Go Test, 10-m reciprocating walking test, Digit Symbol Substitution Test, attention test, delayed recall test, Mini-Mental State Examination, iNPH grading scale, Neuropsychiatric Inventory, Zarit Burden Interview, and other evaluations. Three months after LPS, gait, urination, overall cognition, psychomotor speed, attention, and neuropsychiatric symptoms significantly improved in both groups, but the improvement in delayed recall and reduction of caregiver burden were significantly greater in iNPH/AD- than iNPH/AD+. In addition, improvement in delayed recall score after LPS was significantly and negatively correlated with the probability of AD as judged by amyloid β42 and total tau levels in CSF. Three months after LPS, almost all of the triad symptoms decreased in iNPH patients with and without AD pathology but memory improved only in iNPH patients without AD pathology.

Effects of donepezil on sleep disturbances in patients with dementia with Lewy bodies: An open-label study with actigraphy

We investigated whether donepezil, a cholinesterase inhibitor, can be used to treat sleep disturbances in patients with dementia with Lewy bodies (DLB). Sleep disturbances were evaluated with the sleep disturbances item of the Neuropsychiatric inventory (NPI) and an actigraph in 16 DLB patients and 24 normal elderly control (NC) subjects. The presence/absence of nine kinds of sleep symptoms, such as dream enactment, were also evaluated in the DLB patients. The DLB patients were then given 5mg/day donepezil for 14 weeks and evaluated again. Eight of the 16 DLB patients had some sleep disturbances before taking donepezil. The actigraphy data indicated that average activity count per minute in sleep (AAC), which reflects body activity at night, was significantly higher and total sleep time was significantly longer in DLB patients than in NC subjects. The NPI sleep disturbances score significantly improved and the number of DLB patients who had sleep disturbances decreased after taking donepezil. The actigraphy results indicate that the sum of all wake epochs within the sleep period, which reflects the degree of fragmented sleep, and the AAC decreased in the DLB patients after donepezil treatment. These results indicate that donepezil treatment reduced sleep disturbances in DLB patients.

Noninvasive prediction of shunt operation outcome in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a syndrome characterized by gait disturbance, cognitive deterioration and urinary incontinence in elderly individuals. These symptoms can be improved by shunt operation in some but not all patients. Therefore, discovering predictive factors for the surgical outcome is of great clinical importance. We used normalized power variance (NPV) of electroencephalography (EEG) waves, a sensitive measure of the instability of cortical electrical activity, and found significantly higher NPV in beta frequency band at the right fronto-temporo-occipital electrodes (Fp2, T4 and O2) in shunt responders compared to non-responders. By utilizing these differences, we were able to correctly identify responders and non-responders to shunt operation with a positive predictive value of 80% and a negative predictive value of 88%. Our findings indicate that NPV can be useful in noninvasively predicting the clinical outcome of shunt operation in patients with iNPH.

Cerebrospinal Fluid Biomarkers of Alzheimer’s Disease Correlate With Electroencephalography Parameters Assessed by Exact Low-Resolution Electromagnetic Tomography (eLORETA):

Recently, cerebrospinal fluid (CSF) biomarkers related to Alzheimer’s disease (AD) have garnered a lot of clinical attention. To explore neurophysiological traits of AD and parameters for its clinical diagnosis, we examined the association between CSF biomarkers and electroencephalography (EEG) parameters in 14 probable AD patients. Using exact low-resolution electromagnetic tomography (eLORETA), artifact-free 40-sesond EEG data were estimated with current source density (CSD) and lagged phase synchronization (LPS) as the EEG parameters. Correlations between CSF biomarkers and the EEG parameters were assessed. Patients with AD showed significant negative correlation between CSF beta-amyloid (Aβ)-42 concentration and the logarithms of CSD over the right temporal area in the theta band. Total tau concentration was negatively correlated with the LPS between the left frontal eye field and the right auditory area in the alpha-2 band in patients with AD. Our study results suggest that AD biomarkers, in particular CSF Aβ42 and total tau concentrations are associated with the EEG parameters CSD and LPS, respectively. Our results could yield more insights into the complicated pathology of AD.

Alpha event-related synchronization after eye closing differs in Alzheimer's disease and dementia with Lewy bodies: a magnetoencephalography study: Alpha ERS in AD and DLB: a MEG study

The electroencephalography (EEG) abnormalities found in patients with dementia with Lewy bodies (DLB) are conflicting. In this study, we used magnetoencephalography, which has higher spatial resolution than electroencephalography, to explore neurophysiological features of DLB that may aid in the differential diagnosis.