Sharif Digital Repository

Tinnitus is variety of sounds heard when no corresponding external sound is present. To remedy this condition, various methods have been proposed, however none have resulted in systematic and lasting results. This study aims to investigate the efficacy of non-invasive electrical stimulation techniques (tES) in the treatment of tinnitus. Stimulation parameters, including intensity, frequency, duration, and session frequency, are tailored to the individual's subjective tinnitus characteristics and treatment goals. Specifically, transcranial direct current stimulation (tDCS) is explored as a non-invasive method of electrical stimulation. In the tDCS method, electrodes are strategically... 

Medical ultrasound imaging is one of the common imaging methods in modern medicine, which is used to diagnose and even treat some diseases due to its cheapness and harmlessness. Medical ultrasound transducer arrays have a significant error rate. They are a major cause of failure in ultrasound imaging systems. This problem causes a noticeable decrease in the quality of the images and medical misdiagnoses. The topics of accurate detection of the location and severity of the error or failure, as well as the compensation for weak transducers by signal processing methods, have received less attention from predecessor researchers. In this thesis, an innovative method for accurate error detection... 

Tinnitus means hearing a sound without an external source. Despite the research done in relation to it, it is still an unknown phenomenon and no method has been introduced to treat it. Repetitive transcranial magnetic stimulation is one of the methods that its effectiveness in decreasing tinnitus sound is still under investigation. This technology is a non-invasive method to stimulate the brain, which modulates the activity of neurons by applying successive electromagnetic pulses on the scalp. Most of the studies conducted in this field have used clinical evaluations to investigate the effect of stimulation. Relying on this method alone to evaluate the effect of stimulation cannot take a... 

Wireless area body networks (WBANs) are a set of sensors designed to monitor an individual’s health remotely. These networks are required to transfer the data properly to the healthcare professional. Since there is no guarantee that no faults might occur, these networks should have fault tolerance capability such that they can maintain their main function properly. In this thesis, a method for fault tolerance in WBANs is proposed.In this research, to test the proposed method, a case study on sleep apnea disorder is selected for monitoring patients who experience sleep apnea. To this end, the Apnea-ECG dataset from the PhysioNet repository was considered which contains five different types of... 

Humans, as a diploid species, have two nucleotide sequences of homologous chromosomes in their genomes, where one set is inherited from the mother, and the other comes from the father. The Single Individual Haplotype assembly problem (SIH) refers to the reconstruction of these two distinct nucleotide sequences of a chromosome from the sequencing reads, and it is currently considered one of the most important issues in the field of computational genomics, which plays an essential role in solving various genetic and medical problems.Nowadays direct experimental methods are not welcomed due to their high cost, and labor intensity, and are limited to certain regions of the genome, therefore,... 

Subcutaneous needle insertion is one of the key methods of limited invasive surgery in medical diagnosis and treatment. However, errors in needle targeting can reduce the effectiveness of such efforts. One of the main factors of errors is due to the human guidance of the needle, which many researches have approached in recent years, and among the suggested solutions is the use of automatic or semi-automatic assist systems. Considering the treatment of prostate cancer by brachytherapy method, this research has developed a semi-automatic physician assistance system using navigation based on the potential field method and ultrasound images of the needle location, and sliding mode fuzzy... 

Identifying and interpreting standard fetal plates in first trimester examinations with two-dimensional ultrasound is a very complex task that requires years of experience. Aside from the challenge to position and direct the probe to required positions, there is an understandable difficultly for inexperienced sonologists to identify the corresponding structures in the emerging images. Automated image processing can be helpful both to the experienced as well as inexperienced operators to confront these challenges. In this study, we used data from three different devices SAMSUNG WS80A, VOLUSON E6, VOLUSON E8, which includes a total of 2230 images to measure the thickness of the space behind... 

Ultrasound imaging is one of the most widely used diagnostic methods in medicine due to its safety, cost-effectiveness and small and portable size of equipment. In this imaging method, line-by-line scanning is used to create the image, which has limitations in speed and resolution. To deal with these limitations, new methods have been proposed, such as plane-wave imaging with the possibility of increasing the imaging speed and synthetic apertures with the possibility of increasing the quality of images. By combining these two methods, high quality and speed can be achieved simultaneously. Therefore, in this research, based on previous studies, a number of elements were activated each time,... 

According to clinical surveys, it is estimated that chronic tinnitus is experienced by 10 to 15% of the adult population. Tinnitus is defined as the conscious and involuntary perception of noise or ringing without involvement of either mechanical or external audio source. In recent years, a limited number of studies have investigated the effects of applying transcranial magnetic stimulation (TMS) to ameliorate this condition. TMS is a noninvasive intervention in which magnetic pulses are applied by a coil adjacent to the individual's head. In this study, electroencephalogram (EEG) signals are recorded concurrent and as a follow-up to TMS. This makes it possible to study changes caused by... 

Tinnitus is commonly referred to the symptom of “ringing in the ear”, and it is scientifically described as the perception of sound in the absence of an acoustic event. This symptom is powerful enough to negatively affect sleep patterns and concentration. The symptoms affect more than forty-five million people only in the US and 10 to 20% of the world population. Management and treatment of subjective tinnitus is an ongoing focus of research activities. Ample evidence suggests that the mechanism of tinnitus involves maladaptive plasticity in both classic and non-classic auditory pathway. The non-classical pathway is referred to multi-modal sensory inputs to the auditory system, limbic... 

LFP characteristics have been shown to be informative of sensory stimuli and influenced by attention. We show the gamma power in area MT is selective to motion direction showing a Gaussian tuning curve. Here we show for the first time, some evidence based on a single monkey’s data that spatial attention enhances the tuning curve based on gamma power.The synchronization of activity across neurons has been a focus in many recent studies of information processing in networks of cortical cells and areas. One aspect of such inter-neuronal synchrony is the locking of spiking activity to local field potentials (LFPs). Such an interaction has been observed between the timing of individual action... 

With advancements in control and robotics technology, wearable robots have gained multiple applications in rehabilitation and power augmentation. In robots developed for power augmentation purposes, human decisions are combined with robot power to enhance the human ability to perform various activities, such as carrying heavy loads and walking for a long time. In cases where robots are designed to help humans to carry heavy loads, the robot control strategy should minimize the human-robot interaction forces. In this case, heavy loads influence the robot and the user no longer need to use more energy than normal walking, and the robot works following human intentions. Where the robot works to... 

Extensive studies have been performed on the genetic variations involved in common neurodegenerative diseases such as Alzheimer's, macular degeneration, and Parkinson's. In most cases, no specific gene has been identified pointing to a distinct pathogenic pathway, therefore, this study mainly aims to find common genes among aforementioned diseases according to determination of a specific pathogenic protein pathway.In this study, we reached a deep understanding of the function of nervous system and the discovery of causative agents of the diseases by applying the sources of information from genome datasets in bioinformatics analysis. The utilized database comprises the classification of... 

The quantity and quality of information extracted from the brain, in addition to data collection methods, is also related to the statistical tools used. As extracting maximum information in both temporal and spatial dimension require electrophysiological approaches on the physical side, the statistical methods should be optimized to that end, on the theoretical side. The time histogram method is the most basic tool for capturing a time-dependent rate of neuronal spikes. Generally, in the neurophysiological literature, the bin size that critically determines the goodness of the fit of the time histogram to the underlying spike rate has been subjectively selected by individual researchers.... 

In the literature of motor behavior, rapid and harmonious human movements and adaptation to limb dynamics are described with reference to internal models. Concepts of internal models in neuroscience cognitive sciences and computational modeling have been investigated and their structure and performance have been evaluated by behavioral, neurophysiological and medical imaging data. The purpose of the theory of internal models is to explain the mechanism of human movement. Based on this theory, the central nervous system uses internal models to predict and adjust movements and reduce uncertainty. Uncertainty refers to the unknown dynamics of the system due to the lack of access to accurate... 

Conventional MRI has been used to diagnose different types of brain injuries. However these methods have generally failed to diagnose mild types of injury. We are working on the specification of mild traumatic brain injury, using diffusion MRI data, based on a multi compartment simulation of white matter tissue. This effort is essential for better understanding of underlying tissue micro-structure changes in patients with trauma. Some studies have been used in similar data fitting approaches in order to estimate axon diameter distribution. Specifically, a comparative study between different Compartment Models has shown that “ActiveAx” model has the best agreement with underlying tissue... 

Neural modeling is a branch of cognitive science in which the behavior of the nervous system is described through a collection of mathematical relations. By using these models, it is possible to study certain features of the networks or predict brain responses to different stimuli. One of the important features in neural networks is the adaptation phenomena that occurs in different forms. All types of adaptation occur in presence of a constant stimuli through a set period of time. Adaptation causes a departure from the stable pattern of neural activities which makes the responses unpredictable. Hence, it is important to study the effects of adaptation on the network activities.This study... 

Tinnitus is known as a disorder in which a person is heard a sound without an external source. The tinnitus with brain disorder source is still unknown and in recent years, various experiments have proposed many hypotheses and tried to evaluate the structural differences of the brain in tinnitus with normal people. The combination of Transcranial Magnetic Stimulation (TMS) with ElectroEncephaloGram (EEG) provides a good evaluation system with good time resolution and fair spatial resolution. In this study, at first, based on a wide range of studies in the field of TMS on Tinnitus have been examined from the participants conditions and stimulation parameters aspects to suitable stimulation... 

Physiotherapy is a major part of the rehabilitation process that is used to retrieve patients' physical ability. The recuperation feedback in the physiotherapy process has a twofold significance for both physiotherapists and patients. It helps patients regain their ability to recover more quickly, prevent recurrence of injury to the treated area and other areas, and motivate the patient to continue treatment. It also helps the physiotherapist to monitor the process of rehabilitation and ensure the correctness of the procedure. Meanwhile, many patients cannot maintain continuous workouts due to lack of access to the physiotherapist at home and inability to provide required feedback.In this... 

Wireless Body Area Network (WBAN) is one of the emerging technological trends that paves the way for the next generation medical systems by offering proactive wellness management and early detection of diseases. WBAN, as standardized by IEEE 802.15.6, is a network composed of intelligent, miniaturized, low power sensors that are strategically implanted in, placed on, or in close proximity to the human body. The sensors have responsibility for recording vital physiological signals and wirelessly transmitting them to a central hub for further processing. In this study, we have first investigated the applicable channel models for a typical WBAN. Considering various scenarios with different...