Influence of gaze distance and downward gazing on postural sway in hemiplegic stroke patients

Gaze distance and head flexion suppress postural sway in healthy subjects. However, the effects of these factors on stroke patients have not been fully elucidated. In this study, we aimed to evaluate the effects of gaze distance and downward gazing on postural sway in stroke patients. We examined 15 stroke patients and 14 elderly controls. Postural sway was measured in the subjects under the following 5 conditions: eyes fixed forward on a marker located 600 cm ahead (600-cm condition); eyes fixed forward on a marker located 150 cm ahead (150-cm condition); eyes fixed downward (downward condition); the subject facing straight ahead but with eyes closed (closed-forward condition); and the subject facing downward but with eyes closed (closed-downward condition). The root mean squares of the anteroposterior (A-P RMS) and the mediolateral (M-L RMS) directions were determined. The results showed that the short gaze distance decreased the M-L RMS in both the stroke patients and controls (p < 0.001, r = 0.66; p = 0.024, r = 0.43, respectively). In the control group, the downward condition increased the M-L RMS when compared with the 600-cm condition (p = 0.011, r = 0.48). The downward condition decreased the A-P and M-L RMS in the stroke patients when compared with the 600-cm condition (A-P RMS: p < 0.001; r = 0.66, M-L RMS: p = 0.001; r = 0.59). Our results showed that the short gaze distance decreased postural sway in both groups, and downward gazing decreased it only in the stroke group.     

Estrogen priming effect on growth hormone (GH) provocative test: a useful tool for the diagnosis of GH deficiency

We have studied the effect of estradiol (E2) on the GH-insulin-like growth factor (GH-IGF) axis in 15 prepubertal GH deficiency (GHD) children and 44 prepubertal or early pubertal children with idiopathic short stature (SS). All of them received a daily dose of micronized E2 (1 or 2 mg) or placebo, for 3 days, before a sequential arginine-clonidine test. In SS children, GH maximal responses were 17.8+/-10.9 on placebo and 27.9+/-14.5 microg/L on estrogen (P < 0.0001). The lower 95% confidence limits for GH maximal response changed from 3.7 microg/L (without E2) to 8.3 microg/L (on E2). In GHD children, no significant stimulatory effect of estrogen on GH levels was observed. After placebo, a cut-off limit of 3.7 microg/L (the lower 95% confidence interval limit) resulted in 73% sensitivity, 95% specificity, and an overall 90% diagnostic efficiency. After E2, a cut-off limit of 8.3 microg/L resulted in a sensitivity of 87%, a specificity of 98%, and a diagnostic efficiency of 95%. After placebo, 68% of SS showed normal IGF-I levels, and the mean did not change on E2 (13.7+/-6.3 vs. 14.3+/-6.8 nmol/L, not significant). In 93% of SS, IGF binding protein (IGFBP)-3 levels were normal during placebo. On E2, mean IGFBP-3 did not change (2.63+/-0.70 vs. 2.70+/-0.70 mg/L, not significant). In 14 of 15 GHD patients, IGF-I values were below normal on placebo, and the mean of the group did not change after E2. During placebo, 13 of 15 GHD children presented low IGFBP-3 values. During E2, there was a small significant increase in IGFBP-3 values (1.06+/-0.58 vs. 1.20+/-0.69 mg/L, P < 0.02). The highest diagnostic efficiencies for IGF-I and IGFBP-3 were observed during placebo (75% and 91%, respectively). We conclude that GH stimulation tests after E2 priming had the highest diagnostic efficiency. Our findings suggest that the effect of estrogen priming on GH stimulated levels, by reducing the number of false nonresponders, might be useful to better discriminate between normal and abnormal GH status in SS children.     

Effect of the Effortful Swallow and the Mendelsohn Maneuver on Tongue Pressure Production against the Hard Palate

Although effortful swallow and the Mendelsohn maneuver are commonly used in dysphagia rehabilitation, little is known about their effects on tongue-palate pressure production. The purpose of this study was to investigate the effects of effortful swallow and the Mendelsohn maneuver on tongue pressure production. Fourteen healthy volunteers (10 men, 4 women; age range = 21–41 years) participated. Tongue pressures during dry swallow, water swallow, effortful swallow, and the Mendelsohn maneuver were measured using a sensor sheet system with five measurement points on the hard palate. Sequential order, duration, maximal magnitude, and the integrated value of tongue pressure at each measurement point were compared among the four tasks. Onset of tongue pressure at the posterior-circumferential parts occurred first in the Mendelsohn maneuver; that at the anterior-median part was earlier than at other parts in the effortful swallow. At all measurement points, tongue pressure duration was significantly longer in the Mendelsohn maneuver than in other tasks. Effortful swallow was most effective in increasing tongue pressure. The integrated value of tongue pressure at the posterior-circumferential parts in the Mendelsohn maneuver and at the median parts in the effortful swallow showed a tendency to increase. These results suggest that tongue pressure increases along a wide part of the hard palate in effortful swallow because the anchor of tongue movement is emphasized at the anterior part of the hard palate. The Mendelsohn maneuver provides prolonged and accentuated tongue-palate contact at the posterior-circumferential parts, which might be important for hyoid-laryngeal elevation during swallowing.     

Evaluation of upper extremity robot-assistances in subacute and chronic stroke subjects

Background  

Robotic systems are becoming increasingly common in upper extremity stroke rehabilitation. Recent studies have already shown that the use of rehabilitation robots can improve recovery. This paper evaluates the effect of different modes of robot-assistances in a complex virtual environment on the subjects' ability to complete the task as well as on various haptic parameters arising from the human-robot interaction.