Acquisition of ownership illusion with self-disownership in neurological patients

The multisensory regions in frontoparietal cortices play a crucial role in the sense of body and self. Disrupting this sense may lead to a feeling of disembodiment, or more generally, a sense of disownership. Experimentally, this altered consciousness disappears during illusory own-body perceptions, increasing the intensity of perceived ownership for an external virtual limb. In many clinical conditions, particularly in individuals with a discontinuous or absent sense of bodily awareness, the brain may effortlessly create a convincing feeling of body ownership over a surrogate body or body part. The immediate visual input dominates the current bodily state and induces rapid plastic adaptation that reconfigures the dynamics of bodily representation, allowing the brain to acquire an alternative sense of body and self. Investigating strategies to deconstruct the lack of a normal sense of bodily ownership, especially after a neurological injury, may aid the selection of appropriate clinical treatment

The homuncular jigsaw: investigations of phantom limb and body awareness following brachial plexus block or avulsion

Many neuropsychological theories agree that the brain maintains a relatively persistent representation of one's own body, as indicated by vivid "phantom" experiences. It remains unclear how the loss of sensory and motor information contributes to the presence of this representation. Here, we focus on new empirical and theoretical evidence of phantom sensations following damage to or an anesthetic block of the brachial plexus. We suggest a crucial role of this structure in understanding the interaction between peripheral and central mechanisms in health and in pathology. Studies of brachial plexus function have shed new light on how neuroplasticity enables "somatotopic interferences", including pain and body awareness. Understanding the relations among clinical disorders, their neural substrate, and behavioral outcomes may enhance methods of sensory rehabilitation for phantom limbs

Development and Validation of a Wearable Device to Provide Rich Somatosensory Stimulation for Rehabilitation After Sensorimotor Impairment

: Training sensory discrimination of the skin has the potential to reduce chronic pain due to sensorimotor impairments and increase sensorimotor function. Currently, there is no such device that can systematically provide rich skin stimulation suitable for a training protocol for individuals with amputation or major sensory impairment. This study describes the development and validation of a non-invasive wearable device meant to repeatedly and safely deliver somatosensory stimulations. The development was guided by a structured design control process to ensure the verifiability and validity of the design outcomes. Two sub-systems were designed: 1) a tactile display for touch and vibration sensations, and 2) a set of bands for sliding, pressure, and strain sensations. The device was designed with a versatile structure that allows for its application on different body parts. We designed a device-paired interactive computer program to enable structured sensory training sessions. Validation was performed with 11 individuals with intact limbs whose upper arm tactile sensitivity was measured over 5 training sessions. Tactile discrimination and perception threshold were measured using the standard 2-point discrimination and Semmes-Weinstein monofilament tests, respectively. The results of the monofilament test showed a significant improvement (p = 0.011), but the improvement was not significant for the 2-point discrimination test(p = 0.141). These promising results confirm the potential of the proposed training to increase the sensory acuity in the upper arms of individuals with intact limbs. Further studies will be conducted to determine how to transfer the findings of this work to improve the pain and/or functional rehabilitation in individuals with sensorimotor impairments

Design and Development of a Multimodal Vest for Virtual Immersion and Guidance

This paper is focused on the development of a haptic vest to enhance immersion and realism in virtual environments, through vibrotactile feedback. The first steps to achieve touch-based communication are presented in order to set an actuation method based on vibration motors. Resulting vibrotactile patterns helping users to move inside virtual reality (VR). The research investigates human torso resolution and perception of vibration patterns, evaluating different kind of actuators at different locations on the vest. Finally, determining an appropriate distribution of vibration patterns allowed the generation of sensations that, for instance, help to guide in a mixed or virtual reality environment

Sound Perception:Encapsulating Intangible Voice Memories in a Physical Memento

We live in a very busy world with a variety of sensory stimulation including the olfactory, visual, tactile, and auditory. The five senses are triggered by our surroundings and help us to form meaning about the world.ⅰ Based on where someone grows up, she or he is introduced to various sites and sounds, affecting how they interpret the world. Sounds relate meaning through the association between hearing, memory and an event. Hearing is one of the learning processes, in which individuals give, receive, and store information. We typically rely on our five senses, which contribute to the process of understanding, communicating, and comprehending information. Moving beyond visual perception requires systematic attention to individual learning modalities.ⅱ Sound is one of the developing areas in the field of perception that moves beyond vision to help people understand nature, objects, narratives and varieties of perception. In order to comprehend how people hear, it is important to understand the role of perception. Sound functions as a signal, but also varies according to the capacity to hear. An individual’s physical ability to hear, and their unique experiences with sound, differ from one person to the next, and can result in a range of emotions and reactions. Certain sounds, like the voice of a loved one, also have the power to trigger emotion and convey meaning due to the association between hearing, memory and specific events from one›s past In short, the three aspects of sound perception–signal, hearing, and emotional reaction–play an integral role in auditory perception and the subjectivity of sound. However, the value of sound is often taken for granted or viewed as secondary to visual perception. This thesis will explore the value of sound perception by investigating two of its primary aspects–hearing and emotional response–in application to memory. Through a series of experiential objects, that trigger the senses. The aim is to utilize design to memorialize precious sounds in order to raise awareness about the emotional value of sound to the human experience

Mental maps and the use of sensory information by blind and partially sighted people

This article aims to fill an important gap in the literature by reporting on blind and partially sighted people's use of spatial representations (mental maps) from their perspective and when travelling on real routes. The results presented here were obtained from semi-structured interviews with 100 blind and partially sighted people in five different countries. They are intended to answer three questions about the representation of space by blind and partially sighted people, how these representations are used to support travel, and the implications for the design of travel aids and orientation and mobility training. They show that blind and partially sighted people do have spatial representations and that a number of them explicitly use the term mental map. This article discusses the variety of approaches to spatial representations, including the sensory modalities used, the use of global or local representations, and the applications to support travel. The conclusions summarize the answers to the three questions and include a two-level preliminary classification of the spatial representations of blind and partially sighted people

Assessment of Sensory Abnormalities in Children with ASD Using Virtual Reality

Sensory abnormality is one of the important characteristics of Autism Spectrum Disorder(ASD). A large number of studies suggest a strong connection between sensory abnormalities and ASD. Therefore, it is important to assess sensory abnormalities for diagnosis and intervention of ASD. In this thesis study, we aim to develop a virtual reality system that can measure sensory abnormalities in adolescents with ASD. Sensory abnormalities can affect all five senses: touch, vision, smell, taste and auditory. However, in this study, we focus on assessing sensory abnormality in vision and touch sensory processing. Twelve adolescents with ASD and 12 typically developing (TD) adolescents aged 11-17 years participated in the study. Participants were assigned a task in which they interacted with the virtual reality system. The system recorded participants’ behavior and their response to the virtual environment in the real time while they completed the task. We defined four measurements to analyze the behavior of the participants. With the help of the defined measurements, we found some significant differences in the way participants with ASD and TD participants interacted with the virtual environment. Participants also filled a commonly used standard psychological assessment questionnaire called Adult/Adolescent Sensory Profile (AASP). Strong correlations between some of the scores in the questionnaire and their response to the virtual environment were also observed. Therefore, this pilot study supports the use of technology to assess sensory abnormalities and shows that further research into the development of such technology is essential

Heterosexual, gay, and lesbian people’s reactivity to virtual caresses on their embodied avatars’ taboo zones

Embodying an artificial agent through immersive virtual reality (IVR) may lead to feeling vicariously somatosensory stimuli on one’s body which are in fact never delivered. To explore whether vicarious touch in IVR reflects the basic individual and social features of real-life interpersonal interactions we tested heterosexual men/women and gay men/lesbian women reacting subjectively and physiologically to the observation of a gender-matched virtual body being touched on intimate taboo zones (like genitalia) by male and female avatars. All participants rated as most erogenous caresses on their embodied avatar taboo zones. Crucially, heterosexual men/women and gay men/lesbian women rated as most erogenous taboo touches delivered by their opposite and same gender avatar, respectively. Skin conductance was maximal when taboo touches were delivered by female avatars. Our study shows that IVR may trigger realistic experiences and ultimately allow the direct exploration of sensitive societal and individual issues that can otherwise be explored only through imagination