Postural Reflex

This study examined the task-dependency of sensory inputs on motoneuron excitability by comparing the inhibitory post-synaptic potential (IPSP) evoked by stimulation of the sural nerve between a standing postural task (Free Standing) and a comparable voluntary isometric contraction performed in supine (Lying Supine). We hypothesized that there would be a smaller IPSP in standing than in supine, based on the task dependence of the ankle plantarflexor activity to the standing task. Ten healthy participants participated in a total of 15 experiments...

The most frequent cause of syncope in young athletes is noncardiac etiology. The mechanism of noncardiac syncope (NCS) in young athletes is neurally-mediated (reflex). NCS in athletes usually occurs either as orthostasis-induced, due to a gravity-mediated reduced venous return to the heart, or in the context of exercise. Exercise-related NCS typically occurs after the cessation of an exercise bout, while syncope occurring during exercise is highly indicative of the existence of a cardiac disorder. Postexercise NCS appears to result from hypotension due to impaired postexercise vasoconstriction, as well as from hypocapnia...

Stroke is one of the most common causes of death worldwide and also responsible for permanent disability. Ischemic stroke has been found to affect 80% of stroke patients. Recombinant tissue plasminogen activator (rtPA) is the widely used drug for the ischemic stroke with narrow therapeutic window. Indole-3-carbinol (I3C) is a natural compound obtained from brassica species having antithrombotic activity. Middle cerebral artery occlusion (MCAO) model was used followed by reperfusion after 2 h of ischemia for the evaluation of the I3C against ischemic stroke...

To maintain balance during dynamic locomotion, the effects of proprioceptive sensory feedback control (e.g. reflexive control) should not be ignored because of its simple sensation and fast reaction time. Scientists have identified the pathways of reflexes; however, it is difficult to investigate their effects during locomotion because locomotion is controlled by a complex neural system and current technology does not allow us to change the control pathways in living humans. To understand these effects, we construct a musculoskeletal bipedal robot, which has similar body structure and dynamics to those of a human...

Late preterm infants (34-0/7 to 36-6/7 weeks" gestation) account for 10-20% of NICU admissions and are at increased risk for morbidity and mortality. Although they are prone to developmental delays, reports on neurological outcome during the first 2 years of life are scarce. The aim of the study was to assess neurological/neuromotor outcome in high risk late preterm infants at 6 and 12 months corrected age and the change in neurological scores over time, and to identify factors associated with the neurological outcome...

Speech-Language Pathologists (SLP) play an integral role in evaluating and treating pediatric patients with dysphagia related to aerodigestive disorders. Non-supportive anatomy, cardio-respiratory and medical status, state control, neurologic functioning, postural stability and control, gastrointestinal functioning, hunger and satiation, developmental abilities, oral-motor skills, oral/pharyngeal reflexes, airway protection and secretion management can create barriers to successful oral feeding. Swallowing is broken down into four phases and difficulties can occur during any phase or in combination with another phase of swallowing...

BACKGROUND: The angle of trunk rotation (ATR) is a measurement that allows an objective assessment of a growing child's spine. Early detection of trunk rotation prevents the progression of scoliosis. One of the factors that predispose children to the formation of faulty posture may be primitive reflexes, which should be integrated in the central nervous system (CNS) by the age of one year. If retained, primitive reflexes affect children's physical development as well as their development at school...

The Dizziness Handicap Inventory (DHI) is believed to quantitate the handicap related to the presence or severity of underlying vestibular dysfunction. However, patients with chronic vestibular diseases may manifest various degrees of behavioural and physiological adaptation resulting in variances of the DHI. Our primary study objective is to evaluate the correlation between the DHI and measurable vestibular parameters. Secondarily, we compared DHI among different vestibular disorders (central, peripheral and functional), and different types of anatomic deficits (semicircular canal vs otolithic)...

OBJECTIVE: To evaluate dexmedetomidine, midazolam and dexmedetomidine-midazolam for sedation and antinociception in tegus. STUDY DESIGN: Prospective, crossover, randomized, blinded study. ANIMALS: Six healthy tegus (Salvator merianae) weighing 1.6±0.3 kg. METHODS: Tegus were administered intramuscularly saline (0.5 mL; CON), dexmedetomidine (0.2 mg kg-1 ; DX), midazolam (1 mg kg-1 ; MZ) and dexmedetomidine-midazolam (same doses; DM)...

OBJECTIVE: Considering the altered multisensory signal compensation during senescence, the aim of the present study was to evaluate the integration rearrangements in unilateral vestibular hypofunction (UVH) during age-related cognitive decline. STUDY DESIGN: Cross-sectional study. SETTING: Longitudinal cohort study unit and of University tertiary referral center. PATIENTS: Older UVH individuals ≥ 55 years with Mild Cognitive Impairment (MCI) or Alzheimer Disease (AD) and matched UVH control group with age-appropriate cognitive function...

OBJECTIVE: Craniovertebral junctional anomalies constitute a technical challenge. Surgical opening of atlantoaxial joint region is a complex procedure especially in patients with nuchal deformity like basilar invagination. This region has actually very complicated anatomical and functional characteristics, including multiple joints providing extension, flexion, and wide rotation. In fact, it is also a bottleneck region where bones, neural structures, and blood vessels are located. Stabilization surgery regarding this region should consider the fact that the area exposes excessive and life-long stress due to complex movements and human posture...

OBJECTIVES: To examine the mechanism underlying previously reported ameliorating effects of noisy galvanic vestibular stimulation (GVS) on balance performance in patients with bilateral vestibulopathy (BVP) and determine those patients (incomplete versus complete vestibular loss) that might benefit from this intervention. METHODS: Vestibulospinal reflex thresholds were determined in 12 patients with BVP [2 with complete loss (cBVP) and 10 with residual function (rBVP)]...

Developmental coordination disorder (DCD) is a common motor disorder affecting balance performance. However, few studies have investigated reactive balance performance and the underlying mechanisms in children with DCD. This study aimed to compare the reactive balance performance, lower limb muscle reflex contraction latency and attention level in response to unpredictable balance perturbations between 100 typically developing children and 120 children with DCD (with and without comorbid autism spectrum disorder) aged 6-9 years...

Dystonia is a collection of symptoms with involuntary muscle activation causing hypertonia, hyperkinetic movements, and overflow. In children, dystonia can have numerous etiologies with varying neuroanatomic distribution. The semiology of dystonia can be explained by gain-of-function failure of a feedback controller that is responsible for stabilizing posture and movement. Because postural control is maintained by a widely distributed network, many different anatomic regions may be responsible for symptoms of dystonia, although all features of dystonia can be explained by uncontrolled activation or hypersensitivity of motor cortical regions that can cause increased reflex gain, inserted postures, or sensitivity to irrelevant sensory variables...

Individuals with intellectual disabilities (ID) (50 < IQ < 79) show impaired motor and postural control, these impairments are highly related to falls and injuries. Recent studies demonstrated these impairments are related with fine and gross motor development, which are more strongly associated with cognition, and consequently language for individuals with ID than for without ID. Despite these studies, little is known about the structure and functioning of this population's spinal cord, which is highly involved in postural control...

Fall prevention has an indispensable role in enhancing life expectancy and quality of life among older adults. The first step to prevent falls is to devise reliable methods to identify individuals at high fall risk. The purpose of the current study was to assess alterations in local postural muscle and central sensory balance control mechanisms due to low-frequency externally applied vibration among elders at high fall risk, in comparison with healthy controls, as a potential tool for assessing fall risk. Three groups of participants were recruited: healthy young (n = 10; age = 23 ± 2 years), healthy elders (n = 10; age = 73 ± 3 years), and elders at high fall risk (n = 10; age = 84 ± 9 years)...

PURPOSE: Lateral trunk flexion is often observed in patients with Parkinson disease (PD) and causes poor quality of life. Asymmetrical function of the basal ganglia is believed to be the main cause of lateral trunk flexion, and dysfunction of the basal ganglia facilitates the blink reflex by disinhibiting the spinal trigeminal nucleus. Our aim was to investigate whether a disinhibited blink reflex recovery curve (BRrc) was associated with lateral trunk flexion in PD patients. METHODS: We enrolled 21 PD patients, including 11 with marked lateral trunk flexion (F-PD) and 10 with normal posture (N-PD), and 10 normal controls...

Motor control and body representation in the central nervous system (CNS) as well as musculoskeletal architecture and physiology are shaped during development by sensorimotor experience and feedback, but the emergence of locomotor disorders during maturation and their persistence over time remain a matter of debate in the absence of brain damage. By using transient immobilization of the hind limbs, we investigated the enduring impact of postnatal sensorimotor restriction (SMR) on gait and posture on treadmill, age-related changes in locomotion, musculoskeletal histopathology and Hoffmann reflex in adult rats without brain damage...

Objectives: To describe the motor pattern of cataplexy and to determine its phenomenological differences from pseudocataplexy in the differential diagnosis of episodic falls. Methods: We selected 30 video recorded cataplexy and 21 pseudocataplexy attacks in 17 and 10 patients evaluated for suspected narcolepsy and with final diagnosis of narcolepsy type 1 and conversion disorder respectively, together with self-reported attacks features, and asked expert neurologists to blindly evaluate the motor features of the attacks...

We studied the response to axial taps (mini-perturbations) of a group of 13 healthy older subjects (mean age 63 ± 12 years, 7 females, 6 males), 12 of whom were also studied using larger applied (macro-) perturbations requiring active postural responses. The mini-perturbation consisted of a brief impulsive force produced by a mini-shaker applied to the trunk at the level of the shoulders and anteriorly at the upper sternum which was perceived as a tap. Acceleration, force platform, and EMG measurements were made...