Laterality and otorhinolaryngology: a review.

BACKGROUND: Laterality of paired organs involves the function of the eyes, ears, hands and feet. Whilst most people have a right-handed preference, about 10 per cent are left-handed. Similarly, the right eye is usually preferred to the left. Medicine is both taught and practised for those with right hand and eye preference, and left-handed medical students and doctors must negotiate the right-handed world. OBJECTIVE: This brief review looks at society's attitudes, medical training and the practice of otolaryngology in the UK towards laterality and handedness. METHOD: Literature review. RESULTS: Studies suggest that left-handers are more versatile and so are more ambidextrous. Conversely, this may result in problems when a right-hander tries to undertake a procedure with the non-dominant hand. CONCLUSION: Cultures and attitudes are changing towards those who are left-handed. Left-handed surgeons may encounter difficulties in the clinical environment throughout their training.

Inventories of Human Lateral Preference: A Systematic Review.

There are a variety of inventories available to evaluate human lateral preference, but no previous review has systematically analyzed and compared them. We conducted a systematic literature review to identify these inventories and describe their characteristics (e.g., dimensions, scales, tasks, psychometric properties). We included 26 articles, each presenting a different inventory to assess lateral preference, published between 1900 and 2022, selected from the following databases: PubMed, SportDiscus, APA PsycNET, and Web of Science. These inventories analyzed tasks performed in everyday life (domestic, work-related, sports, and leisure/recreation activities), covering hand, foot, hearing, visual and other non-usual lateral preference dimensions, such as trunk and head. Most inventories classified individuals based on the direction (left, indifferent or right preference) and degree (consistent or moderate) of laterality. However, many of the reviewed inventories lack established psychometric verification in their original publication, such as validity, reliability, responsiveness, and practical applicability. Inventories also presented tasks that may be specific to a given cultural setting, limiting their application across different countries. Based on these findings, we provide a comprehensive guide for researchers to select a lateral preference assessment tool, but also advocate for a new inventory with a broader approach, containing more than one dimension of lateral preference (i.e., not only handedness) and tasks that are common to different cultures to enhance practical applicability worldwide.

Fluoroscopy-based robotics in total hip arthroplasty mitigates laterality-based differences in acetabular cup placement when compared to the manual, fluoroscopic- assisted technique.

BACKGROUND: Robotic assistance in total hip arthroplasty (RA-THA) has been shown to minimize laterality-based differences in acetabular cup positioning. OBJECTIVE: To determine if the use of a novel, fluoroscopy-based RA-THA system mitigates differences in acetabular cup placement between left (L) and right (R) side hip procedures, when compared to manual, fluoroscopic-assisted technique. METHODS: We conducted a retrospective review of 106 consecutive mTHA (40 L/66 R) and 102 RA-THA (48 L/54 R) primary direct anterior approach procedures. All cases were performed by a single right-hand-dominant surgeon, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Outcomes included acetabular cup inclination and anteversion, and the proportion of cups within the Lewinnek safe-zone. RESULTS: The average inclination of mTHA L cases was smaller than that of mTHA R cases (41.10∘± 7.38 vs. 43.97∘± 6.27; p= 0.04). For RA-THA, L and R cup angles were similar. There were fewer overall mTHA hips within the Lewinnek safe-zone compared to RA-THA (0.59 vs. 0.78; p= 0.003), as well as fewer mTHA R cases than RA-THA R cases (0.59 vs. 0.80; p= 0.03) within safe zone. CONCLUSION: Use of a novel, fluoroscopy-based robotic system mitigates laterality-based differences in acetabular cup placement that were observed in a manual, fluoroscopic-assisted cohort.

Functional MRI but not white matter fibre dissection identifies language dominance.

OBJECTIVES: Lateralisation of some language pathways has been reported in the literature using diffusion tractography, which is more feasible than functional magnetic resonance imaging (fMRI) in challenging patients. Our retrospective study investigates whether a correlation exists between threshold-independent fMRI language lateralisation and structural lateralisation using tractography in healthy controls and brain tumour patients. METHODS: Fifteen healthy subjects and 61 patients underwent language fMRI and diffusion-weighted MRI. A regional fMRI laterality index (LI) was calculated. Tracts dissected were the arcuate fasciculus (long direct and short indirect tracts), uncinate fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus and frontal aslant tract. An asymmetry index (AI) for each tract was calculated using tract volume analysed with single tensor (ST) and spherical deconvolution (SD) models, as well as hindrance modulated orientational anisotropy (HMOA) for SD tracts. Linear regression assessed the correlation between LI and AI. RESULTS: In all subjects, there was no significant correlation between LI and AI for any of the dissected tracts. Significant correlations were only found when handedness for controls and tumour volume for patients were included as covariates. In handedness subgroups, the average AI of some tracts showed the same laterality as LI, and some the opposite. Discordant results were observed for ST- and SD-based AIs. CONCLUSIONS: Our results do not support using tractography in the assessment of language lateralisation. The discordant results between ST and SD indicate that either the structural lateralisation of dissected tracts is less robust than functional lateralisation, or tractography is not sensitive methodology. Other diffusion analysis approaches should be developed. CLINICAL RELEVANCE STATEMENT: Although diffusion tractography may be more feasible than fMRI in challenging tumour patients and where sedation or anaesthesia is required, our results do not currently recommend replacing fMRI with tractography using volume or HMOA in the assessment of language lateralisation. KEY POINTS: • No correlation found between fMRI and tractography in language lateralisation. • Discordance between asymmetry indices of different tractography models and metrics. • Tractography not currently recommended in language lateralisation assessment.

Severe cholinergic terminal loss in newly diagnosed dementia with Lewy bodies.

Cholinergic changes play a fundamental role in the natural history of dementia with Lewy bodies and Lewy body disease in general. Despite important achievements in the field of cholinergic research, significant challenges remain. We conducted a study with four main objectives: (i) to examine the integrity of cholinergic terminals in newly diagnosed dementia with Lewy bodies; (ii) to disentangle the cholinergic contribution to dementia by comparing cholinergic changes in Lewy body patients with and without dementia; (iii) to investigate the in vivo relationship between cholinergic terminal loss and atrophy of cholinergic cell clusters in the basal forebrain at different stages of Lewy body disease; and (iv) to test whether any asymmetrical degeneration in cholinergic terminals would correlate with motor dysfunction and hypometabolism. To achieve these objectives, we conducted a comparative cross-sectional study of 25 newly diagnosed dementia with Lewy bodies patients (age 74 ± 5 years, 84% male), 15 healthy control subjects (age 75 ± 6 years, 67% male) and 15 Parkinson's disease patients without dementia (age 70 ± 7 years, 60% male). All participants underwent 18F-fluoroetoxybenzovesamicol PET and high-resolution structural MRI. In addition, we collected clinical 18F-fluorodeoxyglucose PET images. Brain images were normalized to standard space and regional tracer uptake and volumetric indices of basal forebrain degeneration were extracted. Patients with dementia showed spatially distinct reductions in cholinergic terminals across the cerebral cortex, limbic system, thalamus and brainstem. Also, cholinergic terminal binding in cortical and limbic regions correlated quantitatively and spatially with atrophy of the basal forebrain. In contrast, patients without dementia showed decreased cholinergic terminal binding in the cerebral cortex despite preserved basal forebrain volumes. In patients with dementia, cholinergic terminal reductions were most severe in limbic regions and least severe in occipital regions compared to those without dementia. Interhemispheric asymmetry of cholinergic terminals correlated with asymmetry of brain metabolism and lateralized motor function. In conclusion, this study provides robust evidence for severe cholinergic terminal loss in newly diagnosed dementia with Lewy bodies, which correlates with structural imaging measures of cholinergic basal forebrain degeneration. In patients without dementia, our findings suggest that loss of cholinergic terminal function occurs 'before' neuronal cell degeneration. Moreover, the study supports that degeneration of the cholinergic system is important for brain metabolism and may be linked with degeneration in other transmitter systems. Our findings have implications for understanding how cholinergic system pathology contributes to the clinical features of Lewy body disease, changes in brain metabolism and disease progression patterns.

Futuros cirurgiões-dentistas canhotos graduandos da Universidade Federal de Uberlândia: perfil, dificuldades e dores osteomusculares / Future left-handed dentists graduating from the Federal University of Uberlândia: profile, difficulties and musculoskeletal pain

Os indivíduos canhotos necessitam de utensílios para concretização de suas atividades diárias, bem como, para o exercício da prática odontológica onde a escassez de equipamentos específicos pode refletir em desgaste corporal, com isso, o presente trabalho tem por objetivo identificar os estudantes canhotos do curso de Odontologia da Universidade Federal de Uberlândia além de identificar suas dificuldades, queixas e locais de dores osteomusculares nas atividades laboratoriais e clínicas. Métodos: Foram incluídos todos os alunos canhotos matriculados no ano de 2021. Foram aplicados questionários on line para coletar os dados dos alunos. Resultados: Foram tabulados e como resultados, encontrou-se que os canhotos representam 5,6% do total de alunos do curso de Odontologia, a maioria são mulheres (66,7%), com média de idade de 21 anos. O segundo período foi o que apresentou maior número de canhotos (25%). As atividades práticas do curso, estas foram cursadas por 91,7% dos entrevistados, que relataram com maior frequência usar a mão esquerda (62,5%), sentar na posição de 1 hora (20,8%) e ter maior dificuldade ao tratar o quadrante superior direito (45,8%). Os locais mais citados de dores osteomusculares após realizar essas atividades, foram: punhos e mãos (62,5%), parte inferior das costas (62,5%) e pescoço (58,3%). Conclusão: Os canhotos representam a minoria dos alunos e suas dificuldades são, a falta de estrutura física adequada e a incompreensão das pessoas ao redor. Em relação a queixa de dor ou desconforto, mãos, punhos, parte inferior das costas e pescoço foram os membros mais citados no estudo(AU)

Left-handed individuals need tools to carry out their daily activities, as well as for the exercise of dental practice where the scarcity of specific equipment can reflect on body wear, with this, the present work aims to identify left-handed students of the course of Dentistry at the Federal University of Uberlândia, in addition to identifying their difficulties, complaints and sites of musculoskeletal pain in laboratory and clinical activities. Methods: All left-handed students enrolled in the year 2021 were included, and three questionnaires were applied online to identify the profile of students and the difficulties encountered in laboratory and clinical practice. Results: They were tabulated and as a result, it was found that left-handers represent 5.6% of the total number of students in the Dentistry course, most of them are women (66.7%), with a mean age of 21 years. The second period was the one with the highest number of left-handers (25%). The practical activities of the course were carried out by 91.7% of the interviewees, who reported more frequently using their left hand (62.5%), sitting in the 1 o'clock position (20.8%) and having greater difficulty when treat the upper right quadrant (45.8%). The most cited sites of musculoskeletal pain after performing these activities were: wrists and hands (62.5%), lower back (62.5%) and neck (58.3%). Conclusion: Lefthanded people represent the minority of students, and their difficulties are the lack of adequate physical structure and the misunderstanding of the people around them. In relation to complaints of pain or discomfort, hands, wrists, lower back and neck were the most cited members in the study(AU)

Neuroplasticity Following Stroke from a Functional Laterality Perspective: A fNIRS Study.

To explore alterations of resting-state functional connectivity (rsFC) in sensorimotor cortex following strokes with left or right hemiplegia considering the lateralization and neuroplasticity. Seventy-three resting-state functional near-infrared spectroscopy (fNIRS) files were selected, including 26 from left hemiplegia (LH), 21 from right hemiplegia (RH) and 26 from normal controls (NC) group. Whole-brain analyses matching the Pearson correlation were used for rsFC calculations. For right-handed normal controls, rsFC of motor components (M1 and M2) in the left hemisphere displayed a prominent intensity in comparison with the right hemisphere (p < 0.05), while for stroke groups, this asymmetry has disappeared. Additionally, RH rather than LH showed stronger rsFC between left S1 and left M1 in contrast to normal controls (p < 0.05), which correlated inversely with motor function (r = - 0.53, p < 0.05). Regarding M1, rsFC within ipsi-lesioned M1 has a negative correlation with motor function of the affected limb (r = - 0.60 for the RH group and - 0.43 for the LH group, p < 0.05). The rsFC within contra-lesioned M1 that innervates the normal side was weakened compared with that of normal controls (p < 0.05). Stronger rsFC of motor components in left hemisphere was confirmed by rs-fNIRS as the "secret of dominance" for the first time, while post-stroke hemiplegia broke this cortical asymmetry. Meanwhile, a statistically strengthened rsFC between left S1 and M1 only in right-hemiplegia group may act as a compensation for the impairment of the dominant side. This research has implications for brain-computer interfaces synchronizing sensory feedback with motor performance and transcranial magnetic regulation for cortical excitability to induce cortical plasticity.

Right hemisphere brain lateralization for knee proprioception among right-limb dominant individuals.

Introduction: Studies indicate that brain response during proprioceptive tasks predominates in the right hemisphere. A right hemisphere lateralization for proprioception may help to explain findings that right-limb dominant individuals perform position matching tasks better with the non-dominant left side. Evidence for proprioception-related brain response and side preference is, however, limited and based mainly on studies of the upper limbs. Establishing brain response associated with proprioceptive acuity for the lower limbs in asymptomatic individuals could be useful for understanding the influence of neurological pathologies on proprioception and locomotion. Methods: We assessed brain response during an active unilateral knee joint position sense (JPS) test for both legs of 19 right-limb dominant asymptomatic individuals (females/males = 12/7; mean ± SD age = 27.1 ± 4.6 years). Functional magnetic resonance imaging (fMRI) mapped brain response and simultaneous motion capture provided real-time instructions based on kinematics, accurate JPS errors and facilitated extraction of only relevant brain images. Results: Significantly greater absolute (but not constant nor variable) errors were seen for the dominant right knee (5.22° ± 2.02°) compared with the non-dominant left knee (4.39° ± 1.79°) (P = 0.02). When limbs were pooled for analysis, significantly greater responses were observed mainly in the right hemisphere for, e.g., the precentral gyrus and insula compared with a similar movement without position matching. Significant response was also observed in the left hemisphere for the inferior frontal gyrus pars triangularis. When limbs were assessed independently, common response was observed in the right precentral gyrus and superior frontal gyrus. For the right leg, additional response was found in the right middle frontal gyrus. For the left leg, additional response was observed in the right rolandic operculum. Significant positive correlations were found between mean JPS absolute errors for the right knee and simultaneous brain response in the right supramarginal gyrus (r = 0.464, P = 0.040). Discussion: Our findings support a general right brain hemisphere lateralization for proprioception (knee JPS) of the lower limbs regardless of which limb is active. Better proprioceptive acuity for the non-dominant left compared with the dominant right knee indicates that right hemisphere lateralization may have meaningful implications for motor control.

The development of hand, foot, trunk, hearing, and visual lateral preference throughout the lifespan.

This research investigated the developmental process of five lateral preference dimensions (hand, foot, trunk, hearing, and visual preference). A total of 1236 volunteers participated in this study, divided into five age groups: 07-12 (n = 247); 13-17 (n = 234); 18-30 (n = 227); 31-60 (n = 225); and 61-90 years old (n = 303). Lateral preference was assessed via questionnaire with the Global Lateral Preference Inventory. By assessing the degree and direction of lateral preference in different ages, our results revealed a pattern of lateralization strengthening with aging in all the analyzed dimensions. We also verified significant correlation between hand preference and the other dimensions for all age groups, but correlation was stronger in the 7-12 group for all correlation pairs. Our results lead to the suggestion of an underlying general lateralization process in early ages (7-12 years old) followed by specific developmental trajectories of each preference dimension (13 years forward), likely startled by hemisphere and functional specialization related to innate developmental patterns of neural structures and social/environmental influences.

Difficulties of dental practice among left-handed Tunisian students: a cross-sectional survey

Abstract In dentistry, most equipment is designed for right-handed (RH) individuals. Thus, left-handed (LH) individuals are often forced to adapt to demanding RH working conditions, and therefore, experience difficulties in their practice. The objective of this study was to determine the prevalence of left handedness among dental students at the Dental Clinic of Monastir, Tunisia, and to investigate the difficulties for LH individuals during clinical practice. A cross-sectional study was conducted among dental students during the academic year from September 2019 to March 2020. An adaptation of the Grad-Corllet Diagram and a specific questionnaire on clinical practices were administered to 221 participants. Data were analyzed using SPSS 24.0 statistical software for descriptive statistics and the chi-square test was performed (with a 5% significance level). The study revealed that 18.1% of dental students were LH. Among which, 82.5% of LH students had difficulties using instruments designed for RH dentists, 47.5% of LH students preferred the 3 o'clock working position, and 77.5% of LH students preferred to work in a sitting position. Most LH students (70%) reported that endodontic treatment was the most difficult procedure to perform. All students, whether RH or LH, presented a higher percentage of pain in the lumbar and neck/cervical regions; however, LH students presented higher values (77.5%) with statistically significant differences being reported for lower back pain (p = 0.026) and neck pain (p = 0.012). This study highlights the difficulties that LH dental students face in performing dental work. Dental Schools should provide LH students with appropriate equipment and a proper learning environment.

Investigation of Factors Affecting the Side of the Disease Onset in Parkinson's Disease.

Introduction: Parkinson's disease (PD) is a progressive neurodegenerative disease that starts unilaterally in almost all cases and tends to emerge on the side of the dominant hand, but what we know about the cause of this lateralization is limited. Frequent use of the extremity and physical activity are argued to be protective from PD in preclinical and clinical studies. This study aimed to evaluate the effect of handedness and working in occupations that require continuous use of upper extremities on the disease onset-side. Methods: We retrospectively collected 84 PD patients who applied to Koç University Neurology outpatient clinic between July 2016-October 2018. We analyzed the parameters of the side and region of disease onset, age of onset, number of drugs used for PD, hand preference, and patients' occupations. Results: The median age of our study group was 61 (53-69). Thirty (36%) of the 84 patients were women. Seventy-nine patients (94%) were right-handed. Eighty-three (99%) had asymmetric onset. The disease started on the dominant hand side in 47 patients (57%) and on the non-dominant hand side in 36 (43%) patients. In our group with a median disease duration of four (2-7) years, the side with more severe complaints measured with the Unified Parkinson's Disease Evaluation Scale was consistent with the onset-side of the disease (p<0.001). In addition, the number of drugs used for PD and the scale score were higher in patients with longer disease duration (p=0.039, p=0.005). The number of drugs used for PD was also higher in patients with lower extremity-onset or both upper and lower extremities affected simultaneously than the upper extremity-onset (p=0.005). While the probability of starting on the dominant side was 43% in patients working in occupations requiring continuous use of upper extremities, it was 65% in others (p=0.027). Conclusion: According to this study, the onset of PD tends to be on the dominant hand side. Continuous upper extremity use may reduce the possibility of starting on the dominant side.

Análise de indicadores antropométricos em indivíduos com e sem síndrome de Down / Analysis of anthropometric indicators in individuals with and without Down syndrome

Objetivo: este estudo buscou averiguar a possível discrepância bilateral de indicadores antropométricos de pessoas com e sem síndrome de Down (SD). Material e Método: para tal, contou-se com a participação de 60 indivíduos com e sem síndrome de Down, com idades entre 11 e 14 anos, que foram avaliados quanto à dominância lateral, dobras cutâneas, percentual de gordura, circunferência muscular de braço e antebraço e força de preensão palmar. Principais resultados: notou-se maior número de indivíduos sinistros e com indefinição na lateralidade no grupo com síndrome de Down do que nas pessoas com desenvolvimento típico. Os valores da percentagem de gordura, das medidas de dobra cutânea, da circunferência muscular do braço e da circunferência de antebraço foram maiores entre os participantes com síndrome de Down do que entre os do grupo controle. A força de preensão palmar foi maior nos indivíduos típicos. Não houve diferença na composição corporal bilateral dos indivíduos com síndrome de Down. Conclusão: os resultados encontrados demonstraram a existência de uma simetria bilateral nos indivíduos com e sem síndrome de Down.

Objective: this study sought to investigate the possible discrepancy in the bilateral anthropometric indicators of people with and without Down syndrome (DS). Material and Method: 60 individuals with and without Down syndrome, aged between 11 and 14 years, who were evaluated for lateral dominance, skinfolds, fat percentage, arm and forearm muscle circumference, and hand grip strength. Main results: there were a greater number of sinister individuals with a vagueness in laterality in the group with Down syndrome than in people with typical development. The percentage of fat, skinfold measurements, arm muscle circumference and forearm circumference were higher among participants with Down syndrome than those in the control group. Hand grip strength was greater in typical individuals. There was no difference in the bilateral body composition of individuals with Down syndrome. Conclusion: the results found demonstrated the existence of a bilateral symmetry in individuals with and without Down syndrome.

Cultural and environmental aspects influence lateral preferences.

Transcultural approaches comparing the distribution of lateral preference between countries focused primarily on handedness. However, other laterality dimensions may also be susceptible to cultural variations. The present study compared lateral preference in five dimensions (hand, foot, trunk, hearing, and visual) of young adults from Brazil and Mozambique. Two hundred and two undergraduate students participated in the study, of which 101 were Brazilian (21.7 ± 1.66 years old) and 101 Mozambican (25.6 ± 6.2 years old). The participants' lateral preference direction and degree were assessed using the global lateral preference inventory. Most Brazilians were classified in the moderate preference category, while Mozambicans had a higher frequency of individuals with strong preferences. Hence, Mozambicans presented a higher lateralization degree for all dimensions. A subsequent analysis considering only preference direction (right, left or indifferent), and not degree, did not show the same outcomes, revealing similarities in preference distribution between the two groups. This finding highlights the necessity to incorporate preference degrees in future analysis to not overlook potential differences. We also conclude lateral preference investigations with transcultural approaches should analyse beyond handedness, as other dimensions can also be modulated by cultural characteristics.

Associations of Handgrip Asymmetry With Impaired Health-Related Quality of Life Among Older Adults in South Korea: A Cross-Sectional Study Using National Survey Data.

This study aimed to examine the associations of handgrip strength (HGS) and asymmetry with health-related quality of life among South Korean older adults. We enrolled 7395 older adults from the Korea National Health and Nutrition Examination Survey. Health-related quality of life was measured using the EuroQol-5 Dimension. Weakness was defined as a HGS of <26 kg for men and <18 kg for women. Handgrip strength symmetry was defined as an HGS ratio of 0.9:1.1, and HGS asymmetry was defined as a ratio outside that range. Data were analyzed using the Rao-Scott χ2, F test, and multivariate logistic regression. Compared with those in the "symmetric HGS and not weak" group, those in the "asymmetric HGS and weak" group had impaired health-related quality of life for all variables among men (odds ratios [ORs] = 1.67-3.75). A greater risk of impaired self-care (SC; odds ratio [OR] = 2.33) and anxiety/depression (AD; OR = 1.40) was observed among women in the "asymmetric HGS and weak" group. Handgrip weakness and asymmetry are associated with impaired health-related quality of life. Handgrip asymmetry can be a clinical marker of health-related quality of life in older adults and must be measured alongside HGS.

Interaction of scapular dyskinesis with hand dominance on three-dimensional scapular kinematics.

INTRODUCTION: This study aimed to evaluate the effect of scapular dyskinesis and its interaction with hand dominance and humerothoracic angles on three-dimensional scapular kinematics in asymptomatic individuals in all planes of arm motion. METHODS: Forty-five asymptomatic participants, seventeen men and twenty-eight women, were separated into two groups: with (n = 22) and without scapular dyskinesis (n = 23) according to the Yes/No classification. Scapular kinematic data of dominant and non-dominant sides in both groups were measured with an electromagnetic tracking device during arm elevation and lowering phases in scapular, frontal and sagittal planes. A linear mixed model of covariance adjusted for age and BMI was used, which included hand dominance (dominant and non-dominant), group (with and without scapular dyskinesis), angles (30°, 60°, 90°, and 120°), and the interaction effect (group × hand dominance × humerothoracic angle). RESULTS: There was a significant interaction effect on scapular anterior tilt and upward rotation in the sagittal plane, and for internal rotation and anterior tilt in the frontal and scapular planes. The effects of hand dominance on three-dimensional scapular kinematics, as increased anterior tilt, internal rotation and upward rotation, were greater in individuals without scapular dyskinesis. CONCLUSION: The effects of dominant side as increased upward rotation, internal rotation, and anterior tilt at higher humerothoracic angles for all planes of arm motion, were greater in individuals without scapular dyskinesis. Our findings may assist the scapular assessment which in individuals without scapular dyskinesis, bilaterally, possible between side differences in the scapular motions may be related to a dominance effect.

Hemispheric asymmetry of chromatic motion perception.

The present study investigated hemispheric symmetry of cortical functions, in terms of the chromatic motion mechanism. A series of experiments examined the visual sensitivities to chromatic and achromatic stimuli with or without motion, presented in either of the two (left or right) visual hemifields. Experiment 1 measured, individually, the subjective isoluminance of red/green stimuli for each visual field. Experiment 2 examined the visual field differences of the detection thresholds for static stimuli with the isoluminant color contrast and achromatic luminance contrast. Subsequent experiments measured contrast thresholds for motion detection (Experiment 3) and motion direction discrimination (Experiment 4) with both chromatic and achromatic stimuli. No visual field differences between thresholds were found in Experiments 1 and 2, whereas in Experiments 3 and 4, thresholds for the chromatic conditions were found to be lower in the left than in the right visual field, suggesting functional lateralization of the early motion mechanism with chromatic information in motion detection and direction discrimination.

Effectiveness of the Semi-Adjustable Articulator Compared to Clinical Examination

ABSTRACT: This work aims to verify the effectiveness of the semi-adjustable articulator (SAA) when compared to a clinical examination of samples in individuals comparing the number of occlusal interferences. The research was carried out at FAESA (Integrated University of São Pedro), in which two independent researchers compared occlusal interferences in protrusion and laterality movements in the clinical examination and in models mounted on a semi-adjustable articulator, with carbon from Baush, in 77 patients who attended to the graduation clinic. Data were tabulated and evaluated by the Mann- Whitney statistical test and data normality was verified by the Kolmogorov-Smirnov test. When analyzing the interference of protrusion on central incisors, it was found that the mean was higher for the SAA on clinical examination. As for the right laterality in the canine guides, it was observed that the clinical examination had a higher interference average in relation to the SAA. The same was true for left laterality, where the mean interference was also higher for the clinical examination. That is, by increasing the values of occlusions in the SAA, the values of occlusions in the clinical examination also increase. As central incisor protrusions between the SAA and clinical examination were moderately positive, there was a strong positive relationship for the right sides and a moderate positive relationship for the left sides. It is concluded that a semi-adjustable articulator is an effective tool for the diagnosis and planning of the dentist, due to its ability to simulate mandibular movements. However, such a tool requires prior knowledge for an ideal assembly for treatment success.

RESUMEN: Este trabajo tuvo como objetivo verificar la efectividad del articulador semi-ajustable (SAA) cuando se compara con un examen clínico de muestras en individuos de acuerdo al número de interferencias oclusales. La investigación se llevó a cabo en FAESA (Universidad Integrada de São Pedro), en la que dos investigadores independientes compararon las interferencias oclusales en los movimientos de protrusión y lateralidad en el examen clínico y en modelos montados en un articulador semiajustable, con carbón de Baush, en 77 pacientes que acudieron a la clínica de graduación. Los datos se tabularon y evaluaron mediante la prueba estadística de Mann-Whitney y la normalidad de los datos se verificó mediante la prueba de Kolmogorov-Smirnov. Al analizar la interferencia de la protrusión en los incisivos centrales, se encontró que la media era mayor para el SAA en el examen clínico. En cuanto a la lateralidad derecha en las guías caninas, se observó que el examen clínico tuvo un promedio de interferencia más alto en relación al SAA. Lo mismo ocurrió con la lateralidad izquierda, donde la interferencia media también fue mayor para el examen clínico. Es decir, al aumentar los valores de oclusiones en el SAA, también aumentan los valores de oclusiones en el examen clínico. Como las protuberancias de los incisivos centrales entre el SAA y el examen clínico fueron moderadamente positivas, hubo una fuerte relación positiva para los lados derechos y una relación positiva moderada para los lados izquierdos. Se concluye que un articulador semi-ajustable es una herramienta eficaz para el diagnóstico y planificación del odontólogo, debido a su capacidad para simular movimientos mandibulares. Sin embargo, tal herramienta requiere conocimientos previos para un montaje ideal para el éxito del tratamiento.

Handgrip strength asymmetry is associated with the risk of neurodegenerative disorders among Chinese older adults.

BACKGROUND: Neurodegenerative disorders, as the irreversible condition, have a long, silent preclinical period. Recognition of early physical signs of neurodegenerative disorders had important practical implications for identifying at-risk population. The aim of this study was to investigate whether handgrip strength (HGS) asymmetry was associated with the incidence of neurodegenerative disorders among Chinese older adults. METHODS: This study used the data of participants aged 60 years and over from three waves (2011-2015) of China Health and Retirement Longitudinal Study. HGS asymmetry was measured with HGS ratio (maximal non-dominant HGS/maximal dominant HGS), with the value less than 0.9 or more than 1.1 considered as HGS asymmetry. Physician-diagnosed neurodegenerative disorders were identified by self-reported or proxy-reported information. Competing risk analysis was conducted to examine the association between HGS asymmetry and incident neurodegenerative disorders, with mortality treated as the competing event. RESULTS: A total of 4925 participants were included in the analysis [mean (SD) age: 68.1(6.68); female: 49.7%]. Eight hundred and eighty-eight (18.0%) participants had low HGS and 2227 (45.2%) had HGS asymmetry. During the 4 years of follow-up, there were 156 cases of neurodegenerative disorders and 422 cases of mortality. The incidence of neurodegenerative disorders was 8.7 per 1000 person-years [95% confidence interval (CI): 7.4-10.2], and the incidence of mortality was 23.5 per 1000 person-years (95% CI: 21.4-25.9). Both the cause-specific model and the Fine-Gray subdistribution hazard model showed that participants with HGS asymmetry had increased hazard of neurodegenerative disorders [hazard ratio (HR) = 1.66, P = 0.002, 95% CI: 1.202-2.297; subdistribution hazard ratio (SHR) = 1.65, P = 0.002, 95% CI: 1.202-2.285]. Low HGS, but not HGS asymmetry, was related to the higher hazard of mortality (HR = 1.61, P < 0.001, 95% CI: 1.297-1.995; SHR = 1.58, P < 0.001, 95% CI: 1.286-1.951). CONCLUSIONS: Handgrip strength asymmetry was associated with the future risk of neurodegenerative disorders among Chinese older adults. Public healthcare providers could consider examining HGS asymmetry along with the maximal HGS as a way to identify those at elevated risk of neurodegenerative disorders.

Normatização do teste de função Manual Jebsen-Taylor para população brasileira / Standardization of the Jebsen-Taylor hand Function test for the brazilian population

O objetivo deste estudo foi apresentar dados normativos para o TFMJT para a população brasileira. Participaram do estudo 360 pessoas, entre 06 e 49 anos, divididas em seis grupos por faixa etária, sendo 178 do sexo masculino e 182 do sexo feminino. Os dados foram apresentados separadamente para as diferentes faixas etárias, para sexo masculino e feminino. Os valores referentes às médias e ao desvio padrão foram calculados para cada uma das sete tarefas, considerando mão dominante e mão não dominante. Observou-se desempenho superior para mão dominante, com diferença significante para a soma das sete tarefas, em ambos os sexos (p=0,001). Os resultados obtidos poderão servir de parâmetros de referência para a população brasileira e contribuir para avaliações quantitativas do desempenho manual em programas de avaliação ou reabilitação do membro superior.

The aim of this study was to present normative data for the JTHF for the Brazilian population. Participated 360 individuals between 06 and 49 years old, divided into six groups by age, being 178 males and 182 females. The data were presented separately for the different age groups, for men and women. Values for means and standard deviation were calculated for each of the seven tasks, considering dominant and non-dominant hands. Superior performance was observed for the dominant hand, with a significant difference for the sum of the seven tasks, in both sexes (p = 0.001). The results obtained is a reference parameter for the Brazilian population and contribute to quantitative assessments of manual performance in programs of assessment or rehabilitation of the upper limb.

Structural asymmetries in normal brain anatomy: A brief overview.

PURPOSE: A fundamental feature in interpreting gross or neuroimaging brain anatomy is reliance on an assumed high degree of morphologic symmetry in bilateral hemispheres. However, the normal brain is not perfectly symmetrical, and subtle inherent structural asymmetries could potentially confound appreciation of pathology-induced asymmetry or how a given brain asymmetry can relate to its function. MATERIAL AND METHODS: We review the literature and provide a brief overview of structural asymmetries in normal brain anatomy. RESULTS: Brain structural asymmetries are either rotational or pure right-left asymmetries, and many are a consequence of unique features linked to the use of human language. Yakovlevian torque is the tendency of the right hemisphere to rotate slightly forward relative to the left, which may make the right frontal lobe bigger and wider, and the left occipital lobe wider and protrude rightward. This makes the left Sylvian fissure longer and flatter, resulting in a larger planum temporale. We also discuss right-left asymmetries in the cortex, white matter structures, deep gray nuclei, and lateral ventricles. Brain asymmetries are not random but result from distinct patterns in structural design that confer evolutionary functional advantages. CONCLUSION: Minor brain asymmetries are important and should be accounted for as they can be connected to function, and like individual variability, are essential for evolution. This overview will help understand structural brain asymmetries for improved diagnostic neuroimaging interpretation, constructing symmetry-based paradigms for automatic localization, segmentation of brain lesions, and as a reference for studies on possible implications of excessive asymmetry and altered laterality in cognitive, neurological, and psychiatric disorders.