Catarina Costa Boffino

Fear of heights: cognitive performance and postural control.

IntroductionFear of heights, or acrophobia, is one of the most frequent subtypes of specific phobia frequently associated to depression and other anxiety disorders. Previous evidence suggests a correlation between acrophobia and abnormalities in balance control, particularly involving the use of visual information to keep postural stability. This study investigates the hypotheses that (1) abnormalities in balance control are more frequent in individuals with acrophobia even when not exposed to heights, that (2) acrophobic symptoms are associated to abnormalities in visual perception of movement; and that (3) individuals with acrophobia are more sensitive to balance-cognition interactions.MethodThirty-one individuals with specific phobia of heights and thirty one non-phobic controls were compared using dynamic posturography and a manual tracking task.ResultsAcrophobics had poorer performance in both tasks, especially when carried out simultaneously. Previously described interference between posture control and cognitive activity seems to play a major role in these individuals.DiscussionThe presence of physiologic abnormalities is compatible with the hypothesis of a non-associative acquisition of fear of heights, i.e., not associated to previous traumatic events or other learning experiences. Clinically, this preliminary study corroborates the hypothesis that vestibular physical therapy can be particularly useful in treating individuals with fear of heights.

Balance disturbances in asthmatic patients.

Objective. The aim of this study was to investigate balance control in asthmatic patients. Methods. Thirty subjects with controlled persistent asthma were compared with 30 non-asthmatic subjects who were matched by age and sex. Individuals who had received psychiatric treatment, demonstrated chronic musculoskeletal pain, had limited joint movements, or showed vestibular or other equilibrium disorders were excluded from both the groups to avoid biomechanical bias in the dynamic posturography. Balance control was evaluated with the subject standing still on a force platform under four different sensory test conditions. These conditions combined the subject’s eyes being opened or closed with a fixed or mobile force platform. A mobile platform provides a somatosensory perturbation, and when associated with the eyes closed condition, only vestibular information is available to moderate balance control. Sensory manipulation provides a more sensitive condition to differentiate postural control between populations or pathologies. Data were sampled at 100 Hz in three 20-second trials and four postural conditions were assessed. The center of pressure (CoP) displacement values were used to calculate area and velocity in the medial–lateral and forward–backward directions. A two-factor analysis of variance with repeated measurements was applied to the data. Results. In comparison to the control group, the asthma group demonstrated a greater area of CoP displacement in conditions using the mobile force platform (with eyes opened or closed) and a higher velocity in forward–backward direction on the mobile platform with the eyes closed. Conclusion. Asthmatic individuals presented a greater area for the CoP displacement under somatosensory perturbations and a higher velocity in the forward–backward direction when vestibular information only was made available. Our data suggest that balance needs to be evaluated in asthmatic patients.

An fMRI-compatible force measurement system for the evaluation of the neural correlates of step initiation

Knowledge of brain correlates of postural control is limited by the technical difficulties in performing controlled experiments with currently available neuroimaging methods. Here we present a system that allows the measurement of anticipatory postural adjustment of human legs to be synchronized with the acquisition of functional magnetic resonance imaging data. The device is composed of Magnetic Resonance Imaging (MRI) compatible force sensors able to measure the level of force applied by both feet. We tested the device in a group of healthy young subjects and a group of elderly subjects with Parkinson’s disease using an event-related functional MRI (fMRI) experiment design. In both groups the postural behavior inside the magnetic resonance was correlated to the behavior during gait initiation outside the scanner. The system did not produce noticeable imaging artifacts in the data. Healthy young people showed brain activation patterns coherent with movement planning. Parkinson’s disease patients demonstrated an altered pattern of activation within the motor circuitry. We concluded that this force measurement system is able to index both normal and abnormal preparation for gait initiation within an fMRI experiment.

Development of postural control and maturation of sensory systems in children of different ages a cross-sectional study

Highlights • This study has promotes a better understanding on the evolution of stability, functional maturation of sensorial integration and postural adjustments in children.• This study has combined biomechanical and motor control concepts, discussing the parameters separately stability and postural adjustments.• This study indicated Postural stability and adjustments were associated with age and were influenced by sensory manipulation and seven-year-olds seem to go through a period of differentiated singularity in postural control.