Balance in Blind Subjects: Cane and Fingertip Touch Induce Similar Extent and Promptness of Stance Stabilization.

Subjects with low vision often use a cane when standing and walking autonomously in everyday life. One aim of this study was to assess differences in the body stabilizing effect produced by the contact of the cane with the ground or by the fingertip touch of a firm surface. Another aim was to estimate the promptness of balance stabilization (or destabilization) on adding (or withdrawing) the haptic input from cane or fingertip. Twelve blind subjects and two subjects with severe visual impairment participated in two experimental protocols while maintaining the tandem Romberg posture on a force platform. In one protocol, subjects lowered the cane to a second platform on the ground and lifted it in sequence at their own pace. In the other protocol, they touched an instrumented pad with the index finger and withdrew the finger from the pad in sequence. In both protocols, subjects were asked to exert a force not granting mechanical stabilization. Under steady-state condition, the finger touch or the contact of the cane with the ground significantly reduced (to ∼78% and ∼86%, respectively) the amplitude of medio-lateral oscillation of the centre of foot pressure (CoP). Oscillation then increased when haptic information was removed. The delay to the change in body oscillation after the haptic shift was longer for addition than withdrawal of the haptic information (∼1.4 s and ∼0.7 s, respectively; p < 0.001), but was not different between the two haptic conditions (finger and cane). Similar stabilizing effects of input from cane on the ground and from fingertip touch, and similar latencies to integrate haptic cue from both sources, suggest that the process of integration of the input for balance control is initiated by the haptic stimulus at the interface cane-hand. Use of a tool is as helpful as the fingertip input, and does not produce different stabilization. Further, the latencies to haptic cue integration (from fingertip or cane) are similar to those previously found in a group of sighted subjects, suggesting that integration delays for automatic balance stabilization are not modified by visual impairment. Haptic input from a tool is easily exploited by the neural circuits subserving automatic balance stabilization in blind people, and its use should be enforced by sensory-enhancing devices and appropriate training.

Exploring Patient Awareness and Perceptions of the Appropriate Use of Antibiotics: A Mixed-Methods Study.

In the outpatient setting, estimates suggest that 30% of the antibiotics prescribed are unnecessary. This study explores patient knowledge and awareness of appropriate use of antibiotics and expectations regarding how antibiotics are used for their treatment in outpatient settings. A survey was administered to a convenience sample of patients, parents, and caregivers (n = 190) at seven primary care clinics and two urgent care locations. Fisher's exact tests compared results by patient characteristics. Although 89% of patients correctly believed that antibiotics work well for treating infections from bacteria, 53% incorrectly believed that antibiotics work well for treating viral infections. Patients who incorrectly believed that antibiotics work well for treating viral infections were more than twice as likely to expect a provider to give them an antibiotic when they have a cough or common cold. Patients who completed the survey also participated in semi-structured interviews (n = 4), which were analyzed using thematic analysis. Patients reported experiencing confusion about which illnesses may be treated by antibiotics and unclear communication from clinicians about the appropriate use of antibiotics. Development of easy to understand patient educational materials can help address patients' incorrect perceptions of appropriate antibiotic use and facilitate patient-provider communication.

Rapid processing of haptic cues for postural control in blind subjects.

OBJECTIVES: Vision and touch rapidly lead to postural stabilization in sighted subjects. Is touch-induced stabilization more rapid in blind than in sighted subjects, owing to cross-modal reorganization of function in the blind? METHODS: We estimated the time-period elapsing from onset of availability of haptic support to onset of lateral stabilization in a group of early- and late-onset blinds. Eleven blind (age 39.4 years±11.7SD) and eleven sighted subjects (age 30.0 years±10.0SD), standing eyes closed with feet in tandem position, touched a pad with their index finger and withdrew the finger from the pad in sequence. EMG of postural muscles and displacement of centre of foot pressure were recorded. The task was repeated fifty times, to allow statistical evaluation of the latency of EMG and sway changes following the haptic shift. RESULTS: Steady-state sway (with or without contact with pad, no haptic shift) did not differ between blind and sighted. On adding the haptic stimulus, EMG and sway diminished in both groups, but at an earlier latency (by about 0.5 s) in the blinds (p <0.01). Latencies were still shorter in the early-than late-blinds. When the haptic stimulus was withdrawn, both groups increased EMG and sway at equally short delays. CONCLUSIONS: Blinds are rapid in implementing adaptive postural modifications when granted an external haptic reference. Fast processing of the stabilizing haptic spatial-orientation cues may be favoured by cortical plasticity in blinds. SIGNIFICANCE: These findings add new information to the field of sensory-guided dynamic control of equilibrium in man.

Equilibrium during static and dynamic tasks in blind subjects: no evidence of cross-modal plasticity.

Can visual information be replaced by other sensory information in the control of static and dynamic equilibrium? We investigated the balancing behaviour of acquired and congenitally blind subjects (25 severe visually impaired subjects--15 males and 10 females, mean age 36 +/- 13.5 SD) and age and gender-matched normal subjects under static and dynamic conditions. During quiet stance, the centre of foot pressure displacement was recorded and body sway analysed. Under dynamic conditions, subjects rode a platform continuously moving in the antero-posterior direction, with eyes open (EO) and closed (EC). Balance was inferred by the movement of markers fixed on malleolus, hip and head. Amplitude of oscillation and cross-correlation between body segment movements were computed. During stance, in normal subjects body sway was larger EC than EO. In blind subjects, sway was similar under both visual conditions, in turn similar to normal subjects EC. Under dynamic conditions, in normal subjects head and hip were partially stabilized in space EO but translated as much as the platform EC. In blind subjects head and hip displacements were similar in the EO and the EC condition; with respect to normal subjects EC, body displacement was significantly larger with a stronger coupling between segments. Under both static and dynamic conditions, acquired and congenitally blind subjects had a similar behaviour. We conclude that long-term absence of visual information cannot be substituted by other sensory inputs. These results are at variance with the notion of compensatory cross-modal plasticity in blind subjects and strengthen the hypothesis that vision plays an obligatory role in the processing and integration of other sensory inputs for the selection of the balancing strategy in the control of equilibrium.