Effects of infant care posture and weight on static postural balance

BACKGROUND

Studies investigating postural balance during various infant care postures have not been reported yet.

OBJECTIVE

The aim of this study was to measure static postural balance when holding an infant dummy in-arms and carrying an infant dummy on back according to different infant dummy weights.

METHODS

Sixteen healthy young subjects participated in a balance test. Infant dummies with weights of 4.6 kg (1-month) and 9.8 kg (12-month) were used in this study. All subjects were asked to naturally stand on a force platform in two infant care postures (holding an infant in-arms and carrying an infant on one's back). Center of pressure (COP) was measured from the force platform. Quantitative variables were derived from the COP. Two-way repeated measure analysis of variance (ANOVA) was performed to determine main effects of infant care postures, infant weight, and their interactions on COP variables.

RESULTS

Back carrying a 12-month infant dummy had the greatest amplitude in all COP variables. Back carrying posture showed significantly greater mean distance and peak power, faster mean velocity, and wider COP area compared to holding posture (P< 0.05). There were significant weight effects of most COP variables mainly in AP direction (P< 0.01).

CONCLUSIONS

Our results could contribute to the prevention of musculoskeletal diseases or prevention of fall due to various infant care activities by developing an assisting device to improve postural balance.

Quantitative Analysis of Postural Balance in Faller and Nonfaller Patients with Parkinson's Disease

Background

Postural instability has been identified as a fall risk factor with a significant impact on the quality of life of patients with Parkinson's disease (PD). The aim of this study was to compare the center of pressure (COP) between faller and nonfaller patients with PD during static standing.

Methods

Thirty-two faller patients and 32 nonfaller patients with PD participated in this study. All patients performed the static balance test on a force plate. COP data were recorded during quiet standing. Mean distance, sway area, mean velocity, mean frequency, and peak power were derived from the COP data. Statistical analysis was performed using independent t-tests to compare faller and nonfaller patients.

Results

Fallers presented a greater average distance, wider sway area, faster average speed, and greater peak power than nonfallers (p < 0.05). In contrast, no significant group differences were observed in peak frequency and mean frequency (p > 0.05).

Conclusions

Although falls occur during dynamic activities, our study demonstrated that even a safe and simple static postural balance test could significantly differentiate between faller and nonfaller patients. Thus, these results suggest that quantitatively assessed static postural sway variables would be useful for distinguishing prospective fallers among PD patients.

Comparison of resting tremor at the upper limb joints between patients with Parkinson's disease and scans without evidence of dopaminergic deficit

BACKGROUND

A representative symptom of Parkinson's disease (PD) is resting tremor. The clinical manifestation of scans without evidence of dopaminergic deficit (SWEDD) is similar to it of PD, though the phenomenology of SWEDD is not well known.

OBJECTIVE

In the present study, the resting tremor of 9 SWEDD patients was quantitatively compared with that of 11 PD patients.

METHODS

Four 3-axis gyro sensors were attached on the index finger, thumb, dorsum of the hand, and arm of the more tremulous side. Root mean square (RMS) angular speed and angular displacement as well as irregularity of angular speed and displacement were derived from the sensor data.

RESULTS

Although disease duration and Hoehn and Yahr stages were comparable, SWEDD patients exhibited different tremor features from PD patients. Significantly faster RMS angular speed and greater RMS angular displacement (p< 0.05) were observed in PD patients than in SWEDD patients. The irregularity of angular displacement of pitch direction at the dorsum of the hand was greater in SWEDD patients than in PD patients (p< 0.05).

CONCLUSION

These results indicate that quantitative indices obtained from resting tremor task could be important biomarkers for identifying potential patients with SWEDD among patients diagnosed with PD.

AGE-RELATED DIFFERENCES IN STATIC POSTURAL BALANCE IN KOREAN ELDERLY ADULTS

Poor postural balance has been related to falls in older people. Although fall rates increase with age, age-related declines in postural balance of older people are still unclear. The goal of this study was to investigate age-related changes in the static postural balance ability of Korean elderly adults. Three hundred and eighty-nine normal elderly adults with ages ranging from 57 years to 87 years participated in this study. All elderly adults were instructed to stand in their preferred natural stance on a self-developed force platform. As postural sway variables, peak frequency, mean frequency, mean velocity, and mean distance were calculated from the center of pressure (COP) trajectories in both the medio-lateral (ML) and antero-posterior (AP) directions. The mean velocity in the older-elderly was significantly faster compared to those of the other age groups particularly in the AP direction ([Formula: see text]). In both the ML and AP directions, the older-elderly group showed a greater mean distance compared to the other age groups ([Formula: see text]). Conversely, no significant age group differences were found in mean frequency and peak frequency ([Formula: see text]). Our results mean that the older-elderly group showed postural balance with faster AP sway speed and overall sway size. The results of our study help in the understanding of age-related declines in postural balance for the prevention of falls and the development of a regression model for normative postural balance ability in Korean elderly adults.

TEST–RETEST RELIABILITY OF STATIC POSTURAL BALANCE VARIABLES IN NATURAL AND FEET-TOGETHER STANCE CONDITIONS

It is important to confirm the reliability of postural balance variables because the results of balance tests would be different with different balance test protocols, i.e., stance conditions such as natural and feet-together stances. The aim of this study was to investigate the test–retest reliability of postural balance variables during the natural and feet-together stance conditions. Sixteen young healthy adults were instructed to sustain their center of body mass as stably as possible on the force plate. As balance standing conditions, natural (a comfortable self-selected stance width) and feet-together stances (placing the feet [Formula: see text] apart) were selected. The mean distance, mean velocity, mean frequency, and 95% confidence ellipse area were derived from the center of pressure (COP) time series in the overall, anteroposterior (AP), and mediolateral (ML) directions. To evaluate the test–retest reliability of the postural balance variables, Cronbach’s alpha coefficient was calculated in each stance condition. Mean velocity was the most reliable variable particularly in three repeated balances within both the natural and feet together stances ([Formula: see text]–0.921). The reliability of all variables of the three balance test was greater than that of the two balance tests, mainly in the natural stance. In contrast, the mean ML distance of the feet-together stance had poor reliability despite three balance tests ([Formula: see text]). These results suggest that the balance test protocol should consider the appropriate stance conditions as well as the number of balance trials to select the reliable postural balance variables.