Reduction in manual asymmetry and decline in fine manual dexterity in right-handed older adults with mild cognitive impairment.

Research in Parkinson's or Alzheimer's disease suggests that hand function is affected by neurodegenerative diseases. However, little is known about the relationship between hand function and mild cognitive impairment (MCI). Therefore, we conducted a kinematic analysis of unimanual hand movements in MCI patients to answer whether manual asymmetries and manual dexterity are affected or preserved in this condition. Forty-one MCI patients and fifty healthy controls were tested with the Purdue Pegboard test. All participants were right-handed. Kinematic analyses (by hand) were calculated for path length, angle, and linear and angular velocities during reaching, grasping, transport and inserting. Group differences were tested by with factorial MANOVAs and laterality indexes (LI) were assessed. Groups were compared on "Right-Left" hand correlations to identify kinematics that best single-out patients. Kinematics from grasping and inserting were significantly more deteriorated in the MCI group, while outcomes for reaching and transport denoted superior performance. LIs data showed symmetry of movements in the MCI group, during reaching and transport. Comparisons of "Right-Left" hand correlations revealed that kinematics in reaching and transport were more symmetrical in patients. This study showed a deterioration of fine manual dexterity, an enhancement in gross dexterity of upper-limbs, and symmetrical movements in MCI patients.

Test of the auricular surface sex estimation method in fetuses and non-adults under 5 years old from the Lisbon and Granada Reference Collections.

Non-adult sex estimation is an active field of forensic inquiry as morphological variations between males and females are subtle, but observable, even from intrauterine development. The objectives of this study are threefold: to test the validity of the auricular surface method for sex estimation (Int J Osteoarchaeol 27:898-911, 2017) in fetuses and children under the age of 5 years old; to evaluate if health conditions, reported as the cause of death, influence its accuracy; and to detect possible secular trends in sexual dimorphism. One-hundred and ninety-seven skeletal individuals from the Lisbon and Granada Identified Collections were studied. Individuals were divided according to the hormonal peaks (< 0, 0-2, < 2, and 2.1-5 years old), cause, and year of death (before and after 1960). As in previous studies, two ratios (FI/CF and DE/AD) and two qualitative variables (OM and MRS) showed the highest frequencies of correct estimation (0.81-0.86). The correct sex allocations increased when the discriminant function (0.85) and logistic regression (0.86) were applied. Males of the age groups < 0 and 2.1-5 years were all correctly sexed by both formulae, and the same was observed for the female probabilities of adequate allocation. The cause and year of death were identified as variables without statistical significance. It is proposed that this method can be incorporated with confidence into the multifactorial laboratory protocols for non-adult sex estimation from skeletal remains.

What does hand motor function tell us about our aging brain in association with WMH?

BACKGROUND: White matter hyperintensities (WMH) are a common cerebral finding in older people. WMH are usually asymptomatic, but excessive WMH are associated with cognitive decline and dementia. WMH are also among the neurological findings most consistently associated with declining motor performance in healthy ageing. AIMS: To determine if WMH load is associated with simple and complex motor movements in dominant and non-dominant hands in cognitively intact older subjects. METHODS: Hand motor performance was assessed with the Purdue Pegboard and Finger-tapping tests on 44 healthy right-handed participants, mean age 70.9 years (range 59-84 years). Participants also underwent magnetic resonance (MR) imaging, which were used to quantify WMH volume. The effect of WMH on the motor parameters was assessed via mediation analyses. RESULTS: WMH load increased significantly with age, while the motor scores decreased significantly with age. WMH load mediated only the relationship between age and left-hand pegboard scores. DISCUSSION: WMH mediated only the more complex Purdue Pegboard task for the non-dominant hand. This is likely because complex movements in the non-dominant hand recruit a larger cerebral network, which is more vulnerable to WMH. CONCLUSIONS: Complex hand movements in the non-dominant hand are mediated by WMH. Subtle loss of motor movements of non-dominant hand might predict future excessive white matter atrophy.

Evaluation of the auricular surface method for non-adult sex estimation on the Lisbon documented collection.

OBJECTIVES: Sex is usually not estimated in skeletonized non-adult individuals because sexual dimorphism is considered minimal before puberty. In 2017, a new approach based on the shape of the auricular surface was proposed, showing that this anatomic area of the ilium is dimorphic. This study tests the reproducibility and evaluates the accuracy of the method in a bigger sample. MATERIALS AND METHODS: Thirty males and 31 females from the Lisbon Collection (1 day-18 years old) were analyzed by two researchers, one experienced, and the other without previous knowledge of the method. The sample was divided into three groups according to prepubertal and pubertal hormonal peaks (<2, 0-12, and 13-18 years old). Two metric variables (DE/AD and FI/CF ratios), two morphological features (Overall Morphology, OM and Morphology of the Retroauricular End of the Superior Demiface, MRS), and two formulae were tested based on the adequate results obtained in the original article. RESULTS: Data shows a low interobserver error (ICC > 0.92; K > 0.74). Morphological features provide better results than the metrics (DE/AD = 77.05%; FI/CF = 73.77%; OM = 80.33%; MRS = 85.24%). The discriminant function correctly classified 86.66% of the males and the logistic regression, 83.33%. The method was equally reliable in 0-12 and 13-18 years-old age groups and more accurate in males. The accuracy of most of the variables reached 100% for males under 2 years-old, and the probabilities were higher than for older individuals. The percentages of correct estimations are not influenced by the age, year, and cause of death. DISCUSSION: Despite the relatively small sample size, this study confirms the usefulness of the auricular surface for non-adult sexual estimation, especially for those younger than 2 years old. Additional validation tests in documented individuals from other geographic regions are suggested.

Manual dexterity in young and healthy older adults. 2. Association with cognitive abilities.

Currently, little is known about the cognitive constraints underlying manual dexterity decline in aging. Here, we assessed the relationship between cognitive function and dexterity in 45 young and 55 healthy older adults. Effects of gender on the cognition-dexterity association were also explored. Cognitive assessment comprised neuropsychological tests of executive function, working memory, attention, and memory. Dexterity assessment included evaluation of movement times and kinematics during performance of unimanual and bimanual tasks of the Purdue Pegboard Test. Cognitive and dexterity group differences were established. Thereafter, regression analyses showed that executive function best predicted movement times and to some extent path lengths for the left hand in the older group. No gender differences were found in older participants. The findings confirm the involvement of executive function in manual dexterity in aging and suggest that movement times and path length may be useful parameters to assess the cognition-dexterity association in older adults.

Manual dexterity in young and healthy older adults. 1. Age- and gender-related differences in unimanual and bimanual performance.

This study aimed to better characterize age-related differences in dexterity by using an integrative approach where movement times and kinematics were measured for both hands. Forty-five young (age 19-31) and 55 healthy older adults (age 60-88) were evaluated during unimanual and bimanual performance of the Purdue Pegboard Test. Gender effects were also assessed. From video-recorded data, movement times and kinematics were obtained for reaching, grasping, transport, and inserting. Results showed that older adults had longer movement times for grasping and inserting with the right hand, and across all movements with the left hand. Kinematic differences were found in path length, linear, and angular velocity. The patterns of slowing were similar in unimanual and bimanual tasks. Gender effects showed more slowing in older males than older females. Age differences in dexterity not only comprise slowing of movements but also kinematic alterations. The importance of gender in hand function was demonstrated.

Forensic International Dental Database (FIDBv2) for adult age-at-death estimation in multiple forensic contexts: Strengthening the operationalization of the Lamendin criteria in a global scope model.

The aim of this study is to validate the FIDBv2 online procedure for adult age-at-death estimation using root dentine translucency (RDT) and periodontal retraction (PR) of single-rooted teeth in a worldwide sample. The sample includes 4810 teeth of 2559 individuals from 16 countries of America, Europe and Asia. Bias and inaccuracy between documented (DA) and estimated ages (EA) were calculated. Pearson and Intraclass Correlation Coefficients were computed to assess the strength of agreement between pairs of data, while Kolmogorov-Smirnov Z was used to evaluate the statistical significance of the differences. The percentages of correctly estimated cases within different age ranges were obtained to find trends in the reliability of the results. Most of the biases (-4.61-1.31 years) and inaccuracies (4.81-9.72 years) are low. The dispersion of EA increases with age and almost all the DA-EA correlations are above 0.75. DA-RDT and DA-PR correlations are positive, most of the former being high (0.74-0.91), and the latter being low (0.11-0.54). The highest percentages of correct estimations are identified for the ±7.5 and ±10 years ranges, and most comparisons of bias and inaccuracy between countries are non-significant. The high correlations between DA and EA suggest that the method is robust and reliable for a global application. Mean errors are low, with the best results found in the 30-69-year-old cohort. This research supports that the method is effective and accurate for age estimation in forensic contexts worldwide, thus reaffirming it is a generalizable procedure locally and internationally.

Effects of verbal tasks with varying difficulty on real-time respiratory airflow during speech generation in healthy young adults.

Objective: Respiratory function is linked to sensory, affective, and cognitive processes and it is affected by environmental constraints such as cognitive demands. It is suggested that specific cognitive processes, such as working memory or executive functioning, may impact breathing. In turn, various lines of research have suggested a link between peak expiratory airflow (PEF) and cognitive function. However, there is scarce experimental support to the above assertions, especially regarding spoken language. Therefore, the present investigation aims to evaluate whether breathing varies as a function of performing verbal naming tasks with different difficulty levels. Methods: Thirty healthy young adults, (age M = 25.37 years), participated in the study. Participants were required to perform aloud five verbal tasks ranged in order of difficulty: Reading single words, reading a text passage, object naming, semantic and phonemic fluency. A pneumotachograph mask was employed to acquire simultaneously the verbal responses, and three airflow parameters: Duration, peak, and volume at both stages of the respiratory cycle (i.e., inspiration/expiration). Data were analyzed with one-way repeated measures MANOVA. Results: No significant differences were found between reading single words and object naming. In comparison, distinctive airflow requirements were found for reading a text passage, which were proportionally related to number of pronounced words. Though, the main finding of the study concerns the data on verbal fluency tasks, which not only entailed higher inhaled airflow resources but also a significant PEF. Conclusion: Our data demonstrated that the most difficult tasks, namely semantic and phonemic verbal fluencies, relying on semantic search, executive function, and fast lexical retrieval of words were those requiring important amount of inhaled airflow and displaying a high peak expiratory airflow. The present findings demonstrated for the first time a direct association between complex verbal tasks and PEF. Inconclusive data related to object naming and reading single words are discussed in light of the methodological challenges inherent to the assessment of speech breathing and cognition in this line of investigation.

Methods for sex estimation of prepubertal individuals (< 12 years old): bibliographic review and future directions.

Sex estimation is essential in both bioarchaeological and forensic research. Based on bibliographical research, this study aims to systematize and compare the existing methods and glance at the future on this research topic. The survey in Web of Science and Google Scholar revealed 37 papers describing the generation of original procedures, and 25 validation studies. The results show that the pelvis, namely the ilium, is the most analyzed anatomical region, followed by the deciduous teeth, the cranium, the mandible, and the long bones. The morphometric approaches are addressed in greater proportion, both as original methods (n = 19) or validations (n = 24). Only one of the 19 approaches that require expensive equipment (conventional radiology, computer tomography, geometric morphometrics and 3D modelling) was tested. Most of them were generated during the 21st century; however, 24 have not been tested yet. Comparing all the methods tested, the percentages of correctly estimated cases are always lower in validation studies. It is suggested that the most promising ones be tested in documented samples by a group of researchers. Thus, the interobserver error would be evaluated and may also lead to new methodological proposals and refinements.

Root dentin translucency and age at death estimation in adults using single rooted teeth: Update of the Forensic International Dental Database.

Since the publication of Lamendin's age estimation technique, the root dentin translucency has received increasing attention as an important indicator of age. Recently, Parra and colleagues presented the Forensic International Dental Database (FIDB), a proposal to estimate age at death in adults based on Bayes theorem by applying the criteria of Lamendin's technique. The present study aims to update the procedure and to evaluate a new version of the method (named FIDBv2) using two control samples from Colombia and Greece. The performance of this new version was acceptable and suggests that the method is suitable for age at death estimation in adult individuals from different forensic contexts. The best approximations to chronological age were obtained for individuals between 30 and 60 years old, with errors less than 10 years. The age estimations calculated on control samples suggest the adequate performance of FIDBv2 on individuals from varied populations. It can be stated that the FIDBv2 constitutes a solid alternative to be used in contexts where no additional data are available. Here we reinforce the initial idea that this model for estimating age at death in adults may be generalizable to any forensic context in the world.

Adult age-at-death estimation using the first rib: A simple probabilistic approach.

Age-at-death estimation is a difficult task in fragmented or incomplete contexts. The generation and testing of methods are needed to identify their potential application in different types of osteological samples. This paper proposes a new method for age estimation using the first rib. Four hundred and fifteen individuals from the Coimbra Identified Skeletal Collections (Portugal) were studied; the sample was divided in two groups (reference and test samples), used to develop the procedure and to evaluate its reliability. The three rib joints and two variables (surface texture and topography, and periarticular margins and subsidence of the surface) were recorded. Statistical analyses were performed to test the procedure reproducibility, and side and sex variations. Posterior probabilities were calculated following Bayesian statistics and used to estimate the most likely age-at-death in the test sample. The results show the reproducibility of the method is adequate, left and right ribs can be indistinctly recorded, and both sexes show similar change patterns. The costal face and the head epiphyseal region offered satisfactory results and the percentages of correct estimations are greater for younger individuals, decreasing as ages-at-death are higher. This method is more effective among individuals in the 20-50 years cohort; nevertheless, it also offered satisfactory estimates in older ones. Overestimations in individuals younger than 40 years and underestimations in individuals older than 75 years were identified. In conclusion, the first rib offer adequate estimates when a basic probabilistic approach is chosen. Whenever possible, this proposal must be included in a multifactorial perspective with other age markers.

Age-related differences in self-report and objective measures of cognitive function in older patients prior to chemotherapy.

AIM: Evaluate for differences in demographic and clinical characteristics and subjective and objective measures of cognitive function (CF) between younger older adults (YOA, 60-69 years) and older adults (OA, ≥70 years). DESIGN: Cross-sectional. METHODS: Older oncology patients (n = 139) completed subjective (Attentional Function Index, European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC) CF scale) and objective (Montreal Cognitive Assessment, Trail Making Test (TMT) A & B) measures of CF prior to chemotherapy. Data were analyzed using parametric and nonparametric tests. RESULTS: No differences were found between the two groups for any of the subjective or objective CF measures, except that OA patients had higher TMT B scores. Compared with the general population, OAs had significantly higher EORTC CF scores and YOAs had significantly worse scores for all of the objective tests. Clinically meaningful difference between group differences was found for the TMT B test.

Differential contribution of cognitive and psychomotor functions to the age-related slowing of speech production.

Healthy elderly adults are slower to initiate and produce speech. However, the sources of the slowing remain poorly understood. The present study evaluates to which extent psychomotor and cognitive changes influence age-related slowing in speech generation. Four verbal tasks varying in degree of difficulty and cognitive demands were used to evaluate 30 young and 30 healthy elderly. Speed of word production was measured by reaction times and pronunciation durations. Stroop test and Digits backwards were used as cognitive predictors while the Purdue Pegboard and Finger Tapping were used as psychomotor predictors. The relative contribution of cognitive and psychomotor functioning was evaluated by hierarchical regression analyses and based on the processing speed hypothesis. Results showed that Vocabulary and psychomotor execution significantly explained a portion of the variance in RTs depending on type of verbal task. These variables explained 36% of the total variance in reading, 26% in naming, 31% in phonemic fluency and 47% in semantic fluency. Also, Vocabulary and psychomotor functions strongly predicted pronunciation speed. Conversely, tests related to executive functions and working memory were not significant predictors. These data demonstrate the importance of the interplay between Vocabulary and psychomotor decline on speed of language production among healthy elderly adults.

Adult sex estimation from the minimum supero-inferior femoral neck diameter in a contemporary osteological sample from Buenos Aires, Argentina.

Sex estimation of adult skeletons is an important step in forensic analysis. Although the femur has been metrically studied for sex assessment around the world, very limited information is actually available on modern populations of Argentina. In this paper, the estimation of sex based on the metric evaluation of the supero-inferior femoral neck diameter (SID) in a reference osteological collection from the contemporary Chacarita Cemetery of Buenos Aires City (Argentina), is evaluated. Protocols generated using SID in other three reference skeletal samples are also tested on this collection. One hundred and sixty-four individuals of both sexes and between 24 and 96 years old are analyzed. Inter and intra observer errors suggest that the replicability of the procedure is adequate. The sectioning point calculated from the direct measurements is 30.86 mm and results show a high degree of dimorphism. The proportions of correct sex discrimination and the likelihoods of correct allocation obtained with the direct measurements, along with the results of a discriminant function, a binary logistic regression and a Bayesian approach, are all higher than 0.85 (0.85-0.93 for females, 0.88-0.91 for males). When the formulae from other samples are used in the Chacarita Collection, the percentages of correct estimations range between 72.41% and 81.03% for females and between 80.46% and 88.50% for males, while the likelihoods are between 0.73 and 0.81 for females and between 0.79 and 0.82 for males. As the values for the estimations obtained using the statistical procedures generated in the present research are higher than those available for other collections, the method is more adequate to use in the analysis of contemporary skeletal remains from Buenos Aires and surrounding areas. The trends identified highlight the importance of population-specific metric methodologies in forensic contexts and deserve future testing in contemporary samples from neighbouring regions.

Maxillary incisor internal root anatomy evaluated by cone-beam computed tomography in a population of the Autonomous City of Buenos Aires, Argentina.

In the field of anthropology, discrete traits are considered as minimal epigenetic variations. However, they can elicit complications in endodontic therapy. Thorough understanding of root canal morphology is essential to achieving predictable results in endodontic practice, and may be attained by using cone-beam computed tomography (CBCT) scans. The aim of the present study was to research the internal root anatomy of maxillary central and lateral incisors in vivo and quantify its variation in a population of the Autonomous City of Buenos Aires, Argentina. A total 697 CBCT scans from a pre-existing database were observed, and the configuration type for each tooth was determined according to Vertucci's classification. The data were described by absolute frequencies and percentages with 95% confidence intervals (CI). The CI was estimated by the Wilson Score method. Chi-square test (χ2) was used for comparing frequencies, with a 5% significance level. 238 CBCT scans met the inclusion criteria, resulting in 761 teeth assessed. Vertucci Type I configuration was observed in 760 teeth (99.9%) and the Type II was found in only one tooth (0.1%), in which the anatomy was compatible with dens in dente. When differences were analyzed according to sex, all the teeth in all women had Vertucci Type I configuration. In men, all maxillary central incisors were Vertucci Type I. Of 151 maxillary lateral incisors, 150 had Vertucci Type I configuration (99.3%) and 1 had Type II (0.7%). Conclusions: Maxillary incisor internal root anatomy prevalence was estimated from CBCT scans for the first time in an Argentine population. 99.9% of the sample presented Vertucci Type I configuration, and 0.1% had Vertucci Type II configuration. The clinical finding of maxillary incisors with anatomical complexity should be considered as a possibility in endodontic practice.

En el ámbito de la antropología, los rasgos discretos son considerados variaciones epigenéticas mínimas, pero pueden traer complicaciones en la terapia endodóntica. Comprender la morfología del conducto radicular es fundamental para lograr resultados predecibles en la práctica endodóntica, y esto puede lograrse mediante el uso de la tomografía cone-beam (CBCT). El objetivo de este trabajo fue investigar de manera in vivo la anatomía radicular interna de incisivos centrales y laterales superiores, y cuantificar su variación en una población de la Ciudad Autónoma de Buenos Aires, Argentina. 697 CBCTs de una base de datos preexistente fueron analizadas, y se consignó para cada pieza el tipo de configuración basada en la clasificación de Vertucci. Los datos se describieron mediante frecuencias absolutas y porcentajes con intervalos de confianza al 95% (IC95). Los IC95 fueron estimados mediante el método score de Wilson. Para la comparación de frecuencias se utilizó la prueba de Chi-cuadrado (χ2), con un nivel de significación de 5%. 238 CBCTs cumplieron con los criterios de inclusión, resultando en 761 piezas evaluadas. Se encontró un Vertucci tipo I en 760 piezas (99,9%) y se halló Vertucci tipo II en una sola pieza dentaria (0,1%), que mostraba anatomía compatible con dens in dente. Diferenciando por sexos, todas las mujeres para todas las piezas mostraron Vertucci tipo I. Los varones en sus incisivos centrales superiores poseían Vertucci tipo I en todas las piezas, y de los 151 incisivos laterales superiores, 150 mostraron tipo I de Vertucci (99,3%) y 1, tipo II (0,7%). Conclusión: La prevalencia de anatomía dentaria interna fue estimada por primera vez en una población argentina mediante CBCTs. El 99,9% de la muestra presentó un Vertucci tipo I, y el 0,1% un Vertucci tipo II. La aparición clínica de incisivos superiores con complejidad anatómica debe ser considerada posible en la práctica endodóntica.

Assessing a Sensory-Motor-Cognition Triad in Amnestic Mild Cognitive Impairment With Dichotic Listening While Walking: A Dual-Task Paradigm.

A contemporary topic in aging research relates to the significance of cognitive changes proper to mild cognitive impairment (MCI) to higher risk of falls and gait deteriorations. The present study addresses this question in the amnestic type of MCI (aMCI) by examining a triad of interrelated comorbidities occurring in the MCI condition: attentional impairments, hearing loss and gait disturbances. To this end, we applied a dichotic listening (DL) test during over-ground walking. DL assesses spontaneous and lateralized auditory attention in three conditions (i.e., free report or Non-forced (NF), Forced-Right (FR) ear and Forced-Left (FL) ear). Earlier reports suggest that this dual-task paradigm evoke asymmetric gait effects on healthy controls, which are moderated by degree of hearing loss. Therefore, the aim of the present study was to evaluate the effects of DL on bilateral (data from both limbs) and lateralized (each limb separately) gait outcomes in a group of forty-three aMCI participants (mean = 71.19) and fifty-two healthy older controls (mean = 70.90) by using hearing loss as a covariate in all analyses. Results showed the aMCI group presented overall compromised gait parameters, especially higher gait variability in all DL conditions during lateralized attentional control. These findings were observed bilaterally, and no lateralized effects on gait were observed. Only after controlling for hearing acuity, gait asymmetries on step length variability emerged almost exclusively in healthy controls. It was concluded that hearing loss in the aMCI group together with higher attentional impairments preclude aMCI individuals to properly execute DL and therefore, they do not display gait asymmetries. The present data demonstrate that varied demands on attentional control dependent on hearing acuity affects gait negatively in healthy older adults and aMCI individuals in very different ways. The appearance of asymmetric effects seems to be a perturbation related to normal aging, while the lack of asymmetries but exaggerated gait variability characterizes aMCI. The present findings show the intricate interplay of sensory, cognitive, and motor deteriorations in different group of older adults, which stresses the need of addressing co-occurring comorbidities behind gait perturbations in individuals prone to develop a dementia state.

Evaluation of Error Production in Animal Fluency and Its Relationship to Frontal Tracts in Normal Aging and Mild Alzheimer's Disease: A Combined LDA and Time-Course Analysis Investigation.

Semantic verbal fluency (VF), assessed by animal category, is a task widely used for early detection of dementia. A feature not regularly assessed is the occurrence of errors such as perseverations and intrusions. So far, no investigation has analyzed the how and when of error occurrence during semantic VF in aging populations, together with their possible neural correlates. The present study aims to address the issue using a combined methodology based on latent Dirichlet allocation (LDA) analysis for word classification together with a time-course analysis identifying exact time of errors' occurrence. LDA is a modeling technique that discloses hidden semantic structures based on a given corpus of documents. We evaluated a sample of 66 participants divided into a healthy young group (n = 24), healthy older adult group (n = 23), and group of patients with mild Alzheimer's disease (AD) (n = 19). We performed DTI analyses to evaluate the white matter integrity of three frontal tracts purportedly underlying error commission: anterior thalamic radiation, frontal aslant tract, and uncinate fasciculus. Contrasts of DTI metrics were performed on the older groups who were further classified into high-error rate and low-error rate subgroups. Results demonstrated a unique deployment of error commission in the patient group characterized by high incidence of intrusions in the first 15 s and higher rate of perseverations toward the end of the trial. Healthy groups predominantly showed very low incidence of perseverations. The DTI analyses revealed that the patients with AD committing high-error rate presented significantly more degenerated frontal tracts in the left hemisphere. Thus, our findings demonstrated that the appearance of intrusions, together with left hemisphere degeneration of frontal tracts, is a pathognomic trait of mild AD. Furthermore, our data suggest that the error commission of patients with AD arises from executive and working memory impairments related partly to deteriorated left frontal tracts.

Effects of dichotic listening on gait domains of healthy older adults during dual-tasking: An exploratory observational study.

BACKGROUND: Identification of the cognitive mechanisms behind gait changes in aging is a prime endeavor in gerontology and geriatrics. For this reason, we have implemented a new dual-task paradigm where an auditory attentional task is performed during over-ground walking. Dichotic listening assesses spontaneous attention and voluntary attention directed to right and left-ear. The uniqueness of dichotic listening relies on its requirements that vary in difficulty and recruitment of resources from whole brain to one brain hemisphere. When used in dual-tasking, asymmetric effects on certain gait parameters have been reported. OBJECTIVES: The present study aims to acquire a more global understanding on how dichotic listening affects gait domains. Specifically, we aimed to understand how spontaneous vs lateralized auditory attention altered the Principal Component Analysis (PCA) structure of gait in healthy older adults. METHODS: Seventy-eight healthy older adults (mean age: 71.1 years; 44 women and 34 men) underwent the Bergen dichotic listening test while walking. As this study only focuses on the effects of the cognitive task on gait, only dual-task costs for gait were calculated and entered into the PCA analyses. We explored the PCA structure for the effects on bilateral gait parameters (i.e., both limbs together) as well as on lateralized gait parameters (i.e, separate parameters by limb). We first established gait domains during single-task walking. Then, dual-task cost scores for gait were entered in a series of PCAs. RESULTS: Results from the PCAs for bilateral gait parameters showed limited alterations on gait structure. In contrast, PCAs for lateralized data demonstrated modifications of the gait structure during dichotic listening. The PCAs corresponding for all dichotic listening conditions showed different factor solutions ranging between 4 and 6 factors that explained between 73.8% to 80% of the total variance. As a whole, all conditions had an impact on "pace", "pace variability" and "base of support variability" domains. In the spontaneous attention condition, a six-factor solution explaining 78.3% of the variance showed asymmetrical disruptions on the PCA structure. When attention was focused to right-ear, a five-factor solution explaining 89% of the variance and similar to baseline was found. When attention was directed to left-ear, a four-factor solution explaining 73.8% of the variance was found with symmetrical impact on all factors. CONCLUSIONS: These findings demonstrate for the first time that specific facets of attentional control affects gait domains both symmetrically and asymmetrically in healthy older adults.

Age-at-death estimation in adults using three forensic methodologies: A Lamendin's technique approach for Latin American context and the extension of a forensic international dental database.

In forensic science, the information that teeth provide to the age estimation process is very important. In adults, one of the most widely used indicators of skeletal age is the Root Dentin Translucency (RDT), mainly through the Lamendin technique, which is used in various Latin American contexts. Recently, Parra et al. (2020) have developed a Bayesian regression model using the Lamendin technique to establish standardized criteria for estimating age-at-death in adults in various forensic contexts. In this study, we evaluate the applicability of this proposal together with the proposal by Lamendin et al. (1992) and Prince and Ubelaker (2002) in Latin American contexts. A sample of single-rooted teeth belonging to 805 individuals from six Latin American countries was used. The results of the three proposals considered were analyzed taking into account factors such as age, sex, origin, and the tooth surface on which the variables were surveyed. Of the factors that would affect the estimates, it was found that the age of the individuals had the greatest influence. However, it was confirmed that the sex and surface of the teeth on which the measurements were taken did not influence the final result. On the other hand, as we expected, the application of the analyzed proposals would also be possible in other forensic contexts, as shown by the results obtained according to the origin. This research expands the FIDB with more information on Latino contexts.

Dichotic listening while walking: A dual-task paradigm examining gait asymmetries in healthy older and younger adults.

Dual-task studies have employed various cognitive tasks to evaluate the relationship between gait and cognition. Most of these tests are not specific to a single cognitive ability or sensory modality and have limited ecological validity. In this study, we employed a dual-task paradigm using Dichotic Listening (DL) as concomitant cognitive task to walking. We argue that DL is a robust task to unravel the gait-cognition link in different healthy populations of different age groups. Thirty-six healthy older adults (Mean = 67.11) and forty younger adults (Mean = 22.75) participated in the study. DL consists of three conditions where spontaneous attention and attention directed to right or left-ear are tested while walking. We calculated dual-task costs (DTCs) and percent of baseline values for three spatio-temporal gait parameters as compared to single-walking during three DL conditions. Results showed that both groups had larger DTCs on gait during volitional control of attention, i.e., directing attention to one specific ear. Group differences were present across all DL conditions where older adults reported consistently less correct stimuli than younger participants. Similar findings were observed in the neuropsychological battery where older participants showed restricted abilities for executive functioning and processing speed. However, the main finding of this investigation was that younger adults exhibited unique adjustments in step length variability as shown by changes in DTCs and percent of baseline values. Particularly, an asymmetric effect was observed on the young group when attending right-ear stimuli. We interpreted this gait asymmetry as a compensatory outcome in the younger participants due to their optimal perceptual and motor abilities, which allow them to cope suitably with the dual-task situation. Many studies suggest that gait asymmetries are indicators of pathology, the present data demonstrate that gait asymmetries arise under specific constraints in healthy people as an adaptation to task requirements.