Towards a Biomarker of Motor Adaptation: Integration of Kinematic and Neural Factors

We propose an experimental protocol for the integrated study of motor adaptation during target-based movements. We investigated how motor adaptation affects both cerebral activity and motor performance during the preparation and execution of a pointing task, under different conditions of external perturbation. Electroencephalography (EEG) and movement analysis were simultaneously recorded from 16 healthy subjects enrolled in the study. EEG signal was preprocessed bymeans of independent component analysis and empirical mode decomposition based Hilbert Huang transform, in order to extract event-related synchronization (ERS) and desynchronization (ERD) parameters. Movement analysis provided several kinematic indexes, such as movement durations, average jerk, and inter-quartile-ranges. Significant correlations between score, neural, and kinematic parameters were found. Specifically, the duration of the going phase of movement was found to correlate with synchronization in the beta brain rhythm, in both the planning and executive phases of movement. Inter-quartile ranges and average jerk showed correlations with executive brain parameters and ERS/ERDcueBeta, respectively. Results indicate the presence of links between the primary motor cortex and the farthest ending point of the upper limb. In the present study, we assessed significant relationship between neural and kinematic descriptors of motor adaptation, during a protocol requiring short-term learning, through the modulation of the external perturbations

The Development of an Antagonistic SMA Actuation Technology for the Active Cancellation of Human Tremor.

Human Tremor is an unintentional bodily motion that affects muscle control among both healthy individuals and those with movement disorders, occasionally to severe detriment. While assistive devices avoid the risk of side effects from pharmacological or surgical treatments, most devices are impractical for daily use due to limitations inherent in conventional actuators. The goal of this research is to address these limitations by developing an antagonistic Shape Memory Alloy (SMA) actuation technology, enabling a new class of active tremor cancellation devices. This is accomplished through the construction of a model and body of empirical support that provides the necessary design insight and predictive power for an antagonistic actuator that ensures stable amplitude and high frequency motion with low power draw. Actuation frequency and power draw were improved while balancing their competing effects through the development of: 1) a method that accurately measures the convective coefficient of SMA to enhance actuator design, 2) a growth process for carbon nanotube cooling fins to enhance cooling in a fixed medium, and 3) an understanding of the antagonistic architecture to produce increased frequency in a controllable manner. To enable applications requiring predictability for positioning and complex control, a thermodynamic model for antagonistic SMA was derived to account for inertial, slack, boiling, friction, and convective effects. Using the model, a series of simulation studies provided design insight on the effect of operating environment, driving signal, and environmental conditions so that the generic actuation system can be utilized in a wide variety of applications beyond tremor cancellation. If high forces are required in such applications, stability issues can arise, which were addressed in experimental shakedown research that broadens the high-stress SMA design space. The technology enabled by this dissertation was demonstrated in a working Active Cancellation of Tremor (ACT) prototype that produced 71% RMS cancellation of human tremor. The cancellation results show significant improvement over the current state of the art by providing intuitive, lightweight, compact hand-held tremor cancellation that is a promising solution to numerous assistive applications in medical, military, and manufacturing sectors.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/76010/1/apathak_1.pd

Evaluating a sensor of skin conductance to assess dental anxiety

Tese de mestrado, Bioinformática e Biologia Computacional (Bioinformática), Universidade de Lisboa, Faculdade de Ciências, 2015The anxiety related problems that adult population experience, are a common issue in Dental Practice. To overcome these problems it would be helpful to have an objective measure of the current anxiety of the patient. With this information, it should be possible to link the measured anxiety to an automated system that could distract the patient by altering the surrounding environment, i.e. Ambient Intelligence. This project consisted in measuring the skin conductance signal and correlating the responses related with documented dental stressful procedures. This was executed in a real clinical environment. Dental anxiety was assessed in over 70 patients with a 3 question survey using the Likert scale. Each answer was registered together with the level of skin conductance measured with a sensor placed in the patient fingers. The results showed a significant association between the dental anxiety score on two of the questions and the quantified skin electrodermal response. These findings aim to help design a future system based on ambient intelligence to distract and reduce dental anxiety during treatment.Uma parte significativa da população adulta tem problemas provocados pela ansiedade originada com a ida à consulta de Medicina Dentária. Seria vantajoso existir uma avaliação objetiva do nível de ansiedade do paciente durante a consulta para se ultrapassar estes problemas. Com esta informação seria possível alterar o ambiente envolvente através da ligação a um sistema automatizado inteligente para a distração do paciente durante a consulta. Este projeto consistiu na medição do sinal de condutividade da pele e correlação desta com as respostas a um questionário relacionado com atos dentários reconhecidos como causadores de grande ansiedade dentária. A ansiedade dentária foi avaliada em cerca de setenta pacientes por um questionário de três perguntas utilizando uma escala de Likert. Simultaneamente foi medida a condutividade da pele por um sensor colocado nos dedos da mão. Os resultados mostram uma associação significativa entre o nível de ansiedade obtido em duas das questões e a alteração da condutividade da pele. Estes resultados visam fornecer uma base para desenhar um futuro sistema de Ambiente Inteligente para distração da ansiedade dentária

Deep brain stimulation for disorders of consciousness and diminished motivation:A search for awakenings

This thesis deals with patients who are amongst the most severely affected after severe brain injury: those with permanent disorders of consciousness or diminished motivation. The research in this thesis is an attempt to improve consciousness and the general behavioral performance of these patients with the use of experimental interventions, including medication (such as zolpidem), and more invasive procedures, such as deep brain stimulation (DBS). The thesis contains extensive descriptions of the role of the intralaminar thalamus in the arousal regulation system, the importance of recognizing and treating secondary complications after brain injury, such as hydrocephalus, as well as a pathophysiological elaboration on akinetic mutism: a severe disorder of diminished motivation. Moreover, it describes the neurophysiological changes that accompany the paradoxical effects of zolpidem, a sleeping pill that temporarily induces ‘awakenings’ in some patients with severe brain injury. Further, it describes the first clinical and neurophysiological results of an N=6 trial of DBS in patients with a minimally conscious state and shows the importance of recognizing pathological changes from the brain’s ‘physiological baseline’ that seem to disturb normal brain functions. The thesis concludes with a description of the use of moral case deliberation in dealing with research dilemmas in patients with loss of autonomy after severe brain injury

N.M.R. Investigation of Dynamic Molecules Containing Elements of Groups V or VI

a) Chalcogen inversion in (Et2X)2MHal2 complexes. The objective of this work was to establish pyramidal chalcogen (S,Se and Te) inversion and to ascertain which factors might influence the inversion rate in a series of transition metal complexes. Monodentate chalcogen complexes of the type (Et2X)2MHal2 (X = S,Se or Te; M = Pt or Pd) were examined by variable temperature NMR spectroscopy the issues arising from this choice forming the basis of further research. Both sulphur and selenium invert when coordinated to platinum, this being the first ever report of pyramidal selenium inversion. The rate of sulphur inversion depends on the nature of the ligand trans to the inverting centre. The geometries of the complexes in solution were established by dipole-moment measurements, which revealed in almost every case a trans-configuration. Contrary to popular belief, the (Et2Te)2MHal2 complexes are trans in solution. A cis arrangement of inverting centres was effected by the synthesis of (EtSeC2H4SeEt)MHal2 complexes and the VTNMR results showed that the rate of selenium inversion also depends on the nature of the trans-ligand. The retention of 195pt-x-C-H coupling (195Pt, I = 1/2, 33.7% abundant) after coalescence served to differentiate between a pyramidal inversion and a ligand exchange mechanism in the platinum monodentate complexes, but the absence of a suitable magnetic isotope of palladium of sufficient abundance meant that pyramidal chalcogen inversion in palladium complexes alone could not be unequivocally established. Addition of excess ligand to these complexes showed that ligand exchange was not involved at these temperatures and unambiguous sulphur inversion in the (Et2S)2PdHal2 complexes was demonstrated. The order of ease of ligand exchange was shown to be Et2Te " Et2Se > Et2S. The pronounced effect of traces of diethyltelluride on the spectra of the (Et2Te)2PtHal2 complexes offered a rationalisation of the high temperature spectra of these complexes when no excess ligand had been added. 195Pt-Te-C-H coupling was never observed at temperatures above those of coalescence, almost certainly due to a ligand exchange-recombination mechanism as a result of the decomposition of these complexes at high temperatures. The question of whether or not tellurium inverts led to many attempts to produce a suitable tellurium-containing complex, culminating in the synthesis of cis-(Et2Te)2Pt(p-tolyl)2 which showed VTNMR characteristics consistent with pyramidal tellurium inversion. This represents the first unambiguous proof of such a mechanism. The order of ease of inversion within the chalcogens is S > Se > Te, and palladium complexes have faster inversion rates than analogous platinum complexes. Lastly, a series of benzyl complexes, trans-(Bz2S)2PdHal2 was examined by VTNMR with the intention of calculating Free Energies of Activation for the inversion process by computer methods. These were not obtained, since at low temperatures other signals and coalescences were observed. Rationalisations in terms of cis-isomers are presented. b) Hindered rotation about P-N bonds. A series of compounds of the type Ph2P-N(R)-P(Ph)Cl (I) was prepared, (R = Me, Et, Prn, Pri or Bu t). 31P and 1H{31P} NMR spectra were obtained and from the coalescence temperatures it was established that the torsional barriers are dependent on the steric requirement of the R group on nitrogen -the order of ease of rotation being R = Me>Et"Prn > Pr i> Bu t. The variation in P-N-P coupling constant with temperature is related to the two dihedral angles between the lone pairs on both phosphorus atoms and the P-N bonds of the other phosphorus atoms. This enabled low temperature conformational preferences to be assigned. For (I), (R = Me, Et, Prn), this is the (0,0) conformer (ie. two

Abstracts of Papers, 84th Annual Meeting of the Virginia Academy of Science

Full abstracts of papers for the 84th Annual Meeting of the Virginia Academy of Science, May 25-26, 2006, Virginia Polytechnic Institute and State University, Blacksburg, V

Case Record

UNDIFFERENTIATED SCHIZOPHRENIA: Mr. R was reported to be normal 4 years back, he was found to be preoccupied and not communicating well with his family members and preferred to stay alone. He was talking and laughing to self. When asked he said that he heard voices speaking to him and he were replying to it. Gradually his sleep decreased and he would sleep only for 3 to 4 hours at night. He did not attend classes. He was started washing his room many times. He was taking bath frequently. He was started worshiping god Anjanaya many times a day and also avoiding to speak with female family members. This continued for 2 months after which he started to be abusive and assaultive others for no reason. So he was taken to a psychiatrist, was admitted for 10 days and treated with ECT. After discharge he would discontinue medications on and off during which his symptoms would get exacerbated. He continued his studies but performance was poor. He also exhibited suicidal gestures on three occasions in the form of cutting his harms and carrying kerosene and matchbox inside the bathroom, saved by family members. Again the mother took him to psychiatrist and continued medication the symptoms were under the control. He completed his course but did not complete his studies. Then he got employment into Ford Company, his performance was average, he continued his job for 5 months with medication. After discontinue of treatment he became self-withdrawn, slowly he was neglecting self-care, attempted suicide, coworkers informed to his parents. Hence he was brought to IMH and admitted. No H/O sad mood, crying spells. No H/O tall claims, spending spree. No H/O thoughts being known to others or withdrawn. No H/O substance use. No H/O head injury, LOC, seizures. No H/O fever or any prolonged drug intake. SUBSTANCE INDUCED MOOD DISORDER: The patient was introduced to using betelnut along with his friends around 18 years of age. Later be continued to use tobacco in the form of Panparag, Hans, Shanthi betelnut 4-6 packets per day. Later after 3 years of tobacco intake, he started consuming alcohol for the first time along with his friends on some occasion, he consumed beer around 200ml. As he enjoyed the high produced by the drink, he continued to take alcohol at regular interval. After 1 year of beginning alcohol intake, he got married, after 6months of marriage life he started consuming alcohol in the form of brandy almost every night. He would become intoxicated, come home, abuse and assault his wife frequently. Due to frequent marrital dishormony his wife left and living with her grand parants for past 8 months. Now according to his be continued to drink alcohol, but the past two months he was engaged in some temple work, where he is supposedto have been introduced to cannabis.After consuming cannabis, his behavior became unmanageble. He frequently keep standing in the middle of the road and appear to make gesturesas if regulating the traffic. He would keep talking excessively and laugh for unprovoked reasons. His sleep patterns also worsened. All through out the night he would keep wandering in the street. And also he was started talking irrelevantly and would not be able to brought back home. He would also talk high about himself. He would claim himself to be God and capable of doing lot of things and able to grant wishes to all people. His selfcare also deteriorated, he started picking up quarrles and assaulted others. Nighbours made complaint against him. So, the family members brought him in the confused state to IMH. He was treated with Ing. Lorazepam 4 mg IM stat and referred to GGH for favour ofadmission and rule out other causes of delirium. He was treated at GGH for one week with Inj. Haloperidal 5 mg, Inj. Lorazepam 4 mg im, Inj.Thiamine and has been referred to IMH for further management. No h/o head injury/LOC/seizures. No h/o low mood/crying spells/suicidal attempts. No h/o hearing voices No h/o repititive washing/cheeking etc., DELUSIONAL DISORDER-MIXED: The patient was reported to be normal till one year eight months back. She claimed hat her co-tenant Mr. V called her for sexual relationship and she refused after that she started telling that he is setting people against her to harm her and also setup prostitutes as a co-tenants, to move her away from the place She also says that he tried to kill her with ambulance 108 and milk van by using his political influence. Patient gave complaint in nearby police station about Mr. Enquiry done. But the police Also turned against her by his political influence. So, she used to go to SP office, collector office daily and shout to arrest Mr. V. Mean while she vacated that house and shifted to Mr. S house who is friend of her brother. He is a widower, living alone. After 2 months of shifting to new house she started believing that the house owner was deeply loved with her whom she understands by his Gestures. And he did not admit his love for her has he did not want others to know. She was fought with the co-tenant once for silly reason. They were assaulted her with an aluminum mug and broken house hold article. And she assumed that Mr. V. only arranged them to fight with her. And also without any reason the patient was fought with the female Co-tenants whoever talking to Mr. S. She uses to tell everybody that the Mr. S. loves with her. The house owner warned them to vacate the house. But she did not vacate the house. The house owner slowly cut power supply, water supply to her portion. After 4 months she vacated the house to Next Street. Even after vacating, patient goes to Mr. S. house and starts quarrel with the new tenants that they should vacate and only because of them he is avoiding her. Every day she was going to her old house and tells everybody that the house owner loves with her. The husband told her not to go there, but she poured kerosene on him and try to kill him. So, the house owner filed a case against her, she was arrested and kept in observation at IMH. During observation she was continuously blaming the old co-tenant that all because him only it happen. Still the house owner his loves with her, she also loves him deeply. DEMENTIA IN ALZHEIMER’S DISEASE: The patient was reported to be normal till one year back. Then, her daughter noticed that the patient repeatedly searched for certain things in the house. She would forget simple things in the house like the way for going to toilet. At times she also found it difficult to return to her house after going for a walk. In course of time, she was not able to identify her close relatives. She was not able to remember whether she had taken her food or not. Her personal hygiene decreased gradually. She did not take bath and did not dress properly. She would pass urine inside the house itself at times. She slept for very little time and would wake up in the middle of the night and keep pacing inside the house.Slowly she was not able to identify her own family members. MENTAL RETARDATION-MILD: Patient was born out of non consanguineous marriage, full term normal delivery. Mother was 22 yrs and fathers age was 298 yrs. No history of any drug intake, fever or exanthematous eruptions in the ante natal period. No ante natal checkup was done. No history of radiation, injury, malnutrition, or vaginal bleeding. Delivery was conducted by local dhai; h/o prolonged 2nd stage of labor, the baby cried soon after birth and was breast fed after a short while. No h/o neonatal seizures or difficulty in feeding. No h/o of jaundice, breast fed up to 10 months, and there were no weaning difficulties

Oscillatory activity in the basal ganglia - is it relevant to movement disorders therapy?

Chronic high frequency stimulation of the basal ganglia can be a highly effective intervention for movement disorders in patients. In the past decade, therapeutic benefits have been seen with stimulation of the subthalamic nucleus and globus pallidus interna for Parkinson's disease (PD) and dystonia, respectively. These procedures have allowed direct recording of basal ganglia activity and have suggested that abnormal synchronisation of neurons in these nuclei may contribute to motor impairment. This thesis explores the possible correlation between synchronised activity in the basal ganglia, as evidenced by oscillations in local field potentials, and movement disorders. In Chapter 3, we demonstrate the correlation between synchronization at frequencies under 10 Hz in the globus pallidus interna and dystonic EMG. This low frequency activity is shown to be locked to neuronal activity within GPi in patients with dystonia (Chapter 4). Deep brain stimulation is thought to suppress spontaneous pathological activity in the basal ganglia. Equally, however, it must also suppress any residual physiological activity in these nuclei. In Chapter 5, we demonstrate that the basal ganglia are involved in the processing of simple limb movements in the human, by separating the effects of deep brain stimulation on pathological and physiological activities based on baseline task performance. An impairment of motor performance was seen during high frequency stimulation in those patients with the best task performance at baseline. This deleterious effect, however, should be distinguished from the effect of direct stimulation at 20 Hz in Parkinson's disease. Oscillatory activity at around 20 Hz is thought to be a core feature in Parkinson's disease. In Chapter 6, we demonstrate that the excessive synchronization imposed by stimulation of the subthalamic nucleus at 20 Hz slows movement, in those patients with the best task performance at baseline. This supports the notion that synchronization around 20 Hz may be causally linked to bradykinesia. Last, the therapeutic effectiveness of DBS therapy for patients with PD partially relies on the accurate localisation of the motor region of the subthalamic nucleus. In Chapter 7, we propose an alternative method for the localization of this region using the spontaneous pathological 20 Hz activity to be found in this nucleus. The findings of these studies provide evidence that basal ganglia oscillatory activities of differing frequencies contribute to movement disorders