Finger Localization Research Articles

B - 51 Are my Constructs Bass-Ackwards? A Hierarchical Approach to Neuropsychological Factors in Traumatic Brain Injury

Abstract Objective This study examined neuropsychological measures within a hierarchical framework in a traumatic brain injury (TBI) sample. Methods 270 individuals (M = 32 years old, SD = 14.8; 70% male, 94% white) with mixed TBI severity (73.7% mild TBI) completed the Meyers Neuropsychological Battery (MNB). Principal Components Analyses (PCAs) were conducted using Goldberg’s (2006) “bass-ackwards” hierarchical approach commonly used to evaluate “stratum” in personality and psychopathology. This involves an iterative top-down approach extracting a single general factor, then using the same data to extract two factors, then three factors, and continues as long as theoretically feasible. Extracted factors are saved as factor scores and correlated to reveal pathways between stratum. Results Iterative PCAs revealed a 4-stratum model. The first unrotated principal component (FUPC) was defined by loadings for Arithmetic, AVLT, RCFT, and Block Design. The second stratum factors were defined by AVLT and BNT (factor 1) and RCFT and Block Design (factor 2). The third stratum was defined by RCFT, Block Design, and Finger Localization nondominant (factor 1); Information and BNT (factor 2); and AVLT, Coding, and Finger Tapping dominant (factor 3). Stratum 4 was RCFT and Block Design (factor 1); AVLT (factor 2); Sentence Repetition, Similarities, and Information (factor 3); and Finger Tapping bilateral, Coding, and Trails Making Test (factor 4). Correlational pathways between factors ranged from 0.50 to 0.98. Conclusion Factors at lower stratum generally aligned with functions for cortical lobes. For example, Stratum 4 can be conceptualized as right temporoparietal (factor 1), left temporal (factor 2), left frontotemporal (factor 3), and bilateral frontal (factor 4).

Compromised interhemispheric transfer of information partially mediates cognitive function deficits in adolescents with fetal alcohol syndrome.

Prenatal alcohol exposure (PAE) has been associated with compromised interhemispheric transfer of tactile stimuli in childhood and structural changes to the corpus callosum (CC). In this study, we used a finger localization task (FLT) to investigate whether interhemispheric transfer deficits persist in adolescence; whether effects of PAE on perceptual reasoning, working memory, and executive function are mediated by deficits in interhemispheric transfer of information; and whether CC size in childhood predicts FLT performance in adolescence. Participants, aged 16 to 17years, were from the Cape Town Longitudinal Cohort, whose mothers were recruited during pregnancy and interviewed regarding their alcohol use using the timeline follow-back method. Diagnoses of fetal alcohol syndrome (FAS) and partial FAS (PFAS) were determined by two expert dysmorphologists; nonsyndromal exposed children were designated as heavily exposed (HE); those born to abstainers or light drinkers, as controls. The FLT was administered to 74 participants (12 FAS, 16 PFAS, 14 HE and 32 controls). CC size at age 9 to 12years was available for 35 participants (7 FAS, 13 PFAS, 5 HE and 10 control). Although the degree of PAE was similar in the FAS, PFAS, and HE groups, only the adolescents with FAS showed more transfer-related errors than controls in conditions in which one finger was stimulated. FLT performance mediated the effects of FAS on perceptual reasoning and executive function. In the subsample for which neuroimaging data from childhood were available, there was an association among adolescents with PAE of smaller CC volumes with more transfer-related errors on the one-finger/hand hidden condition, suggesting that CC damage previously seen in childhood continues to impact function through adolescence. This study provides evidence of compromised interhemispheric transfer of information in adolescents with FAS, while those with PFAS or heavy exposed nonsyndromal individuals are apparently spared. It is the first to show that PAE effects on important aspects of cognitive function are partially mediated by deficits in the interhemispheric transfer of information.

Object Localization and Tracking System Using Multiple Ultrasonic Sensors with Newton–Raphson Optimization and Kalman Filtering Techniques

In this paper, an object localization and tracking system is implemented with an ultrasonic sensing technique and improved algorithms. The system is composed of one ultrasonic transmitter and five receivers, which uses the principle of ultrasonic ranging measurement to locate the target object. This system has several stages of locating and tracking the target object. First, a simple voice activity detection (VAD) algorithm is used to detect the ultrasonic echo signal of each receiving channel, and then a demodulation method with a low-pass filter is used to extract the signal envelope. The time-of-flight (TOF) estimation algorithm is then applied to the signal envelope for range measurement. Due to the variations of position, direction, material, size, and other factors of the detected object and the signal attenuation during the ultrasonic propagation process, the shape of the echo waveform is easily distorted, and TOF estimation is often inaccurate and unstable. In order to improve the accuracy and stability of TOF estimation, a new method of TOF estimation by fitting the general (GN) model and the double exponential (DE) model on the suitable envelope region using Newton–Raphson (NR) optimization with Levenberg–Marquardt (LM) modification (NRLM) is proposed. The final stage is the object localization and tracking. An extended Kalman filter (EKF) is designed, which inherently considers the interference and outlier problems of range measurement, and effectively reduces the interference to target localization under critical measurement conditions. The performance of the proposed system is evaluated by the experimental evaluation of conditions, such as stationary pen localization, stationary finger localization, and moving finger tracking. The experimental results verify the performance of the system and show that the system has a considerable degree of accuracy and stability for object localization and tracking.

Body structural representation in schizotypy

A deficient sense of self, typically observed in schizophrenia spectrum disorders, is often accompanied by abnormalities in bodily perception and awareness. These abnormalities are seemingly among the most powerful predictive factors for the onset of schizophrenic illnesses. According to the hypothesis of the psychosis continuum, high schizotypal traits in the general population may be characterized by a progressive sense of detachment from one's lived body. Building upon previous research that found an abnormal Body Structural Representation (BSR) in individuals with schizophrenia, this study aims to extend these findings to schizotypy. To investigate this, we utilized the Finger Localization Task (FLT), in which participants must identify the finger touched by the experimenter, and the In Between Task (IBT), in which two fingers are touched and participants must specify the number of fingers in between the two stimulated fingers. We found that individuals with high schizotypy were significantly less accurate than individuals with low schizotypy in determining the spatial configuration of their own fingers relative to each other. Most significantly, performances on both tasks were negatively correlated with the score on the Dissociative Experiences Scale (DES). These findings support the hypothesis that the progressive loss of one's sense of self is associated with abnormal bodily experiences and dissociative symptomatology which may represent a potential marker for schizophrenia proneness.

RFaNet: Receptive Field-Aware Network with Finger Attention for Fingerspelling Recognition Using a Depth Sensor

Automatic fingerspelling recognition tackles the communication barrier between deaf and hearing individuals. However, the accuracy of fingerspelling recognition is reduced by high intra-class variability and low inter-class variability. In the existing methods, regular convolutional kernels, which have limited receptive fields (RFs) and often cannot detect subtle discriminative details, are applied to learn features. In this study, we propose a receptive field-aware network with finger attention (RFaNet) that highlights the finger regions and builds inter-finger relations. To highlight the discriminative details of these fingers, RFaNet reweights the low-level features of the hand depth image with those of the non-forearm image and improves finger localization, even when the wrist is occluded. RFaNet captures neighboring and inter-region dependencies between fingers in high-level features. An atrous convolution procedure enlarges the RFs at multiple scales and a non-local operation computes the interactions between multi-scale feature maps, thereby facilitating the building of inter-finger relations. Thus, the representation of a sign is invariant to viewpoint changes, which are primarily responsible for intra-class variability. On an American Sign Language fingerspelling dataset, RFaNet achieved 1.77% higher classification accuracy than state-of-the-art methods. RFaNet achieved effective transfer learning when the number of labeled depth images was insufficient. The fingerspelling representation of a depth image can be effectively transferred from large- to small-scale datasets via highlighting the finger regions and building inter-finger relations, thereby reducing the requirement for expensive fingerspelling annotations.

Callosal abnormalities, altered cortisol levels, and neurocognitive deficits associated with early maltreatment among adolescents: A voxel-based diffusion-tensor imaging study.

IntroductionNeuroimaging studies have shown callosal abnormalities among maltreated subjects, but little is known about the functional and neurobiological correlates of these supposed developmental alterations. The aim of this study was to investigate childhood maltreatment (CM), neurocognitive functioning, cortisol levels, and corpus callosum (CC) integrity among adolescents.MethodsOne hundred and seven subjects underwent magnetic resonance imaging (MRI) with voxel‐based diffusion‐tensor imaging (DTI) and the Crossed Finger Localization Test (CFLT). Psychopathology was investigated with the Schedule for Affective Disorders and Schizophrenia (K‐SADS‐PL); CM was detailed by the Childhood Trauma Questionnaire (CTQ), and salivary cortisol levels were measured by immunoassay.ResultsHigher levels of CM were associated with current lower CFLT scores, mainly in the CROSSED condition, involving interhemispheric communication of sensorimotor information (p < .05) and with reduced fractional anisotropy (FA) in the splenium of the CC (p < .01). Deficits in the CFLT were also associated with higher cortisol levels (p < .05).ConclusionThe association among CM, neuropsychological abnormalities, callosal microstructure alterations, and cortisol levels suggests an altered pattern of brain interhemispheric connectivity among maltreated adolescents. Further studies are needed to investigate the extent to which these sensorimotor deficits and abnormal cortisol levels may be possible mediators of negative neurodevelopmental trajectories and adult psychopathology.

Body representations and basic symptoms in schizophrenia

Patients with schizophrenia report a wide range of anomalous body experiences. According to the basic symptom model of schizophrenia, disturbances of body perception and awareness are among the most powerful predictors of the changes in the subjective experience of the self in schizophrenia. In this study we first investigated the body structural representation (BSR), a specific aspect of body awareness, and its association to basic symptoms in patients with schizophrenia. Using a finger localization task, we found that patients are significantly less accurate than healthy controls when asked to identify pairs of fingers touched by the experimenter, when the hand is hidden from view. Most importantly, patients' performance at the finger localization task was negatively associated to basic symptoms: the worse the individual accuracy, the higher the SPI-A total score. Moreover, the accuracy at the finger localization task was also negatively correlated with the malleability of the sense of body ownership: the less the individual ability to localize fingers, the stronger the rubber hand illusion. These results are in agreement with the idea that self-disorders in schizophrenia reveal a disconnectedness that can be regarded as a problem of disembodiment and traced back to abnormal body experiences.

Tactile Discrimination, Praxis and Cognitive Impulsivity in ADHD Children: A Cross-Sectional Study.

Background: The study of attention deficit hyperactivity disorder (ADHD) has traditionally focused on deficit of inhibitory control and cognitive impulsivity. However, the pathophysiology of ADHD has also been associated with the somatosensory cortex. The aim of this study was to explore if there were differences in tactile discrimination and praxis between neurotypical and ADHD children and whether these differences could be explained by cognitive impulsivity. Methods: A cross-sectional study was conducted. The sample comprised 74 children aged 7 to 11 years divided in two groups: 43 with neurotypical development, 31 with ADHD. To assess tactile discrimination, the finger localization and the graphestesia tests were used. Praxis was assessed with the Kaufman Assesment Battery for Children (K-ABC) hand movement subtest, the action program and the Zoo Map subtests of the Behavioral Assessment of Dysexecutive Syndrome, and the complex figure of Rey–Osterrieth test (ROCF). Cognitive impulsivity was assessed using the Magallanes Computerized Impulsivity Scale test (EMIC). Results: Children with ADHD showed greater cognitive impulsivity (p = 0.038) and scored lower in Zoo Map (p = 0.023) and hand-movement subtests (p = 0.002), and in ROCF test (p = 0.004). Differences in praxis skills still remained after controlling by gender and cognitive impulsivity. Conclusion: Praxis deficit might have repercussions not only on the characterization of ADHD but also on its treatment.

Inherited epidermolysis bullosa: Case report of finger localization

Inherited epidermolysis bullosa is a rare condition that often present at birth with skin blisters and erosions. They are associated with defective cohesion of the dermis and epidermis. There are 3 principal types: Simple, junctional and dystrophic. The severity of the condition is quite variable. The most severe forms are incompatible with life. The most common types in our country are the severe ones such as the Hallopeau -Siemens subtype. Hands and mucosal areas can develop synechia. We report here a case of dystrophic epidermolysis bullosa in a 27-year-old woman whose finger lesion was managed surgically. This treatment consisted of complete removal of constrictions and adhesions, accompanied by use of a Hueston flap and skin graft to repair the tissue deficit. The patient's clinical course required several repeat operations. This surgery allowed the possible total loss of hand function to be delayed but the inevitable progression of the illness made the treatment somewhat disappointing. Psychosocial implications are very significant in our setting.

Volume reduction of the corpus callosum and its relationship with deficits in interhemispheric transfer of information in recent-onset psychosis

The present study aimed to investigate the presence of corpus callosum (CC) volume deficits in a population-based recent-onset psychosis (ROP) sample, and whether CC volume relates to interhemispheric communication deficits. For this purpose, we used voxel-based morphometry comparisons of magnetic resonance imaging data between ROP ( n = 122) and healthy control ( n = 94) subjects. Subgroups (38 ROP and 39 controls) were investigated for correlations between CC volumes and performance on the Crossed Finger Localization Test (CFLT). Significant CC volume reductions in ROP subjects versus controls emerged after excluding substance misuse and non-right-handedness. CC reductions retained significance in the schizophrenia subgroup but not in affective psychoses subjects. There were significant positive correlations between CC volumes and CFLT scores in ROP subjects, specifically in subtasks involving interhemispheric communication. From these results, we can conclude that CC volume reductions are present in association with ROP. The relationship between such deficits and CFLT performance suggests that interhemispheric communication impairments are directly linked to CC abnormalities in ROP.

Feeling for space or for time: Task-dependent modulation of the cortical representation of identical vibrotactile stimuli

Using functional MRI we examined the task-dependency of brain activation patterns evoked by vibrotactile stimulation. For this purpose, we measured activations after identical stimulation of the fingers of the right hand in three different task conditions: passive attention, localization of the vibrations, and discrimination of temporal noise within the vibrations. Further, we investigated whether, regardless of task demands, the characteristics of the vibrations – periodic versus noisy – had an effect on brain topography. Vibrotactile processing was associated with activation in a variety of cortical areas including contralateral primary somatosensory cortex (SI), bilateral posterior parietal cortex, parietal operculum (second somatosensory cortex, SII), insula, and superior temporal gyrus, as well as ipsilateral middle temporal gyrus, precentral, and middle frontal gyrus. However, identical stimuli evoked different brain activity patterns in different task conditions: significantly stronger activity in the hand representation of SI was found for stimulus localization than for noise detection. In contrast, significantly higher activation for noise detection than for finger localization was found in the thalamus. Activation tended to be lower for noisy stimuli in both hemispheres. Significant stimulus-related differences, however, could be found only in the contralateral postcentral and parietal cortex, particularly during noise discrimination. In summary, in response to vibrotactile stimulation, the level of activation in processing circuits ranging across thalamus and many cortical regions is dictated by the perceptual operation carried out on the vibration. We speculate that different nodes in the network carry signals that can be optimally decoded for either spatial or temporal information and that the degree of activation reflects those nodes’ relative contributions to the decoding process.

Neurophysiological Evidence for Transcallosal Somatosensory Processing in Humans

Interhemispheric information transfer is crucially dependent on the integrity of the corpus callosum (CC). It has been previously shown that the intactness of the posterior body of the CC is relevant for the performance of tactile behavioral tests, i.e. intermanual tasks of tactile finger localization (TFL) and haptic object recognition (HOR) tests. In this study, we aimed at providing neurophysiological evidence of transcallosal somatosensory processing (TCSP) for the first time.

A Tactile Display System for Hand Prostheses to Discriminate Pressure and Individual Finger Localization

No current commercially available myoelectrically controlled prosthetic hands provide conscious sensory feedback to the user. A system aiming at relocation of sensory input from a prosthetic hand equipped with force sensors to the forearm skin of amputees, a tactile display, has been developed and constructed. The system consists of five piezoresistive force sensors or, alternatively, a prosthetic hand equipped with three sensors, five digital servomotors with a lever and a circular plastic disk pushing on the skin, control electronics based on an MSP430 microcontroller and a test application implemented in LabVIEW running on a PC. The tactile display system is intended to be integrated into the socket of a hand prosthesis and used as a conscious sensory feedback system for hand amputees using a myoelectrically controlled hand prosthesis. The system will provide continuous force feedback from sensors in the fingertips of each prosthetic finger and will likely improve the users' controllability and perception of the prosthetic hand. Here we report on tests made on ”a five site” localization discrimination task and three pressure level discrimination tasks on the forearm of live healthy participants (non-amputees) using the LabView application to generate the stimulations. A mean live-linger discrimination accuracy of 86% and a mean three-level pressure discrimination accuracy of 93% were achieved, indicating the system to he a viable method of producing sensory feedback on the level of individual fingers.

Prenatal Alcohol Exposure and Interhemispheric Transfer of Tactile Information: Detroit and Cape Town Findings

Previous research has demonstrated that heavy prenatal alcohol exposure affects the size and shape of the corpus callosum (CC) and compromises interhemispheric transfer of information. The aim of this study was to confirm the previous reports of poorer performance on a finger localization test (FLT) of interhemispheric transfer in a cohort of heavily exposed children and to extend these findings to a cohort of moderately exposed young adults. In Study 1, the FLT was administered to 40 heavily exposed and 23 nonexposed children from the Cape Coloured community of Cape Town, South Africa, who were evaluated for fetal alcohol syndrome (FAS) dysmorphology and growth. Anatomical images of the CC were obtained using structural MRI on a subset of these children. In Study 2, the FLT was administered to a cohort of 85 moderate-to-heavily exposed young adults participating in a 19-year follow-up assessment of the Detroit Prenatal Alcohol Exposure cohort, whose alcohol exposure had been ascertained prospectively during gestation. In Study 1, children with FAS showed more transfer-related errors than controls after adjustment for confounding, and increased transfer-related errors were associated with volume reductions in the isthmus and splenium of the CC. In Study 2, transfer-related errors were associated with quantity of alcohol consumed per occasion during pregnancy. More errors were made if the mother reported binge drinking (> or =5 standard drinks) during pregnancy than if she drank regularly (M > or = 1 drink/day) without binge drinking. These findings confirm a previous report of impaired interhemispheric transfer of tactile information in children heavily exposed to alcohol in utero and extend these findings to show that these deficits are also seen in more moderately exposed individuals, particularly those exposed to binge-like pregnancy drinking.

Language and crossed finger localization in patients with schizophrenia

Language deficits are frequently reported in studies of patients with schizophrenia. The present study sought to test the hypothesis that such deficits are related to callosal function in this group. The FAS test of verbal fluency and Perin's Spoonerisms test of phonological processing were the tests of language. Callosal function was assessed using a Crossed Finger Localisation Test (CFLT), which is a measure of the interhemispheric transfer of somatosensory information. Patients with schizophrenia performed less well than controls on measures of language function, as well as on the CFLT. Significant positive correlations between CFLT performance and language function were present in the patient group, but not the control group. These findings extend on previous studies that report functional abnormalities of the corpus callosum in schizophrenia and are consistent with the hypothesis that language deficits in schizophrenia are related to impaired callosal functioning in this group. However, other explanations cannot be ruled out.

Interhemispheric communication involving multiple tasks: A study of children with dyslexia

The study investigated whether inefficient interhemispheric communication is involved in developmental dyslexia using multiple tasks. A finger localization task, rhyming judgment task, primed lexical decision task, and a visual half-field presentation paradigm were used. Nineteen dyslexic children (mean age = 13.1 years) were compared with 26 chronological age-matched normal children. Although the dyslexic group demonstrated significantly slower and less accurate performance in all three tasks, there was no significant group difference in term of interhemispheric communication. However, priming effects demonstrated by the dyslexic group ( p < .05) further indicate that their reading problems may stem from the word retrieval process from the long term memory.

Dyslexia and across-hands finger localization deficits

Two experiments on finger localization are reported. Experiment 1 compared children who were poor readers with two groups of children matched to poor readers for sex and either age (CA controls) or reading age (RA controls). The participant's hands were kept out of his or her sight in a semi-open box while the fingers of one hand were lightly touched by the experimenter. The participant's task was to indicate, using the thumb of either the same hand (within-hand condition) or the opposite hand (across-hands condition) to respond, the finger(s) which had been touched by the experimenter. Performance was significantly impaired in the across-hands condition compared with the within-hand condition. Experiment 2 was carried out with dyslexic adults and a control group of normal readers. Using the same method of responding as in Experiment 1, a significant deficit in the across-hands condition compared to the within-hand condition was found for both groups. The effect was also obtained for both groups when participants were required to point to the relevant fingers on a photograph of a hand rather than use the thumb of the opposite hand to respond. The results are discussed in relation to the hypothesis of a deficit in inter-hemispheric transfer of tactile information in dyslexia.

Contribution of posterior corpus callosum to the interhemispheric transfer of tactile information

Three total and three partial callosotomy patients underwent neuropsychological testing to evaluate interhemispheric transfer of tactile information. Tactile transfer is required to name objects presented to the left hand, to compare objects held in either hand, and to transfer topological information between hands. Tactile Naming, Same–Different Recognition, and Tactile Finger Localization Tests (intra- and intermanual tasks) were administered as specific tools. Results were compared with previous fMRI data from the same subjects and with the performance of a control group (20 age-matched subjects). Total callosotomy patients performed modestly: mean correct responses were 93% and 30% (right and left hand, respectively) in Tactile Naming; 68% in Same–Different Recognition; 84% and 76% (right and left hand stimulation, respectively) in intermanual Tactile Finger Localization, and 100% in the intramanual task. Partial callosotomy patients achieved 93–100% accuracy: all have an intact splenium, and one, and possibly all, also an intact posterior callosal body. Controls scored 99% in Tactile Naming, both hands, and Same–Different Recognition; 100% in intramanual Tactile Finger Localization; and 96% and 95%, with right and left hand stimulation, respectively, in the intermanual task. Differences between the two callosotomy groups were significant, as were those between total callosotomy patients and controls. The partial callosotomy group scored like the control subjects. Neuropsychological data agree with previous functional findings, further demonstrating that interhemispheric tactile transfer requires posterior corpus callosum integrity.

Interhemispheric Transfer in Children with Heavy Prenatal Alcohol Exposure

Background Prenatal alcohol exposure has long been associated with alterations in brain structure and behavioral changes. The corpus callosum can be affected by heavy prenatal alcohol exposure, and agenesis (absence) of this structure occurs more often in children with fetal alcohol syndrome than in the general population or in other developmentally delayed populations. Although the majority of children with fetal alcohol syndrome do not have agenesis of the corpus callosum, callosal area is reduced in this population, particularly in the anterior and posterior regions. However, the functional implication of these size reductions has not been examined.Methods The current study used a finger localization task to measure the transfer of information across the corpus callosum in children and adolescents with histories of heavy prenatal alcohol exposure and age‐ and sex‐matched controls. In a subset of children, correlational analysis was also conducted between behavioral data and cross‐sectional area of the corpus callosum.Results When compared with nonexposed controls, alcohol‐exposed children made more errors on trials for which information had to cross the corpus callosum (“crossed” trials) than on trials for which it did not (“uncrossed” trials), and they also made more errors as the task increased in complexity. Additionally, correlations with magnetic resonance imaging data in a subset of children revealed that impairment in interhemispheric transfer was related to reductions in the size of the corpus callosum. These correlations were independent of effects expected from the relationship between corpus callosum size and general intellectual functioning alone.Conclusions These findings suggest that children with heavy prenatal alcohol exposure display subtle deficits in the interhemispheric transfer of information in the somatosensory domain. Such deficits in interhemispheric transfer are likely to be related to the myriad of other behavioral and cognitive impairments observed in these children.

Lateralities in Normal Children Ages 3 to 8 and Their Role in Cognitive Performances

The presence and type of correlations between laterality and cognitive skills in normal adults or children remains controversial. This study examines relations between different lateralities, that is, handedness, footedness, eyedness, parental left-handedness, asymmetry of hand skill on a computerized version of the Peg-Moving Task (CPMT) proposed by Annett (1985), and different verbal and nonverbal skills assessed by 13 tasks in 254 normal children, aged 3 to 8 years. Results showed increasing performances with increasing dextrality on the CPMT for 2 tasks involving phonology (Phonological Fluency and Reading Nonwords), 2 tasks involving visual memory and visuospatial skills, and for finger localization. Footedness, eyedness, and parental left-handedness had no significant effect on cognitive performance. The pattern of performance according to the sinistrality-dextrality continuum was highly variable from one cognitive task to the other. The previously mentioned results suggest that relative hand skill is a better correlative of cognitive performance than the usual measures of handedness. Further study is needed to specify the pattern of associations.