Higher prevalence of autism in Taiwanese children born prematurely: a nationwide population-based study.

The reported prevalence of autism in preterm and full-term children varies partially because of small sample sizes. Moreover, little is known about the specific factors that contribute to the risk of autism in preterm children. We aimed to compare the prevalence of autism in preterm and full-term children and to identify neonatal risk factors for autism in preterm children using a large national health system database. We analyzed data from 1078 early preterm (<28 weeks of gestation or birth weight<1000 g), 28,947 later preterm (28-36 weeks), and 1,104,071 full-term (≥ 37 weeks) children who were 8-11 years old in 2009. The descending order of prevalence was early preterm (2.2%), later preterm (1.3%), and full-term (0.6%). The prevalence of autism was approximately 2-4 times higher in preterm children than in children born at full-term. The male-female ratio (4:1) in preterm and full-term children was not significantly different. Most of the children were first diagnosed with autism between 3 and 6 years old. Preterm children with autism were not diagnosed earlier than were full-term children. Regression analysis showed that male gender, a very low birth weight, and neonatal cerebral dysfunction were risk factors for autism in the preterm group. We conclude that autism is more prevalent in preterm children. Preventing extremely preterm birth and significant early brain insults may be helpful in reducing the risk of autism in preterm children.

Musculoskeletal symptoms and associated risk factors among office workers with high workload computer use.

OBJECTIVE: Although the prevalence of reported discomfort by computer workers is high, the impact of high computer workload on musculoskeletal symptoms remains unclear. The purpose of this study was to investigate the prevalence of musculoskeletal symptoms for office workers with high computer workload. The association between risk factors and musculoskeletal symptoms was also assessed. METHODS: Two questionnaires were posted on the Web sites of 3 companies and 1 university to recruit computer users in Tainan, Taiwan, during May to July 2009. The 12-item Chinese Health Questionnaire and Musculoskeletal Symptom Questionnaire were chosen as the evaluation tools for musculoskeletal symptoms and its associated risk factors. Chinese Health Questionnaire greater than 5 and computer usage greater than 7 h/d were used to as the cutoff line to divide groups. Descriptive statistics were computed for mean values and frequencies. χ(2) Analysis was used to determine significant differences between groups. A 0.05 level of significance of was used for statistical comparisons. RESULTS: A total of 254 subjects returned the questionnaire, of which 203 met the inclusion criteria. The 3 leading regions of musculoskeletal symptoms among the computer users were the shoulder (73%), neck (71%), and upper back (60%) areas. Similarly, the 3 leading regions of musculoskeletal symptoms among the computer users with high workload were shoulder (77.3%), neck (75.6%), and upper back (63.9%) regions. High psychologic distress was significantly associated with shoulder and upper back complaints (odds ratio [OR], 3.46; OR, 2.24), whereas a high workload was significantly associated with lower back complaints (OR, 1.89). Females were more likely to report shoulder complaints (OR, 2.25). CONCLUSIONS: This study found that high psychologic distress was significantly associated with shoulder and upper back pain, whereas high workload was associated with lower back pain. Women tended to have a greater risk of shoulder complaints than men. Developing an intervention that addresses both physical and psychologic problems is important for future studies.

Assessments of growth conditions on the production of cyanophycin by recombinant Escherichia coli strains expressing cyanophycin synthetase gene.

The synthesis of cyanophycin, a biodegradable polymer, is directed by cyanophycin synthetase. Polymerase chain reaction (PCR) cloned the gene cphA coding for cyanophycin synthetase from Synechocystis sp. PCC 6803 into pET-21b followed by transformation into two Escherichia coli hosts. The culture conditions for cyanophycin production were investigated, and the molecular weight and compositions of purified cyanophycin were analyzed. The results showed that E. coli BL21-CodonPlus(DE3)-RIL could produce 120 mg cyanophycin per gram dry cell weight in terrific medium. The purified cyanophycin consisted of insoluble and soluble forms at pH 7. The insoluble form had a higher molecular weight (20-32 kDa) than the soluble form (14-25 kDa). Both forms are composed of three major amino acids, aspartic acid, arginine, and lysine, and the insoluble form showed a higher arginine/lysine molar ratio (4.61 ± 0.31) than the soluble form (0.89 ± 0.05). In addition, the nitrogen sources could affect the yields of insoluble and soluble forms of cyanophycin. The medium containing additional lysine could enhance the proportion of the soluble form, but had little effect on the lysine and arginine percentages of both soluble and insoluble forms. The medium containing additional arginine slightly decreased the proportion of soluble form and altered its amino acid composition, with a minimal effect on the lysine and arginine percentages in the insoluble form.

The effect of aging on muscle activation and postural control pattern for young and older computer users.

A lot of older adults try to learn to use computers and might use different ways to perform a computer task compared to younger people. Fifteen healthy young and 15 healthy older adults participated in this study and all performed a series of mouse tasks. A three dimensional motion capture system and electromyographic analysis were used to obtain kinematic and kinetic data during performing the computer tasks. Three-way analysis of variance with repeated measures on task and time factors was used to analyze all dependent measurements. Older adults had higher RMS of forearm muscles compared to the young adults. The RMS of the finger extensor was highest when performing a dragging task. Compared with young adults, the older adults had greater cranial-cervical angle and neck flexion, but smaller head flexion, shoulder angle, elbow angle and ulnar deviation. Consequently, the older adults might have a greater risk of developing musculoskeletal disorder.

Comparison of posture and muscle control pattern between male and female computer users with musculoskeletal symptoms.

The primary purpose of this study was to compare the posture and muscle control patterns between male and female computer users with musculoskeletal symptoms. Forty computer users were recruited. Each subject performed a preferred speed typing, a fast speed typing, and a repetitive mouse task. The independent variables were gender, typing speed, and time. There were significant differences between genders for head and neck flexion angles when they were performing the preferred speed typing task. Significant differences between genders were also found for upper extremity angles when they were performing the repetitive mouse task. Male computer users had a smaller root mean square of the right extensor digitorium than females. In general, postural differences were significant between genders, even when the subjects' table and chair were adjusted to meet their anthropometry. Our results suggest that modifications of the computer working environment may be different between genders.

Age-related changes of arm movements in dual task condition when walking on different surfaces.

The purpose of this study was to investigate whether the dual task paradigm would influence arm movements during walking. Furthermore, we examined the effects of different walking surfaces on arm movements while performing dual tasks. The effects of age and gender were also investigated. Fifteen young adults and 15 older adults were included in this study. Subjects were asked to perform the walking task alone (single-task trial) and walking in combination with a cognitive task (dual-task trial). Four walking conditions (1 single task and 3 dual task trials)×two walking surfaces were encountered. Both age groups had greater elbow and trunk movement in the sagittal plane under the dual task trials as compared to the single task trial (p<.05). Subjects had greater upper extremity and upper body movement on the soft floor than on the hard floor (p<.05). Subjects had greater movement amplitude when confronting a challenging environment, especially in the contralateral side. Among gender, there was a group-gender interaction: the older females had smaller upper extremity movement than the older males (p<.05) but the opposite was true for the young adults. The results suggest that different age groups of males and females use different balance control strategy to deal with the challenging conditions.

Using risk factors, myoelectric signal, and finger tremor to distinguish computer users with and without musculoskeletal symptoms.

Most of previous studies use questionnaire to assess risk factors for cumulative trauma disorders of the upper extremity (CTDUE) for computer workers. Few studies combine both physical examination and questionnaire to assess musculoskeletal symptoms. Fifteen symptomatic and 15 non-symptomatic computer users were recruited. Both of them were asked to perform a repetitive tapping task (200 taps/min) as the fatigue task. Tremor of the index finger and surface electromyography (EMG) of the flexor digitorum superficial (FDS) were collected prior and after the tapping task. Muscle strength and range of motion for right wrist were collected before the tapping task. All subjects were asked to fill out the questionnaire about risk factors of CTDUE. Female users in the symptomatic group had weaker wrist extensor strength than those in the non-symptomatic group (P < 0.05). After performing the tapping task, FDS strength and median frequency of the FDS EMG at 25%, and 100% maximal voluntary contraction (MVC) for the symptomatic group decreased (P < 0.05). However, no significant differences were found in strength and median frequency of the FDS EMG between prior and after tapping task in the non-symptomatic group. There was no significant difference for root mean square of the finger tremor between and within groups. Regression analysis revealed that median frequency of the FDS EMG at 25% MVC, age, total time spent on computer, and mouse position were better factors to classify computer users into the symptomatic group compared to other factors obtained from questionnaire and physical exam. Besides, symptomatic computer users seem to have longer experience of computer use than non-symptomatic users. After the fatigue task, the symptomatic users decreased their muscle strength to a larger extent than the non-symptomatic users.

Survey of faulty postures and associated factors among Chinese adolescents.

OBJECTIVE: This study investigates the prevalence of common faulty postures among adolescents and identify if significant relationships existed among the number of faulty postures, psychologic distress, and musculoskeletal symptoms. METHODS: The Musculoskeletal Questionnaire and Chinese Health Questionnaire were randomly distributed to 300 high school students in the Tainan area. On-campus postural screening, which included digital photography, manual muscle tests, and flexibility tests, was also performed. RESULTS: Two hundred eighty-seven participants completed all of the evaluations. The most common faulty posture was uneven shoulder level (36%), followed by forward head posture (25%). There was a sex difference between groups. The incidence of forward head posture for the male students was higher than that of the female students (P < .0001). In addition, the high psychologic distress group tended to have a higher prevalence of uneven shoulder height than that of the low psychologic distress group (P < .0001). As for the correlation analysis, the researchers did not find a high correlation among the scores of the faulty posture, psychologic distress, and musculoskeletal symptoms. CONCLUSION: The results of this study show that the incidence of faulty posture was high for the adolescent group, especially for the uneven shoulder level. Subjects' awareness about being assessed might decrease the incidence for some faulty posture. However, the relationships among the number of faulty postures, psychologic distress, and musculoskeletal symptoms were low. We suggest that there are multiple factors that might contribute to musculoskeletal symptoms; faulty posture could be one important factor that causes symptoms.

A Comparison between young and old adults in their ability to rapidly sidestep during gait when attention is divided.

BACKGROUND: The incidence of falls among older adults is high and the risk factors are often complex in nature. Considerable research has been done in the area of age-related changes of balance in an attempt to better understand the increased risk of falls. Studies of cognitive changes, however, suggest that the elderly are less able to divide their attention between two or more activities. This inability to divide attention could explain the increased risks of falls in the elderly. OBJECTIVE: To investigate the effects of divided attention, age and prior knowledge of movement path, on kinetic measures and the position of the sacral marker relative to the center of pressure (COP) when individuals perform a rapid sidestep during walking. METHODS: 32 young and 32 old adults participated in this study. Subjects walked and took a sidestep without interrupting forward progression. An arithmetic task was performed during half of the walking trials with the sidestep direction preplanned or unknown. Peak lateral ground reaction force, mean distance between COP and sacrum, walking velocity, performance speed and accuracy of the cognitive task were measured. RESULTS: Both groups significantly decreased their mediolateral distance between the sacral marker and the COP in the dual-task trials (p = 0.04). Both groups significantly decreased their walking speed in the dual-task trials (p < 0.0001). Prior knowledge of the sidestep direction significantly affected the peak lateral ground reaction force and the sacral marker to COP distance but the differences were age-dependent. Young adults had a larger value in the unknown condition than in the preplanned condition (p < 0.0001). For the cognitive task, both groups decreased their performance speed (p < 0.0001) but maintained their performance accuracy as compared to the baseline data (p > 0.05). CONCLUSIONS: Our results revealed that old adults tended to be conservative, when facing the dual-task trials or unknown test condition. The fact that the older adults in the current study did not perform similarly to the younger adults suggests that they might have a fear of fall when facing a challenging balance task.

Contrast of directional influence upon motor overflow between submaximal and maximal static exertions.

This study investigated exertion-dependent motor overflow among healthy adults when they performed isometric tasks with contralateral joints in different task directions. Twenty healthy adults (10 males and 10 females, mean age = 26.2 yrs) were instructed to complete a set of isometric contractions of various force vectors with the shoulder, elbow, and wrist joints, in a total of ten motor tasks at submaximal and maximal intensities (50%, 100% maximal voluntary contractions). The electromyographical activities from eight muscles of the unexercised upper limb were recorded to characterize intensity of motor overflow during sustained isometric contraction. Both occurrence frequency and magnitude of motor overflow in terms of standardized net excitation (SNE) increased with exertion level for all joint movements (P < 0.001). Additionally, the motor overflow magnitude depended strongly on the task direction of maximal isometric contraction (P < 0.05). Motor overflow was particularly augmented by the contralateral isometric contractions where task directions were opposed to gravity. However, such a directional effect upon SNE was not evident during submaximal contraction (P > 0.05). The difference of the net excitation between maximal and submaximal contraction (DNE(100%-50%MVC) data) indicated that the pectoralis major and triceps brachii consistently exhibited a marked recruitment in reaction to change in task direction of isometric contraction. Patterned motor overflow may be physiologically relevant to topological mapping of the ipsilateral pathways and altered effectiveness of use-dependent interhemispherical connectivity. The current observations provide better insight into gain in muscle strength due to contralateral exercise.

Electromyographic analysis of joint-dependent global synkinesis in the upper limb of healthy adults: laterality of intensity and symmetry of spatial representation.

The intensity and spatial representation of electromyographical (EMG) activity were examined to characterize the effects of limb dominance and movement direction upon global synkinesis (GS). Twenty-two healthy young subjects (11 men, 11 women) with a mean age of 24.7 years participated in this study. Three trials of EMG activities from eight primary muscles in the unexercised limb were recorded when a maximal isometric contraction in various directions was performed by the shoulder, elbow, and wrist of the dominant and non-dominant upper limbs. The features of GS, including intensity and spatial representation, were quantified with standardized net excitation levels (SNE) and relative excitation (RE), respectively. Our data indicated that (1) GS intensity was strongly limb-dependent with a larger SNE level arising when target joints of the non-dominant upper limb were active, (2) the GS intensity was more influenced by movement direction of the non-dominant limb than by that of the dominant limb, (3) the gradient change in GS intensity was observed bilaterally with a larger SNE level associated with contralateral movements of a proximal joint than a distal joint, and (4) GS spatial representations of the upper limbs were patterned and symmetrical, but seemly insensitive to movement direction. Laterality in GS intensity and structured GS spatial representation with symmetry could be a consequence of use-dependent hemispheric organization.

The association between psychological distress and musculoskeletal symptoms experienced by Chinese high school students.

STUDY DESIGN: A cross-sectional nonexperimental study. OBJECTIVES: To determine the prevalence of musculoskeletal symptoms during a 6-month period and explore the contributing factors associated with these symptoms in Chinese senior class high school students. We also explored the relationship between psychological distress and musculoskeletal symptoms in this population. BACKGROUND: Musculoskeletal symptoms with no underlying identifiable pathology are a management puzzle to medical professionals. Finding the prevalence of musculoskeletal symptoms is the first step in the prevention of further chronic pain syndromes in young adults. No study, however, has directly measured the prevalence of musculoskeletal symptoms in this population. Investigations of the contributing factors to these symptoms, though rare, can provide information to assist in the prevention of further injuries. METHODS: The Musculoskeletal Symptom Questionnaire (MSQ) and the 12-question version of the Chinese Health Questionnaire (CHQ-12) were randomly distributed to students (n = 550) in 4 different high schools in the Tainan area of Taiwan. Of these, 471 students returned the questionnaires for analysis. Descriptive statistics were computed for means, standard deviations, and frequencies. Chi-square statistics were used for analysis of the association between psychological distress and musculoskeletal symptoms. RESULTS: The most frequent complaints of musculoskeletal symptoms among the adolescent Chinese student population were reported as being located in the following anatomical areas: neck (56%), shoulder (45%), and back (37%). Based on the results from the CHQ-12, all of the participants were divided into 2 groups: a high psychological (CHQ-12 score > or = 5) and a low psychological (CHQ-12 score < 5) distress group. There were significant differences of prevalence of musculoskeletal symptoms between these 2 groups (P < .05), especially for the neck region (P = .003). CONCLUSION: The results showed that the prevalence of musculoskeletal symptoms was high in this adolescent population and demonstrated a certain association with psychological distress. We suggest that surveys of this type may serve as preclinical detectors of future musculoskeletal disorders and may permit early interventions. Developing an intervention that addresses both physical and psychological problems may be beneficial for this population.