Balance effects of tactile stimulation at the foot

Balance relies on several types of sensory information, including somatosensory senses such as touch and position sense (proprioception). As these senses decline in older adults, there is a question of whether shoes limit somatosensory feedback from the floor. Textured insoles are designed to stimulate the soles of the feet to enhance tactile feedback. Textured insoles have shown balance benefits in some populations, but it is unclear if such tactile stimulation improves a person's balance even in cushioned athletic shoes, which dampen proprioceptive signals. Here we ask whether tactile vs. proprioceptive cues contribute differently to balance control in the healthy somatosensory system. We assessed balance in 20 healthy young adults under four footwear conditions: cushioned shoes with regular insoles, cushioned shoes with textured insoles, barefoot, and minimalist shoes. Each condition was evaluated using the Y-Balance Test (YBT) and the Balance Error Scoring System (BESS), validated tests of dynamic and static balance, respectively. YBT is a dynamic reaching test performed on one leg. The BESS includes various stance conditions with eyes closed. The results showed that footwear influenced dynamic balance only, with textured insoles leading to significantly better performance than barefoot and minimalist shoes did in the YBT. These results suggest that at least for dynamic balance, balance benefits of tactile stimulation from the textured insoles offset any dampening of proprioception caused by the athletic shoes' cushioning. Future research on how these conditions compare in older adults may lead to improved footwear recommendations to reduce fall risk and injuries for that population.     

A system for providing tactile EMG biofeedback

This report describes a flexible and inexpensive biofeedback system for providing discrete pulses against the skin surface at a frequency proportional to the level of activity from selected muscle groups. The primary components consist of a voltage controlled pulse generator and a tactile transducer. Other system capabilities include the production of digital information for recording devices and the providing of pulsed auditory EMG biofeedback. The system may be particularly applicable for the experimental reduction of psychological and muscle tension.     

A tactile stimulation device for measuring two-point and gap discrimination thresholds in humans

A device to measure two-point-discrimination and gap-discrimination thresholds is described. The apparatus is capable of controlled and reliable delivery of forces up to 42.50 g while determining point of skin contact and subsequent depth of skin indentation during threshold determination. Stimulus delivery is controlled by computer software that deactivates a solenoid, allowing a counterbalanced beam with one of two stimulus wheels mounted on its end to rise and stimulate the skin. Depth of skin indentation is recorded by hardware that monitors the output of a photocell reflecting the position of the beam. The apparatus allows complete computer control of all data acquisition and recording.     

A cognitive-behavioral treatment for irritable bowel syndrome using interoceptive exposure to visceral sensations

BackgroundIrritable bowel syndrome (IBS) is a chronic and debilitating medical condition with few efficacious pharmacological or psychosocial treatment options available. Evidence suggests that visceral anxiety may be implicated in IBS onset and severity. Thus, cognitive-behavioral treatment (CBT) that targets visceral anxiety may alleviate IBS symptoms.MethodsThe current study examined the efficacy of a CBT protocol for the treatment of IBS which directly targeted visceral sensations. Participants (N = 110) were randomized to receive 10 sessions of either: (a) CBT with interoceptive exposure (IE) to visceral sensations; (b) stress management (SM); or (c) an attention control (AC), and were assessed at baseline, mid-treatment, post-treatment, and follow-up sessions.ResultsConsistent with hypotheses, the IE group outperformed AC on several indices of outcome, and outperformed SM in some domains. No differences were observed between SM and AC. The results suggest that IE may be a particularly efficacious treatment for IBS.ConclusionsImplications for research and clinical practice are discussed.     

Planning sentences while doing other things at the same time: effects of concurrent verbal and visuospatial working memory load

This study investigated to what extent advance planning during sentence production is affected by a concurrent cognitive load. In two picture–word interference experiments in which participants produced subject–verb–object sentences while ignoring auditory distractor words, we assessed advance planning at a phonological (lexeme) and at an abstract–lexical (lemma) level under visuospatial or verbal working memory (WM) load. At the phonological level, subject and object nouns were found to be activated before speech onset with concurrent visuospatial WM load, but only subject nouns were found to be activated with concurrent verbal WM load, indicating a reduced planning scope as a function of type of WM load (Experiment 1). By contrast, at the abstract–lexical level, subject and object nouns were found to be activated regardless of type of concurrent load (Experiment 2). In both experiments, sentence planning had a more detrimental effect on concurrent verbal WM task performance than on concurrent visuospatial WM task performance. Overall, our results suggest that advance planning at the phonological level is more affected by a concurrently performed verbal WM task than advance planning at the abstract–lexical level. Also, they indicate an overlap of resources allocated to phonological planning in speech production and verbal WM.     

A system for the assessment of human performance in concurrent verbal and manual control tasks

A multipurpose laboratory system incorporating a voice interactive terminal and graphic display system is described. The facility is designed to investigate some aspects of human performance on concurrent verbal and tracking tasks. The results of a pilot study showing decrements in dual-task performance are reported.     

Three-year-olds understand appearance and reality--just not about the same object at the same time

Young children struggle in the classic tests of appearance versus reality. In the current Study 1, 3-year-olds had to determine which of 2 objects (a deceptive or a nondeceptive one) an adult requested when asking for the "real X" versus "the one that looks like X." In Study 2, children of the same age had to indicate what a single deceptive object (e.g., a chocolate-eraser) looked like and what it really was by selecting one of two items that represented this object's appearance (a chocolate bar) or identity (a regular eraser). Children were mainly successful in Study 1 but not in Study 2. The findings are discussed with a focus on young children's difficulty with "confronting" perspectives, which may be involved in their struggles with a number of classic theory of mind tasks.     

A modular,computer-controlled system for olfactory stimulation in the MRI environment

Although the cerebral networks involved in sensory perception are of general interest in neuroscience, registration of the effects of olfactory stimulation, especially in a magnetic resonance imaging (MRI) environment, presents particular problems and constraints. This article presents details of a reliable and portable system for olfactory stimulation that is modular in design and based on microcontroller technology. It has the following characteristics: (1)?It is under software control; (2)?the presentation of olfactory stimulation can be synchronized with respiration; (3)?it can be manually controlled; and (4)?it is fully compatible with an MRI environment. The principle underlying this system is to direct an odor to the subject’s nostrils by switching airflow to different odor diffusers. The characteristics of this system were established using (1)?ultraviolet (UV) spectroscopy, to measure its response time, and (2)?gas chromatography, to measure the repeatability of odor presentation in terms of gas concentration. A response time of 200?± 25 ms was obtained for the system, and the standard deviations of the gas concentration delivered during stimulation ranged from 1.5% to 22%, depending on the odor, the airflow, and the dilution of the odor used. Since it is portable, controlled by software, and reliable, on the basis of the results we obtained, this system will lend itself to a wide range of applications in olfactory neuroscience.     

Effects of tactile stimulation on low and very low birthweight infants during the first week of life

Thirty-one low and very low birthweight infants were given tactile stimulation during the first week of life. Compared with the control group of 35 they showed less weight loss. When stimulation was started within the first 48 hours, there was significantly less weight loss than when it was started in the interval 49 to 120 hours. Gratitude is due also to the High Wycombe General Hospital, the Ashford (Middlesex) Clinic, Queen Charlotte’s Hospital for Women, the South London Hospital, and particularly St. George’s Hosptial (Tooting) for support and for access to their facilities; without them, and the participation of the mothers and their babies, this work could not have been accomplished.     

Abstraction of tactile properties by individuals with autism and Down syndrome using a picture‐based communication system

The present study evaluated the efficacy of a set of procedures for bringing tact extensions of abstract tactile properties under stimulus control. Two participants with disabilities who communicated via a picture‐based communication system received reinforcement for tacts of tactile properties of four wet/dry and four hard/soft stimuli. Test trials were conducted to evaluate the extent to which the participants' correct responding generalized to novel stimuli with the same tactile properties. The results suggest that the procedures were effective in bringing tact extensions of abstract tactile properties under stimulus control. Both participants' correct responding generalized to a set of novel stimuli. Mastery level responding to training and test targets maintained for 2 weeks following training. The results provide further evidence supporting the use of DTT to teach stimulus abstraction to nonvocal verbal individuals who use augmentative forms of communication.     

A systematic investigation of same and cross modality priming using written and spoken responses

Effects of presentation modality and response format were investigated using visual and auditory versions of the word stem completion task. Study presentation conditions (visual, auditory, non-studied) were manipulated within participants, while test conditions (visual/written, visual/spoken, auditory/written, auditory/spoken, recall-only) were manipulated between participants. Results showed evidence for same modality and cross modality priming on all four word stem completion tasks. Words from the visual study list led to comparable levels of priming across all test conditions. In contrast, words from the auditory study list led to relatively low levels of priming in the visual/written test condition and high levels of priming in the auditory/spoken test condition. Response format was found to influence priming performance following auditory study in particular. The findings confirm and extend previous research and suggest that, for implicit memory studies that require auditory presentation, it may be especially beneficial to use spoken rather than written responses.     

A comparison of tactile spatial sensitivity on the palm and fingerpad

Studies of tactile spatial pattern perception have, for the most part, been carried out using the fingerpad. On the basis of these studies, models have been developed linking spatial pattern identification and resolution with underlying neural structures. It has been suggested that with appropriate scaling, these models would apply to the processing of spatial patterns presented to other sites on the body. Spatial sensitivity was examined on another site on the body, the palm, using two measures, letter identification and grating orientation. The results from these measures were compared with results from similar studies conducted on the fingerpad and with estimates of the density of innervation of the fingerpad and palm. To produce levels of performance similar to those on the fingerpad required letters on the palm 50 mm in height, seven to nine times larger than those used on the fingerpad. Gratings had to be six to more than seven times larger on the palm to produce the same levels of performance achieved on the fingerpad. For the two types of receptor systems sensitive to spatial information, the ratio of density of innervation between the fingerpad and the palm is estimated to be 5.7:1 and 8.8:1. Performance of spatial tasks on the palm can be predicted quantitatively from fingerpad data with a moderate degree of accuracy. Qualitative comparisons between the palm and fingerpad data indicate that spatial patterns are processed similarly at the two sites.     

The effects of fine motor movement and tactile stimulation on the math problem solving of students with attention problems

This study evaluated the effectiveness of fine motor physical activity with tactile stimulation during two conditions of math problem solving, visual and auditory. Eight 4th and 5th grade students with attention problems participated. Using an alternating treatments design, students solved as many math story problems as they could, presented on worksheets or verbally during two conditions, with and without tactile stimulation during 20 min. Motor behavior, recorded from videotape, and number of correctly completed word problems were measured. Results suggest that fine motor manipulation of a tactile stimulation object reduced excessive motor movement and increased task completion of students with attention problems.     

Letter identification declines with increasing retinal eccentricity at the same rate for normal and dyslexic readers

It has recently been claimed (Geiger & Lettvin, 1987; Perry, Dember, Warm, & Sacks, 1989) that the acuity/eccentricity function is flatter in dyslexics than in normal subjects, with dyslexics showing better performance in the periphery and worse performance at fixation. In these studies, all target letters were presented to the right of fixation, a procedural flaw inviting subjects to optimize performance by directing attention and/or gaze to the right of the designated fixation point. It is suggested that dyslexic and normal readers may differ in the degree to which they might adopt the optimal strategy in this situation. To overcome this problem, target letters were briefly presented at 16 randomly intermixed locations derived from the orthogonal combination of four eccentricities and four directions from fixation (above, below, right, left). The accuracy of letter identification declined with increasing eccentricity at the same rate for good and poor adult readers and dyslexic teenagers. This finding provides no support for the view that the acuity/eccentricity function might vary with and possibly cause differences in reading level.