Feature Importance Analysis and Machine Learning for Alzheimer's Disease Early Detection: Feature Fusion of the Hippocampus, Entorhinal Cortex, and Standardized Uptake Value Ratio.

Introduction: Alzheimer's disease (AD) is a progressive neurological disorder characterized by mild memory loss and ranks as a leading cause of mortality in the USA, accounting for approximately 120,000 deaths per year. It is also the primary form of dementia. Early detection is critical for timely intervention as the neurodegenerative process often starts 15-20 years before cognitive symptoms manifest.

Long-term effects of mTBIs includes a higher dependency on visual inputs to control vertical posture.

This study investigated the hypothesis that individuals living with long-term effects of mild traumatic brain injury (mTBI) develop an increased dependency on visual inputs to control upright posture. To test this hypothesis, we quantified visuo-postural dependency indices (VPDIs) calculated for multiple postural behavioral markers extracted from the body's center of pressure coordinates signals. These signals were recorded during the execution of a quiet bipedal stance under and experimental conditions.

Are menstrual symptoms associated with central sensitization inventory? A cross-sectional study.

Background: Dysmenorrhoea is a prevalent pain condition that affects women of reproductive age, who are monthly exposed to this pain, usually until they reach adult age, or even after that, which can predispose them to Central Sensitization. The present study aimed to observe the association between menstrual characteristics and central sensitivity symptoms in women.

Methods: Cross-sectional study.

Visuo-postural dependency index (VPDI) in human postural control.

Background: Computerized stabilometry has been utilized to investigate the effect of vision on the neuromechanisms of human postural control. However, this approach lacks operational methods to quantify visual dependency during upright stance. This study had three goals: (1) To introduce the concept of visuo-postural dependency indices (VPDI) representing balance sway characteristics in multiple analytical domains (spatial, temporal, frequency, and structural), (2) To investigate the age and gender effects on VPDIs, and (3) To investigate the degree of relationships between VPDI and both subjective visual vertical and horizontal perception (SVV and SVH, respectively).

Postural Behavior in Medicated Parkinson Disease Patients: A Preliminary Study Searching for Indicators to Track Progress.

Purpose: The establishment of early diagnostic methods for Parkinson disease (PD) is one of the key features to clinically control the rate of PD progression. This study aimed to give a first step toward recognizing the efficacy of multiple postural indices of balance control in differentiating medicated PD patients from health participants.

Methods: Nine individuals with PD (Hoehn and Yahr Stage up to 2), 9 staged 2.

The effects of aging on the distribution and strength of correlated neural inputs to postural muscles during unperturbed bipedal stance.

The present study investigated the effects of aging on the distribution of common descending neural drives to main postural muscles acting on the ankle, knee, hip, and lower trunk. The presence, distribution, and strength of these drives were assessed using intermuscular coherence estimations at a low-frequency band (0-55 Hz). Ten healthy older adults (68.

Upright balance control strategies during pregnancy.

Background: Morphological and physiological changes during pregnancy are considered to interfere with the mechanisms of postural control and potentially increase the risk of falling. A clear understanding of these mechanisms is important to improve pre-natal care and reduce the fall risk in this population.

Objectives: This study focused on investigating how pregnancy affects postural control in each trimester of pregnancy by analyzing pelvic inclination and body sway behavior.

Author Correction: Long-term effects of mild traumatic brain injuries to oculomotor tracking performances and reaction times to simple environmental stimuli.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Long-term effects of mild traumatic brain injuries to oculomotor tracking performances and reaction times to simple environmental stimuli.

Understanding the long-term effects of concussive events remains a challenge for the development of modern medical practices and the prevention of recurrent traumas. In this study, we utilized indices of oculomotor performance and the ability to react to simple environmental stimuli to assess the long-term motor effects of traumatic brain injury in its mildest form (mTBI). We performed analysis of eye movement accuracy, investigated the presence of abnormal eye movements, and quantified time to react to simple environmental stimuli on long-term mTBI survivors.

The effects of early stages of aging on postural sway: A multiple domain balance assessment using a force platform.

Technical advancements in instrumentation and analytical methods have improved the ability of assessing balance control. This study investigated the effects of early stages of aging on postural sway using traditional and contemporary postural indices from different domains. Eleven healthy young adults and fourteen healthy non-faller older adults performed two postural tasks: (a) functional limits of stability and (b) unperturbed bipedal stance for 120s.

The use of intermuscular coherence analysis as a novel approach to detect age-related changes on postural muscle synergy.

The overall goal of this study was to investigate potential adaptations brought about by the natural processes of aging on the coordination of postural muscles. Considering the progressive and non-homogeneous deterioration of sensorimotor and neuromuscular systems as the individual grows older, it was hypothesized that aging is associated with a reorganization of synergistic mechanisms controlling postural muscles. Therefore, the presence, distribution, and strength of correlated neural inputs to three posterior postural muscles were measured by intermuscular coherence estimations at a low frequency band (0-55Hz).

The effects of mild traumatic brain injury on postural control.

Primary Objective: The purpose of this study was to investigate the effects of mild traumatic brain injury (mTBI) on multiple postural indices that characterize body sway behaviour.

Methods And Procedures: The body's centre of pressure (COP) displacement was recorded from 11 individuals with a history of mTBI (29.4 ± 6.

Corticomotor excitability changes during mirrored or asynergistic wrist movements.

The current study used transcranial magnetic stimulation (TMS) of the right primary motor cortex (M1) during bimanual contractions to examine facilitatory and inhibitory influences on the contralateral, target extensor carpi radialis muscle (ECR) during changes in the task demands of the ipsilateral (task) ECR. The bimanual contractions were either mirrored (isometric wrist extension bilaterally) or more difficult asynergistic (asymmetric [wrist extension paired with wrist radial deviation]) contractions. TMS-induced motor evoked potentials (MEPs) and cortical silent periods (CSPs) were recorded during the execution of visually guided ramp and hold tasks.

The influence of visual information on multi-muscle control during quiet stance: a spectral analysis approach.

Standing upright requires the coordination of neural drives to a large set of muscles involved in controlling human bipedal stance (i.e., postural muscles).

Multi-muscle control during bipedal stance: an EMG-EMG analysis approach.

Posture and postural reactions to mechanical perturbations require the harmonic modulation of the activity of multiple muscles. This precision can become suboptimal in the presence of neuromuscular disorders and result in higher fall risk and associated levels of comorbidity. This study was designed to investigate neurophysiological principles related to the generation and distribution of inputs to skeletal muscles previously recognized as a synergistic group.

Influence of fatigue on hand muscle coordination and EMG-EMG coherence during three-digit grasping.

Fingertip force control requires fine coordination of multiple hand muscles within and across the digits. While the modulation of neural drive to hand muscles as a function of force has been extensively studied, much less is known about the effects of fatigue on the coordination of simultaneously active hand muscles. We asked eight subjects to perform a fatiguing contraction by gripping a manipulandum with thumb, index, and middle fingers while matching an isometric target force (40% maximal voluntary force) for as long as possible.

Force-independent distribution of correlated neural inputs to hand muscles during three-digit grasping.

The ability to modulate digit forces during grasping relies on the coordination of multiple hand muscles. Because many muscles innervate each digit, the CNS can potentially choose from a large number of muscle coordination patterns to generate a given digit force. Studies of single-digit force production tasks have revealed that the electromyographic (EMG) activity scales uniformly across all muscles as a function of digit force.

Kinematic synergies during saccades involving whole-body rotation: a study based on the uncontrolled manifold hypothesis.

We used the framework of the uncontrolled manifold hypothesis to study the coordination of body segments and eye movements in standing persons during the task of shifting the gaze to a target positioned behind the body. The task was performed at a comfortable speed and fast. Multi-segment and head-eye synergies were quantified as co-varied changes in elemental variables (body segment rotations and eye rotation) that stabilized (reduced the across trials variability) of head rotation in space and gaze trajectory.

Multi-muscle synergies in a dual postural task: evidence for the principle of superposition.

We used the framework of the uncontrolled manifold hypothesis to quantify multi-muscle synergies stabilizing the moment of force about the frontal axis (M(Y)) and the shear force in the anterior-posterior direction (F(X)) during voluntary body sway performed by standing subjects. We tested a hypothesis whether the controller could stabilize both M(Y) and F(X) at the same time when the task and the visual feedback was provided only on one of the variables (M(Y)). Healthy young subjects performed voluntary body sway in the anterior-posterior direction while different loads were attached at the ankle level producing horizontal forces acting forward or backwards.

Postural control during upper body locomotor-like movements: similar synergies based on dissimilar muscle modes.

We studied the organization of leg and trunk muscles into groups (M-modes) and co-variation of M-mode involvement (M-mode synergies) during whole-body tasks associated with large variations of the moment of force about the vertical body axis. Our major questions were: (1) can muscle activation patterns during such tasks be described with a few M-modes common across tasks and subjects? (2) do these modes form the basis for synergies stabilizing M(z) time pattern? (3) will this organization differ between an explicit body-rotation task and a task associated with locomotor-like alternating arm movements? Healthy subjects stood barefoot on the force platform and performed two motor tasks while paced by the metronome at 0.7, 1.

Flexible muscle modes and synergies in challenging whole-body tasks.

We used the idea of hierarchical control to study multi-muscle synergies during a whole-body sway task performed by a standing person. Within this view, at the lower level of the hierarchy, muscles are united into groups (M-modes). At the higher level, gains at the M-modes are co-varied by the controller in a task-specific way to ensure low variability of important physical variables.

Is voluntary control of natural postural sway possible?

The authors explored whether standing human participants could voluntarily decrease the amplitude of their natural postural sway when presented with explicit visual feedback and a target. Participants (N = 9) stood quietly, without any feedback and with feedback on the center of pressure coordinate or the head orientation. They were unable to decrease sway amplitude when presented with visual feedback and a target.

Postural preparation to making a step: is there a 'motor program' for postural preparation?

We tested the hypothesis that a sequence of mechanical events occurs preceding a step that scales in time and magnitude as a whole in a task-specific manner, and is a reflection of a "motor program." Young subjects made a step under three speed instructions and four tasks: stepping straight ahead, down a stair, up a stair, and over an obstacle. Larger center-of-pressure (COP) and force adjustments in the anterior-posterior direction and smaller COP and force adjustments in the mediolateral direction were seen during stepping forward and down a stair, as compared with the tasks of stepping up a stair and over an obstacle.

Anticipatory control of head posture.

Objective: We tested a hypothesis on two patterns of anticipatory postural adjustments (APAs) in neck muscles, reciprocal and co-activation, that may be used in a task-specific way. We also explored possible relation of APAs in leg and trunk muscles to head stabilization.

Methods: Load perturbations (loading and unloading) were applied to the head, trunk, and head and trunk simultaneously using similar hand actions by standing persons.