Research Interests:
Background During the aging process, cognitive functions and performance of the muscular and neural system show signs of decline, thus making the elderly more susceptible to disease and death. These alterations, which occur with advanced... more
Background During the aging process, cognitive functions and performance of the muscular and neural system show signs of decline, thus making the elderly more susceptible to disease and death. These alterations, which occur with advanced age, affect functional performance in both the lower and upper members, and consequently human motor functions. Objective measurements are important tools to help understand and characterize the dysfunctions and limitations that occur due to neuromuscular changes related to advancing age. Therefore, the objective of this study is to attest to the difference between groups of young and old individuals through manual movements and whether the combination of features can produce a linear correlation concerning the different age groups. Methods This study counted on 99 participants, these were divided into 8 groups, which were grouped by age. The data collection was performed using inertial sensors (positioned on the back of the hand and on the back of ...
Research Interests:
Research Interests:
The objective of this work was to use the autocorrelation function to assess the fine motor performance of a healthy control group (CG) and people with Parkinson's disease (PD), whose fluctuations caused by the disease compromise... more
The objective of this work was to use the autocorrelation function to assess the fine motor performance of a healthy control group (CG) and people with Parkinson's disease (PD), whose fluctuations caused by the disease compromise motor skills, performed mainly by the hands and fingers essential for daily activities such as dressing, carrying objects and taking care of personal hygiene. For this, accelerometer signals were collected while the volunteers drew a sinusoidal pattern. The correlogram was estimated and two features were calculated from it: (i) the normalized area under the curve (𝑨𝒖𝑪); (ii) the difference between matching peaks and valleys from the reference and estimated correlograms (𝒗𝒎𝒎). These features allowed for the discrimination between drawing patterns of CG (𝒗𝒎𝒎= 0.154±0.063, 𝑨𝒖𝑪 = 0.204±0.040) and PD (𝒗𝒎𝒎 = 0.239±0.085, 𝑨𝒖𝑪 = 0.179±0.033) groups. Following the verification of normality (Shapiro-Wilk, p > 0.05), the t-test was applied to confirm the significant differences between groups (p < 0.05). The Cohen's d effect size (p < 0.05) was medium (0.730) for 𝑨𝒖𝑪 and large (1.252) for 𝒗𝒎𝒎. This further confirms the differences between the features extracted from the groups. Therefore, the features 𝑨𝒖𝑪 and 𝒗𝒎𝒎 estimated from the autocorrelation function are effective for the assessment of the motor performance of healthy individuals and people with PD.
Research Interests:
A Doença de Parkinson (DP) é uma afecção do Sistema Nervoso Central (SNC) que provoca a perda progressiva de neurônios produtores de dopamina da substância negra, o que reduz a atividade das áreas motoras do córtex cerebral. Os... more
A Doença de Parkinson (DP) é uma afecção do Sistema Nervoso Central (SNC) que provoca a perda progressiva de neurônios produtores de dopamina da substância negra, o que reduz a atividade das áreas motoras do córtex cerebral. Os comprometimentos manifestam-se inicialmente de forma motora, como bradicinesia, rigidez muscular, tremor em repouso e instabilidade postural. A evolução da DP também gera complicações secundárias e um dos sintomas secundários mais severos é o congelamento da marcha, do inglês, freezing of the gait (FOG). O FOG é uma desordem única na qual os indivíduos não conseguem continuar ou iniciar o movimento de caminhar. O presente trabalho tem como objetivo reunir informações para descrever e entender o FOG e agrupar as hipóteses acerca desse sintoma. A busca na literatura foi realizada em bases de dados robustas, considerando artigos em inglês e português e após a triagem foram considerados 30 artigos. O trabalho reune definições, estudos, gatilhos e hipóteses sobre o tema e também propõe trabalhos futuros.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Deep brain stimulation (DBS) is an effective treatment of several types of neurological conditions, including Parkinson’s disease, essential tremor, dystonia, and epilepsy. Despite technological progress in the past 10 years, the number... more
Deep brain stimulation (DBS) is an effective treatment of several types of neurological conditions, including Parkinson’s disease, essential tremor, dystonia, and epilepsy. Despite technological progress in the past 10 years, the number of studies reporting side effects of DBS has increased, mainly due to hardware failures. This review investigated studies published between 2017 and 2021 to identify the prevalence of distinct types of hardware failures related to DBS. In total, fifteen studies were selected for the estimate of the prevalence of five distinct types of hardware failures: high impedance, fracture or failure of the lead or other parts of the implant, skin erosion and infection, lead malposition or migration, and implantable pulse generator (IPG) malfunction. The quality evaluation of the studies suggests a need to report results including populations from distinct regions of the world so that results can be generalized. The objective analysis of the prevalence of hardware failures showed that skin erosion and infection presented the highest prevalence in relation to other hardware failures. Despite the sophistication of the surgical technique of DBS over time, there is a considerable complication rate, about 7 per 100 individuals (prevalence=6.67%,CI=[2.26%,12.49%]\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{prevalence}=6.67\%, CI = [2.26\%,12.49\%]$$\end{document}, in which CI is the confidence interval). Future research can also include correlation analysis with the aim of understanding the correlation between distinct hardware failures and variables such as gender, type of disorder, and age.
Research Interests:
Research Interests:
Research Interests:
Hospital furniture is the furniture used as support to specific services at the hospital. The quality and the conservation state of this furniture influence on security and performance of the health professionals and the patient’s... more
Hospital furniture is the furniture used as support to specific services at the hospital. The quality and the conservation state of this furniture influence on security and performance of the health professionals and the patient’s recover. Thereby, this study carries on an evaluation of the quality and the conservational state of the furniture used at general inpatient rooms from different inpatient units of three hospitals, aiming to detect the factors that can influence on patient care or compromising the attendance. The furniture included in this study are hospital bed, meal table, companion armchair, locker, bedside table, serum support, and two-step stairs. Two methods were used for this evaluation: checklist and questionnaire. This research was approved for the Ethics committee with de CAAE: 65008617.1.0000.5152 and was fullfilled on Inpatient Units of Health Care Facility (HCF) Public, Private and maintained by a Non-governmental Organization (NGO), for comparison. The Private HCF got mostly positive results. Followed by the HCF maintained by a NGO and, for last, the Public HCF. The characteristics of demand, economy and exposure that influence these results were discussed.
Research Interests:
Research Interests:
This work consists of a systematic review that aims identify and illustrate the various limitations that health systems currently face regarding the metrological system reliability of medical equipment. Studies have been made in the... more
This work consists of a systematic review that aims identify and illustrate the various limitations that health systems currently face regarding the metrological system reliability of medical equipment. Studies have been made in the search for scientific articles in databases chosen, and after the application of the criteria for inclusion and exclusion for articles, obtained 6 publications, that represented the base of the construction of this work. The metrological reliability of medical equipment is extremely important in health services, as it ensures, among other things, the safety of diagnostics and treatments. It was possible to observe that this is a matter of very little presence in the daily lives of the professionals of the health area, pointing to the need for evaluation of the reliability in most cases presented.
Research Interests:
Research Interests: Psychology and Athletes
The abdominal muscles are extremely important because they are directly involved in the functions of support, containment of viscera, and help in the process of expiration, defecation, urination, vomiting, and also at the time of... more
The abdominal muscles are extremely important because they are directly involved in the functions of support, containment of viscera, and help in the process of expiration, defecation, urination, vomiting, and also at the time of childbirth. Many exercises and equipment are used to strengthen the abdominal muscles, and the workouts are proposed for a variety of purposes, such as preventing and rehabilitating low back pain, improving sports performance, achieving aesthetic standards, among others. Exercises that potentiate the electromyographic activity promote a greater recruitment of muscle fibers and are more effective to improve or maintain of the force. The electromyographic activity analysis allows us to reflect on the quality of the exercises proposed, consequently, to choose and order the exercises properly in a training session. Our systematic review protocol will developed following the reporting items for the systematic review. To identify relevant studies, we sought artic...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Parkinson’s disease (PD), whose cardinal signs are tremor, rigidity, bradykinesia, and postural instability, gradually reduces the quality of life of the patient, making early diagnosis and follow-up of the disorder essential. This study... more
Parkinson’s disease (PD), whose cardinal signs are tremor, rigidity, bradykinesia, and postural instability, gradually reduces the quality of life of the patient, making early diagnosis and follow-up of the disorder essential. This study aims to contribute to the objective evaluation of tremor in PD by introducing and assessing histograms of oriented gradients (HOG) to the analysis of handwriting sinusoidal and spiral patterns. These patterns were digitized and collected from handwritten drawings of people with PD ( n = 20) and control healthy individuals ( n = 20). The HOG descriptor was employed to represent relevant information from the data classified by three distinct machine-learning methods (random forest, k-nearest neighbor, support vector machine) and a deep learning method (convolutional neural network) to identify tremor in participants with PD automatically. The HOG descriptor allowed for the highest discriminating rates (accuracy 83.1%, sensitivity 85.4%, specificity 80.8%, area under the curve 91%) on the test set of sinusoidal patterns by using the one-dimensional convolutional neural network. In addition, ANOVA and Tukey analysis showed that the sinusoidal drawing is more appropriate than the spiral pattern, which is the most common drawing used for tremor detection. This research introduces a novel and alternative way of quantifying and evaluating tremor by means of handwritten drawings. Graphical abstract
Research Interests:
Research Interests:
In late stages of Parkinson's Disease (PD) or Essential Tremor (ET), surgical treatments, such as Deep Brain Stimulation (DBS), are promising. However, conventional DBS devices are open-loop systems in which the stimulation intensity... more
In late stages of Parkinson's Disease (PD) or Essential Tremor (ET), surgical treatments, such as Deep Brain Stimulation (DBS), are promising. However, conventional DBS devices are open-loop systems in which the stimulation intensity is constant regardless of the dynamic behavior of motor manifestations. In this sense the seek to objective strategies that can assess the efficacy of DBS is relevant for the development of precise medicine, promoting the implementation of closed-loop DBS. This study proposes the use of individualized Gaussian models to evaluate the motor signs of people with PD and ET considering DBS in ON and OFF states. Inertial data were collected from the left and right hands and forearms of the participants. After data preprocessing, amplitude and variability-based features were extracted to estimate specific Gaussian models for each individual. An objective metric that is sensitive to the distance of models from DBS in ON and OFF states was proposed. The specific Gaussian models allowed for the estimate of tremor probability in the DBS states. The estimated values of the proposed metric discriminated between the DBS ON and OFF states, and the verification of the DBS effect on the motor sign of each individual. The specific Gaussian models can be used as part of a closed-loop DBS system to estimate the tremor severity of patients.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
In this paper it is proposed an alternative method for detecting electromyographic (EMG) activity using inertial sensors, together with a comparison between the performance of the proposed method with two computer-based methods available... more
In this paper it is proposed an alternative method for detecting electromyographic (EMG) activity using inertial sensors, together with a comparison between the performance of the proposed method with two computer-based methods available in the literature. Visual inspection was adopted as the golden standard for detecting EMG signals. The comparison was made by calculating the difference of time between the detection of a trained observer and the time annotated by 3 different computer based-methods. The EMG signal was captured from 12 individuals while performing wrist extension from the extensor and flexor muscles of the wrist. The results showed that the proposed algorithm is superior to detect EMG activity when compared to the traditional ones. In conclusion, the use of inertial sensors together with electromyography reduces errors in the estimate of the beginning of the activity, when compared to the case in which the only available information is electromyography.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Gait disorders are important disabling symptoms in Parkinson's Disease (PD), which limit mobility, decrease quality of life and lead to loss of independence and autonomy. PD progression brigns episodic gait disorders, such as... more
Gait disorders are important disabling symptoms in Parkinson's Disease (PD), which limit mobility, decrease quality of life and lead to loss of independence and autonomy. PD progression brigns episodic gait disorders, such as festinated gait and freezing of gait, which do not affect all patients equally, but have a negative physical and emotional impact on the individual with these signs, in addition it may result in falls and associated injuries. The research group NIATS (Center of Innovation and Technology health) noticed the need to create a protocol for the qualitative and quantitative assessment of gait disorders in PD, in the ON and OFF states. Therefore, this work presents the development of a protocol for gait analysis using inertial sensors (quantitative assessment) of PD patients with and without the freezing symptoms, during ON and OFF states. This protocol includes skip the first dose of medication of the day; a quick cognitive test called Mini Mental; part II and II...
Research Interests:
This is the code for performing factor analysis in R. It can be used to validate some evaluation instrument, such as a questionnaire.
Research Interests:
Clinical diagnosis of Parkinson’s disease (PD) motor symptoms remains a problem. Most of the current studies focus on objective evaluations to make the evaluation more reliable. Most of these systems are based on the use of inertial and... more
Clinical diagnosis of Parkinson’s disease (PD) motor symptoms remains a problem. Most of the current studies focus on objective evaluations to make the evaluation more reliable. Most of these systems are based on the use of inertial and electromyographic sensors that require contact with the body part being assessed. Contact sensors restrict natural movement, may be uncomfortable and may require preparation of the body, which may cause irritation. As an alternative to contact sensors for the study of hand motor tasks performed by subjects with and without PD, electrical potential sensing technology is used in this research. A custom hardware has been designed to enable data collection by hand movement. A micro-machine system validated the developed system, and a relationship model was established between hand displacement and non-contact capacitive (NCC) sensor response. An experiment was conducted, including 57 subjects, 30 with PD (experimental group) and 27 healthy control group,...
Research Interests:
Muscular stiffness is one of the main symptoms of Parkinson’s disease. This symptom can manifest in different areas of the body, being more common in the upper limbs, which makes it difficult to perform activities involving the use of... more
Muscular stiffness is one of the main symptoms of Parkinson’s disease. This symptom can manifest in different areas of the body, being more common in the upper limbs, which makes it difficult to perform activities involving the use of hands. This study presents results obtained from the ergonomic evaluation of an active wrist orthosis for the rehabilitation of wrist flexion and extension movements of individuals with Parkinson’s disease who have symptoms of muscular rigidity. The study focused on assessing the muscular strength required to initiate wrist flexion and extension in healthy subjects. In order to evaluate this strength, electromyographic signals of each subject were acquired during Maximum Voluntary Contraction while the subjects executed wrist flexion and extension movements with and without the use of the orthosis. The mean of peaks of the maximum envelop of the EMG signals was used as an indicator of the muscular strength. The results suggest that the use of the devic...
Research Interests:
This work presents a model of the human neuromusculoskeletal system for investigation of the postural control in standing. In addition to the extrafusal muscle tissue properties, commonly used in traditional muscle models applied to the... more
This work presents a model of the human neuromusculoskeletal system for investigation of the postural control in standing. In addition to the extrafusal muscle tissue properties, commonly used in traditional muscle models applied to the study of human movement and posture, this model takes also into account the intrafusal muscle tissue properties and the intrinsic reflex responses provided by three neuromuscular organs (muscle spindles, Golgi tendon organs and Rhenshaw cells), which are two physiological components relevant in a postural control system. The proposed model treats the body as a single-link inverted pendulum operated by a pair of muscle-reflex actuators controlled by a proportional-integral-derivative (PID) controller. Simulations were made with and without the contribution of the modeled reflex responses. They showed fundamental properties of the somatosensory feedback system reported in investigations employing experimental data: (i) its anticipatory characteristic; ...
Research Interests:
Gait is a complex motor skill. However, most falls in humans occur during gait, and people with lower limb amputation have an increased risk of falls. Thus, this study evaluated the stability of persons with unilateral amputation by... more
Gait is a complex motor skill. However, most falls in humans occur during gait, and people with lower limb amputation have an increased risk of falls. Thus, this study evaluated the stability of persons with unilateral amputation by quantifying the margin of stability (MoS) during gait, to contribute to understanding the strategies adopted by these people to reduce falls. The participants were divided into 3 groups: persons with transtibial amputations (n = 12, 32.27 ± 10.10 years, 76.9 ± 10.3 kg, 1.74 ± 0.06 m); persons with transfemoral amputations (n = 13, 32.21 ± 8.34 years, 72.55 ± 10.23 kg, 1.73 ± 0.05 m); and controls (n = 15, 32.2 ± 10.17 years, 75.4 ± 9.25 kg, 1.75 ± 0.05 m), who walked for 4 min on a level and sloped (8% down and up) treadmill. The pelvic and foot marker kinematic data were used to estimate the center of mass and base of support, and from these, the MoS was estimated. Although both groups of persons with amputations showed higher values for the ML MoS than did the control group (transtibial: 8.81 ± 1.79, 8.97 ± 1.74, 8.79 ± 1.76, transfemoral: 10.15 ± 2.03, 10.60 ± 1.98, 10.11 ± 1.75, control: 8.13 ± 1.30, 7.18 ± 1.85, 8.15 ± 1.57, level, down, and up, respectively), only the transfemoral group presented a significant higher value compared to the control group. Our findings suggest that the documented limitations in persons with amputations, especially with transfemoral amputation, are exacerbated in situations that require more skills, such as walking on sloped surfaces, triggering protective mechanisms.
Research Interests:
Research Interests:
Over the years, a number of distinct treatments have been adopted for the management of the motor symptoms of Parkinson's disease (PD), including pharmacologic therapies and deep brain stimulation (DBS). Efficacy is most often... more
Over the years, a number of distinct treatments have been adopted for the management of the motor symptoms of Parkinson's disease (PD), including pharmacologic therapies and deep brain stimulation (DBS). Efficacy is most often evaluated by subjective assessments, which are prone to error and dependent on the experience of the examiner. Our goal was to identify an objective means of assessing response to therapy. In this study, we employed objective analyses in order to visualize and identify differences between three groups: healthy control (N = 10), subjects with PD treated with DBS (N = 12), and subjects with PD treated with levodopa (N = 16). Subjects were assessed during execution of three dynamic tasks (finger taps, finger to nose, supination and pronation) and a static task (extended arm with no active movement). Measurements were acquired with two pairs of inertial and electromyographic sensors. Feature extraction was applied to estimate the relevant information from the ...