Resource management in IP-based radio access networks

IP is being considered to be used in the Radio Access Network (RAN) of UMTS. It is of paramount importance to be able to provide good QoS guarantees to real time services in such an IP-based RAN. QoS in IP networks is most efficiently provided with Differentiated services (Diffserv). However, currently Diffserv mainly specifies Per Hop Behaviors (PHB). Proper mechanisms for admission control and resource reservation have not yet been defined. A new resource management concept in the IP-based RAN is needed to offer QoS guarantees to real time services. We investigate the current Diffserv mechanisms and contribute to development of a new resource management protocol. We focus on the load control algorithm [9], which is an attempt to solve the problem of admission control and resource reservation in IP-based networks. In this document we present some load control issues and propose to enhance the load control protocol with the Measurement Based Admission Control (MBAC) concept. With this enhancement the traffic load in the IP-based RAN can be estimated, since the ingress router in the network path can be notified by marking packets with the resource state information. With this knowledge, the ingress router can perform admission control to keep the IP-based RAN stable with a high utilization even in overload situations

Gait variability at fast-pace walking speed: A biomarker of mild cognitive impairment?

The interpretation of the increase in stride-to-stride variability of stride time (STV) regarding the evolution of cognitive deficits across the dementia spectrum is matter of debate.The aim of this study was to compare STV at usual and fast-pace walking speeds of MCI patients with that of cognitively healthy individuals (CHI) and Alzheimer\u27s disease (AD) patients with mild dementia, while considering the effects of potential confounders. STV while walking at usual and fast-pace walking speeds was recorded with the GAITRiteA (R) system from 116 older adults (mean age 75.6 +/- 6.5 years; 55.2% female) divided into 3 groups according to their cognitive status (44 CHI, 39 MCI patients and 33 AD patients with mild dementia). The full adjusted multiple linear regression models showed that high STV was associated with slow gait speed at usual-pace walking speed (P=0.002) and with the MCI status at fast-pace walking speed (P=0.015). High STV at fast-pace walking speed was a specific gait disturbance of MCI patients in the sample of studied participants, and thus could be used in the future as a specific biomarker of MCI patients

Derivation and validation of a Short Form of the Mini-Mental State Examination for the screening of dementia in older adults with a memory complaint

BACKGROUND AND PURPOSE: To validate a Short Form of the Mini-Mental State Examination (SMMSE) as a screening test for dementia in older ambulatory individuals followed in a memory clinic for a memory complaint. METHODS: A total of 202 cognitively healthy individuals, 100 individuals with a mild cognitive impairment and 304 demented individuals sent for a memory complaint by their primary care physician to a memory clinic were prospectively included in this cross-sectional study. They were randomized into derivation (n = 303) and validation (n = 303) groups. The SMMSE score was built from six memory items of MMSE, with a score ranging from 0 to 6 (i.e. best performance). RESULTS: The receiver operating characteristic curve showed an area under the curve of 0.98 for the derivation group and 0.97 for the validation group without differences between curves (P = 0.254). The cut-off between the sensitivity and the specificity of the SMMSE score for clinically diagnosed dementia wa

Vitamin D insufficiency and mild cognitive impairment: cross-sectional association

BACKGROUND: Low serum 25-hydroxyvitamin D (25OHD) concentrations have been associated with dementia. The association with mild cognitive impairment (MCI) has not yet been explored. Our aim was to examine the association between vitamin D status and MCI status amongst older community-dwellers with subjective memory complaint.METHODS: Ninety-five non-demented Caucasian community-dwellers with subjective memory complaint (mean, 71.16.4years; 54.7% women) included in the Gait and Alzheimer Interaction Tracking (GAIT) study were categorized into two groups according to Winblad et al. consensus criteria [i.e., subjects with MCI or cognitively healthy individuals (CHI)]. Serum 25OHD concentration was divided into quartiles, the fourth quartile corresponding to the highest 25OHD concentration. The cross-sectional associations between 25OHD concentrations and MCI were modeled using logistic regressions. Age, gender, body mass index, number of comorbidities, education level, Mini-Mental State Examination score, Frontal Assessment Battery score, Geriatric Depression Scale score, creatinine clearance, and season tested were considered as potential confounders. RESULTS: Compared to CHI, patients with MCI (n=43; mean, 71.45.6years; 34.9% women) had lower mean serum 25OHD concentrations (P=0.006) and belonged more often to the lower quartiles compared to the highest quartile (P=0.03). Increased serum 25OHD concentration was associated with a lower risk of MCI [adjusted odds ratio (OR)=0.96, P=0.002]. Accordingly, lower quartiles of 25OHD were positively associated with MCI whilst using the highest quartile as reference (adjusted OR=25.46, P=0.002 for the first quartile; adjusted OR=6.89, P=0.03 for the second quartile; and adjusted OR=10.29, P=0.02 for the third quartile). CONCLUSIONS: Low 25OHD concentrations were associated with MCI status in older non-demented community-dwellers with subjective memory complaint

Motor phenotype of decline in cognitive performance among community-dwellers without dementia: Population-based study and meta-analysis

Background: Decline in cognitive performance is associated with gait deterioration. Our objectives were: 1) to determine, from an original study in older community-dwellers without diagnosis of dementia, which gait parameters, among slower gait speed, higher stride time variability (STV) and Timed Up & Go test (TUG) delta time, were most strongly associated with lower performance in two cognitive domains (i.e., episodic memory and executive function); and 2) to quantitatively synthesize, with a systematic review and meta-analysis, the association between gait performance and cognitive decline (i.e., mild cognitive impairment (MCI) and dementia). Methods: Based on a cross-sectional design, 934 older community-dwellers without dementia (mean6standard deviation, 70.3 64.9years; 52.1% female) were recruited. A score at 5 on the Short Mini-Mental State Examination defined low episodic memory performance. Low executive performance was defined by clock-drawing test errors. STV and gait speed were measured using GAITRite system. TUG delta time was calculated as the difference between the times needed to perform and to imagine the TUG. Then, a systematic Medline search was conducted in November 2013 using the Medical Subject Heading terms "Delirium," "Dementia," "Amnestic," "Cognitive disorders" combined with "Gait" OR "Gait disorders, Neurologic" and "Variability." Findings: A total of 294 (31.5%) participants presented decline in cognitive performance. Higher STV, higher TUG delta time, and slower gait speed were associated with decline in episodic memory and executive performances (all P-values <0.001). The highest magnitude of association was found for higher STV (effect size = -0.74 [95% Confidence Interval (CI): -1.05;- 0.43], among participants combining of decline in episodic memory and in executive performances). Meta-analysis underscored that higher STV represented a gait biomarker in patients with MCI (effect size = 0.48 [95% CI: 0.30;0.65]) and dementia (effect size = 1.06 [95% CI: 0.40;1.72]). Conclusion: Higher STV appears to be a motor phenotype of cognitive decline. © 2014 Beauchet et al

Resource management in Diffserv measurement-based admission control PHR

The purpose of this draft is to present the Resource Management in Diffserv (RMD) Measurement-Based Admission Control (RIMA) Per Hop Reservation (PHR) protocol. The RIMA PHR protocol is used on a per-hop basis in a Differentiated Services (Diffserv) domain and extends the Diffserv Per Hop Behavior (PHB) with Measurement-based Admission Control features