Neutrophil activation in Alzheimer's disease and mild cognitive impairment: A systematic review and meta-analysis of protein markers in blood and cerebrospinal fluid.

Inflammation is involved in the pathophysiology of Alzheimer's disease (AD), with multiple inflammatory processes implicated in its risk and progression. This review included original peer-reviewed studies measuring the cerebrospinal fluid or peripheral blood concentrations of protein markers specifically related to neutrophil activity in healthy controls (HC) and in patients with AD or mild cognitive impairment (MCI). A total of 35 studies (NHC = 3095, NAD = 2596, NMCI = 1203) were included. Random-effects meta-analyses were used to estimate between-groups standardized mean differences (SMD) and 95 % confidence intervals. In blood, concentrations of myeloperoxidase (MPO; NAD/NHC = 271/209, SMD = 0.41 [0.20, 0.62]; I2 = 15.7 %) and neutrophil gelatinase associated lipocalin (NGAL; NAD/NHC = 273/185, SMD = 0.30 [0.11, 0.49]; I2 < 0.005 %) were significantly higher in AD relative to HC. Peripheral blood concentrations of NGAL were also higher in MCI compared to HC (NMCI/NHC = 489/145, SMD = 0.39 [0.11, 0.67]; I2 = 38.6 %). None of the protein markers exhibited a significant difference between HC, MCI, or AD groups in the cerebrospinal fluid. The evidence suggests that peripheral neutrophil activation, as indicated by blood concentrations of NGAL and MPO, may be a pathological feature of cognitive impairment due to AD, evident at stages of MCI and AD dementia.

Shoulder physiotherapy exercise recognition: machine learning the inertial signals from a smartwatch.

OBJECTIVE: Participation in a physical therapy program is considered one of the greatest predictors of successful conservative management of common shoulder disorders. However, adherence to these protocols is often poor and typically worse for unsupervised home exercise programs. Currently, there are limited tools available for objective measurement of adherence in the home setting. The goal of this study was to develop and evaluate the potential for performing home shoulder physiotherapy monitoring using a commercial smartwatch. APPROACH: Twenty healthy adult subjects with no prior shoulder disorders performed seven exercises from an evidence-based rotator cuff physiotherapy protocol, while 6-axis inertial sensor data was collected from the active extremity. Within an activity recognition chain (ARC) framework, four supervised learning algorithms were trained and optimized to classify the exercises: k-nearest neighbor (k-NN), random forest (RF), support vector machine classifier (SVC), and a convolutional recurrent neural network (CRNN). Algorithm performance was evaluated using 5-fold cross-validation stratified first temporally and then by subject. MAIN RESULTS: Categorical classification accuracy was above 94% for all algorithms on the temporally stratified cross validation, with the best performance achieved by the CRNN algorithm (99.4%). The subject stratified cross validation, which evaluated classifier performance on unseen subjects, yielded lower accuracies scores again with CRNN performing best (88.9%). SIGNIFICANCE: This proof of concept study demonstrates the technical feasibility of a smartwatch device and supervised machine learning approach to more easily monitor and assess the at-home adherence of shoulder physiotherapy exercise protocols.

Electrical stimulation of acupuncture points and blood pressure responses to postural changes: a pilot study.

BACKGROUND: Application of transcutaneous electrical stimulation over acupuncture points (Acu-TENS) facilitates heart rate recovery after exercise and restores hemodynamic stability after open heart surgery. The role of Acu-TENS on cardiovascular parameters in response to postural changes has not been reported. OBJECTIVE: To investigate (1) the effect of Acu-TENS on blood pressure responses to -10º head-down postural change and (2) whether such effects were associated with modulation by the autonomic nervous system. METHOD: Sixteen healthy volunteers, mean age 22.8 (SD, 3.1) years, were subjected to a -10º head-down tilt from the supine position on 3 separate occasions and received in random order the following 3 intervention protocols for 40 minutes before the postural change: Acu-TENS (over bilateral acupuncture points, PC6), sham-TENS (TENS applied to the skin over the patellae), and control (no electrical output from the TENS device applied at PC6). Mean arterial pressure, large artery elasticity index, cardiac output, and heart rate were recorded and compared at different stimulation protocols in the supine and -10º head-down tilt positions. Spectral analysis of heart rate variability was used to determine any modulation by the autonomic nervous system. RESULTS: Change in large artery elasticity index was observed only in the Acu-TENS group (P < .05) and mean arterial pressure appeared most stable during Acu-TENS. Autonomic nervous system modulation was not apparent with spectral analysis, irrespective of intervention. Sympathetic activity predominated in all positions. CONCLUSION: Acu-TENS seems to reduce blood pressure changes with -10º head-down tilt with concomitant changes in arterial vessel tone.