Enhancement of Visuospatial Working Memory by Transcranial Direct Current Stimulation on Prefrontal and Parietal Cortices.

Introduction: Previous studies have reported dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC) activation during the performance of spatial working memory (SWM), therefore this study aims to compare the effect of transcranial direct current stimulation (tDCS) between these two areas. Methods: Fifty-four healthy right-handed students (27 women, 27 men; age=24.3±0.2 years) were randomly assigned to an anodal group (n=27) and a sham group (n=27), each of these groups was divided into F4 (representing right DLPFC) or P4 (representing right PPC) subgroups, respectively. A computerized Corsi block tapping (CBT) task was used to measure SWM. The tDCS intervention consisted of five daily sessions with a direct current of 1.5 mA for 15 minutes on the F4 or P4 area of the brain at 24-hour intervals. Results: Significant enhancement of the SWM span as well as a faster response was observed after anodal tDCS in both the anterior and posterior direction. Moreover, stimulation of the left DLPFC induced a faster reaction time compared to the right PPC. Conclusion: Stimulation DLPFC and PPC, as an element of the frontoparietal network, showed SWM enhancement, with the DLPFC being more affected. Our finding provides new evidence to compare the effect of stimulation on the two main activated cortical areas during visual SWM.

Comparing the Effects of Differential and Visuo-Motor Training on Functional Performance, Biomechanical, and Psychological Factors in Athletes after ACL Reconstruction: A Randomized Controlled Trial.

Variation during practice is widely accepted to be advantageous for motor learning and is, therefore, a valuable strategy to effectively reduce high-risk landing mechanics and prevent primary anterior cruciate ligament (ACL) injury. Few attempts have examined the specific effects of variable training in athletes who have undergone ACL reconstruction. Thereby, it is still unclear to what extent the variations in different sensor areas lead to different effects. Accordingly, we compared the effects of versatile movement variations (DL) with variations of movements with emphasis on disrupting visual information (VMT) in athletes who had undergone ACL reconstruction. Forty-five interceptive sports athletes after ACL reconstruction were randomly allocated to a DL group (n = 15), VT group (n = 15), or control group (n = 15). The primary outcome was functional performance (Triple Hop Test). The secondary outcomes included dynamic balance (Star Excursion Balance Test (SEBT)), biomechanics during single-leg drop-landing task hip flexion (HF), knee flexion (KF), ankle dorsiflexion (AD), knee valgus (KV), and vertical ground reaction force (VGRF), and kinesiophobia (Tampa Scale of Kinesiophobia (TSK)) assessed before and after the 8 weeks of interventions. Data were analyzed by means of 3 × 2 repeated measures ANOVA followed by post hoc comparison (Bonferroni) at the significance level of p ≤ 0.05. Significant group × time interaction effects, main effect of time, and main effect of group were found for the triple hop test and all eight directions, SEBT, HF, KF, AD, KV, VGRF, and TSK. There was no significant main effect of group in the HF and triple hop test. Additionally, significant differences in the triple hop test and the seven directions of SEBT, HF, KF, KV, VGRF, and TSK were found between the control group and the DL and VMT groups. Between group differences in AD and the medial direction of SEBT were not significant. Additionally, there were no significant differences between VMT and the control group in the triple hop test and HF variables. Both motor learning (DL and VMT) programs improved outcomes in patients after ACL reconstruction. The findings suggest that DL and VMT training programs lead to comparable improvements in rehabilitation.

Distinctive characteristics of prolonged standing low back pain developers' and the associated risk factors: systematic review and meta-analysis.

Pain developers (PDs) are considered a pre-clinical low back pain (LBP) population at risk of clinical LBP development and thus exacting great social and economic costs. Therefore, it is necessary to comprehensively investigate their distinctive characteristics and the risk factors of standing-induced LBP based on which appropriate preventive measures can be planned. Scopus, Web of Science, and PubMed databases as well as Google Scholar and ProQuest were systematically searched from inception through 14 July 2022 using a combination of terms relevant to 'standing' and 'LBP'. Studies with low risk of bias in English and Persian using a methodological quality scoring system were deemed eligible for inclusion if they were laboratory studies using prolonged standing duration greater than 42 min to classify adult PDs and non-pain developers (NPDs) without a history of LBP. PDs were compared with NPDs in demographics, biomechanical, and psychological outcomes. Weighted or standardized mean differences, and Hedge's g were generated to determine the pooled effect sizes using STATA software version 17. 52 papers and theses involving 1070 participants (528 PDs and 542 NPDs) were eligible for inclusion in the systematic review 33 of which were used in meta-analyses. Significant differences between PDs and NPDs in terms of movement patterns, muscular, postural, psychological, structural, and anthropometric variables were evidenced. The following factors were found to have a statistically significant association with standing-induced LBP: lumbar fidgets (Hedge's g - 0.72, 95% CI - 1.35 to - 0.08, P = 0.03), lumbar lordosis in participants over 25 years (Hedge's g 2.75, 95% CI 1.89-3.61, P < 0.001), AHAbd test (WMD 0.7, 95% CI 0.36-1.05, P < 0.001), GMed co-activation (Hedge's g 4.24, 95% CI 3.18-5.3, P < 0.001), and Pain Catastrophizing Scale (WMD 2.85, 95% CI 0.51-5.19, P = 0.02). Altered motor control displayed in AHAbd test and higher lumbar lordosis in individuals over 25 years seem to be probable risk factors for standing-induced LBP. In order to detect standing-induced LBP risk factors, future researchers should investigate the association of the reported distinctive characteristics to the standing-induced LBP and that whether they are manipulable through various interventions.

Breakfast consumption is inversely associated with primary headaches in university students: The MEPHASOUS study.

OBJECTIVE: This study was conducted to examine the association between breakfast consumption pattern and primary headaches in a large population of university students. METHODS: This cross-sectional study was done on the MEPHASOUS dataset that contained the information of 83,677 university students, aged ≥18 years, from 28 provinces of Iran. Dietary intakes and breakfast consumption pattern were assessed using a validated self-administered dietary habits questionnaire. Primary headaches were determined according to the International Classification of Headache Disorders-3 (ICHD-3) criteria. Binary logistic regression in different adjusted models was used to assess the association between breakfast consumption and primary headaches. RESULTS: The mean age of participants was 21.50 ± 4.01. Primary headaches were prevalent among 9% of university students. A significant inverse association was seen between breakfast consumption and odds of primary headaches [odds ratio (OR): 0.57, 95 % confidence interval (CI): 0.51-0.62]. This association remained significant even after taking potential confounders into account; such that students who consumed breakfast frequently had 26 % lower odds of primary headaches compared with those who consumed it <1 day/week (OR: 0.74, 95 % CI: 0.65-0.85). Moreover, such a significant inverse association was observed in female students (OR: 0.54, 95 % CI: 0.49-0.61) as well as those with BMI < 25 kg/m2 (OR: 0.68, 95 % CI: 0.58-0.79). However, it became non-significant in male students and those with overweight or obesity. CONCLUSION: We found that frequent breakfast consumption is associated with a decreased odds of primary headaches in female students and those with BMI < 25 kg/m2. Further prospective studies are needed to confirm our findings.

Comparison of some intrinsic risk factors of shoulder injury in three phases of menstrual cycle in collegiate female athletes.

OBJECTIVES: present study aims to investigate the changes in the shoulder joint stability factors during the menstrual cycle. DESIGN: cross-sectional study; SETTING: laboratory. PARTICIPANTS: 15 healthy collegiate female athletes with normal menstrual cycles. MAIN OUTCOME MEASURES: shoulder strength, proprioception, laxity and functional stability were the primary outcomes. Participants were assessed in three phases (mense, ovulation, midluteal (day 21) by 4 different categories of tests, each designed for a different factor. Shapiro-Wilk Test was used to determine normality of data, ANOVA and Friedman Test were used to compare results. Significance level and alpha were considered 95 percent and ≥0.05, respectively. Data shown a relation between proprioception, strength and menstrual cycle. RESULTS: shoulder strength was significantly increased in ovulation phase compared to other phases (p < 0.5) (effect size >0.14). Proprioception was significantly decreased in luteal phase than in mense and ovulation phases (p < 0.5) (effect size >0.14). Finally, ligament laxity and functional stability showed no change in all phases (p < 0.5). CONCLUSION: Menstrual cycle and sexual hormones affect muscle strength and proprioception of shoulder joint, but have no effect on ligament laxity and functional stability.

Dairy consumption in relation to primary headaches among a large population of university students: The MEPHASOUS study.

AIM: To investigate the association between dairy consumption and primary headaches among a large population of university students. METHODS: Totally, 83,622 university students aged 18 years or older were included in the current cross-sectional study. Dietary intakes were assessed using a validated self-administered dietary habits questionnaire. Primary headaches were determined according to the International Classification of Headache Disorders-3 (ICHD-3) criteria. RESULTS: Totally, 9 % of participants suffered from primary headaches. A significant inverse association was observed between dairy consumption and odds of primary headaches (OR: 0.67, 95 % CI: 0.60-0.74). Such inverse association remained significant when potential confounders including demographic variables, physical activity, dietary factors, and BMI were taken into account; such that individuals in the highest category of dairy consumption were 19 % less likely to have primary headaches compared with those in the lowest category (OR: 0.81, 95 % CI: 0.72-0.92). Such an inverse association was also observed in women (OR: 0.79, 95 % CI: 0.68-0.93), but not in men. Stratified analysis based on body mass index revealed a significant inverse association between dairy consumption and primary headaches either in normal-weight individuals or those with overweight or obesity. CONCLUSION: We found that dairy consumption was inversely associated with primary headaches among university students.

Transcranial direct current stimulation on prefrontal and parietal areas enhances motor imagery.

Considering the potential effect of transcranial direct current stimulation (tDCS) to improve motor imagery the purpose of this study was to investigate the effects of tDCS on prefrontal and postparietal cortex in hand mental rotation (HMR). This investigation was a single-blind, randomized study which 60 healthy right-hand college students (30 males and 30 females, age 24.27±0.19 years) volunteered to attend. Using a simple random method, participants were divided into four groups: anodal: F4 (n=15) and P4 (n=15), sham: F4 (n=15) and P4 (n=15). Participants were asked to perform HMR task before and after five sessions of tDCS. Results showed that there is a significant difference between the pretest and post-test of reaction time (t=10.09, d.f.=29, P=0.005) and accuracy (t=-5.04, d.f.=29, P=0.005) in two sites (F4, P4) in anodal group, also two-way analysis of variance of HMR reaction time showed significant main effect of Group (F=52.458, P=0.000, ηP=0.488) indicating faster response in postanodal Group and Site (F=6.561, P=0.013, ηP=0.107) indicating better response in F4, and in HMR accuracy a significant main effect of Group (F=13.659, P=0.001, ηP=0.199) but not for the main effect of Site (F=0.499, P=0.483, ηP=0.009). According to the findings of the study, it is suggested that tDCS on both prefrontal and postparietal cortex could improve HMR with more effect on prefrontal area.

Deficiency in Mental Rotation of Upper and Lower-Limbs in Patients With Multiple Sclerosis and Its Relation With Cognitive Functions.

Mental rotation is a cognitive motor process which was impaired in different neurologic disorders. We investigated whether there were deficits in response pattern, reaction time and response accuracy rate of mental rotation in multiple sclerosis (MS) patients compared to healthy subjects and whether cognitive dysfunctions in MS patients were correlated with mental rotation deficits. Moreover, we showed whether there was a difference between upper and lower-limbs mental rotation in MS patients. Thirty-five MS patients and 25 healthy subjects performed hand mental rotation (HMR) and foot mental rotation (FMR) tasks. Visual information processing speed, spatial learning and memory ability, and visuospatial processing were assessed by Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMT-R), and Judgment of Line Orientation Test (JLO) respectively in MS patients. Reaction time for both hand and foot stimuli increased, and response accuracy rate for hand stimuli decreased in MS patients compared to healthy subjects, but response pattern of mental rotation in MS patients persisted. Similar to healthy subjects, MS patients performed upper-limbs mental rotation more easily than a lower-limbs mental rotation with more speed and response accuracy rate. Reaction time and response accuracy rate were correlated with the mentioned cognitive functions. MS patients made use of the correct response pattern for problem solving of increasing orientation from upright stimuli. Reaction time and response accuracy rate altered in these patients and this alteration might occur along with impairment in motor planning. Subjects' better responding to hand stimuli was due to more familiarity with hand stimuli. The correlation of mental rotation ability with cognitive functions indicates the possible role of cognitive functions in mental rotation.

Abnormalities of mental rotation of hands associated with speed of information processing and executive function in chronic schizophrenic patients.

AIM: Deficits in mental imagery ability have been reported in patients with schizophrenia. However, there is scarce evidence about the correlation between impairment in mental rotation and other cognitive deficits in the patients. The aim of this study was to assess mental rotation ability, along with other measures of cognitive function in patients with schizophrenia. METHODS: The performance of 29 patients with schizophrenia was compared with 29 healthy controls. Mental rotation was measured with the Hand Rotation Task, and cognitive functions were measured with the Brief Assessment of Cognition in Schizophrenia (BACS). RESULTS: On Hand Rotation Task, the patients were significantly slower and less accurate compared to controls. Moreover, mental rotation accuracy was significantly correlated with all the BACS domains except verbal memory. In multiple regression analysis, the two BACS subscales, Tower of London and Symbol Coding tasks, were significant predictors and accounted for 41% of the variance in accuracy in the patients. CONCLUSION: These results support previous findings showing dysfunction of the posterior parietal cortex in schizophrenia, which is involved in general mental rotation, as well as other cognitive processes.