The Independent Channel (IC) model is a commonly used linear balance control model in the frequency domain to analyze human balance control using system identification and parameter estimation. The IC model is a rudimentary and noise-free description of balance behavior in the frequency domain, where a stable model representation is not guaranteed. In this study, we conducted firstly time-domai...

Upright gait is a peculiar characteristic of humans that requires the ability to manage upper body dynamic balance while walking, despite the perturbations that are generated by movements of the lower limbs. Most of the studies on upright gait stability have compared young adults and the elderly to determine the effects of aging. In other studies, the comparison was between healthy subjects and...

OBJECTIVE To investigate how physical activity changes over the first 6 months after stroke, and how activity is related to function. DESIGN A longitudinal study with an initial assessment within 14 days after stroke (in hospital) and follow-up assessments 1, 3 and 6 months later (in-patient rehabilitation or at home). SUBJECTS Patients with acute stroke. METHODS An accelerometer with a s...

OBJECTIVE The objectives of the present study were to assess the effects of dopaminergic drugs on the postural balance of Parkinson disease (PD) patients and to ascertain whether their sway is greater along the mediolateral or the anteroposterior axis. DESIGN Twenty-two patients awaiting operations for implantation of a deep brain stimulator at the neurology service of Hospital das Clínicas, ...

Balance is defined as a state of equilibrium or parity characterized by cancellation of all forces by equal opposing factors. This is the act of maintaining an upright posture (static balance) or in locomotion (dynamic balance or gait). This system depends on vestibular function, vision, and proprioception to maintain posture, to navigate in one's surroundings, to coordinate motion of body part...

Human standing balance is a complex of systems, like the muscles, nervous system and sensory systems, interacting with each other in a closed loop to maintain upright stance. With age, disease and medication use these systems deteriorate, which could result in impaired balance. In this paper, it is demonstrated that multi-input-multi-output closed loop system identification techniques (MIMO-CLS...

When a person standing upright raises an arm on cue, muscles of the left and right sides of the body exhibit changes prior to and specific to the responding arm. We had standing participants perform a visual lexical decision task ("is this letter string a word?"), responding yes by raising one arm and no by raising the other arm. We recorded onset of the arm movement and onset of electromyograp...

Maintenance of upright posture involves complex neuromotor processes that include control of thoracic and abdominal pressures. Control of airflow by glottal structures is a primary determinant of thoracic pressure and may have a role in control of postural stability. This study aimed to investigate the effect of modulation of airway control on upright postural stability during postural perturba...