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1.
Disabil Rehabil Assist Technol ; : 1-10, 2024 May 07.
Article in English | MEDLINE | ID: mdl-38712763

ABSTRACT

This study investigates the functionality and feasibility of a novel smart seat cushion system designed for wheelchair users with spinal cord injuries. The cushion, equipped with air cells that serve as both sensors and actuators, was tested on 24 participants for its real-time pressure mapping, automated pressure redistribution, and pressure offloading functions. A commercial pressure mat was concurrently used to validate the cushion's pressure modulation functions. Additionally, the perceived comfort of the cushion was evaluated using General Discomfort Assessment (GDA) and Discomfort Intensity (DIS) scores, which provided insights into participants' overall comfort and discomfort levels. Real-time pressure profiles generated by the cushion resembled commercial pressure mat readings. During tests with individuals with spinal cord injury, the cushion was able to dynamically generate and display the real-time pressure profile of a seated individual with strong precision (correlation to commercial pressure mat: r ranging from 0.76 to 0.88), providing effective input into pressure modulation functions. Pressure redistribution algorithms eliminated peak pressure and reduced the overall pressure at the interface. Pressure offloading algorithms automatically identified the regions with the highest interface pressure and subsequently relieved the pressure from those areas. User feedback showed that the cushion was comfortable after redistribution and offloading. This work demonstrated the feasibility of an advanced smart seat cushion system for wheelchair users with spinal cord injuries. The cushion was capable of redistributing pressure evenly across the seating surface, ensuring user's comfort. Additionally, it identifies and eliminates high-pressure points, further improving comfort and reducing the risk of pressure injuries.


Majority of wheelchair users acquire pressure injuries in their lifetime, where the magnitude and duration of sitting interface pressure are major contributing factors to develop pressure injuries.Compliant cushions and frequent weight shifting can reduce the magnitude and duration of sitting interface pressure; however, the long-term effectiveness of these cushions and the user's lack of compliance to the weight shifting protocols impact their efficacy drastically.An automated cushion system that can reduce the magnitude of the pressure based on the user's current pressure profile and offload pressure from vulnerable areas would improve the effectiveness of the cushion and compensate for poor adherence to weight shifting protocols.Automated solutions will significantly improve the quality of care provided to wheelchair users and reduce the risk of developing pressure injuries.

2.
Autism ; 21(7): 881-895, 2017 10.
Article in English | MEDLINE | ID: mdl-27368350

ABSTRACT

One of the key diagnostic criteria for autism spectrum disorder includes impairments in social interactions. This study compared the extent to which boys with high-functioning autism and typically developing boys "value" engaging in activities with a parent or alone. Two different assessments that can empirically determine the relative reinforcing value of social and non-social stimuli were employed: paired-choice preference assessments and progressive-ratio schedules. There were no significant differences between boys with high-functioning autism and typically developing boys on either measure. Moreover, there was a strong correspondence in performance across these two measures for participants in each group. These results suggest that the relative reinforcing value of engaging in activities with a primary caregiver is not diminished for children with autism spectrum disorder.


Subject(s)
Autistic Disorder/psychology , Parent-Child Relations , Reinforcement, Psychology , Social Behavior , Autism Spectrum Disorder/psychology , Case-Control Studies , Child , Humans , Interpersonal Relations , Male , Parents
3.
Psychol Rec ; 66(2): 301-308, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27182088

ABSTRACT

This study examined whether gambling behavior under conditions of diminishing returns differed between participants with histories of contingent (CD group) and noncontingent (NCD group) token delivery. In Phase 1, CD participants accrued tokens by correctly completing a discrimination task; for NCD participants, token accrual was yoked to token delivery of CD participants. In Phase 2, participants could choose to gamble their tokens or end the experiment and exchange their tokens for money. During the gambling task, participants could bet one token per trial. The probability of losses began at 10% and increased incrementally across blocks of 10 trials up to 100%. Overall, participants in the CD group gambled on fewer trials than participants in the NCD group. Costs of token accrual during Phase 1, in terms of number of trials and duration, showed a positive correlation with net tokens for the CD group but not the NCD group. Results are consistent with previous research demonstrating the value-enhancing effects of both prior contingent delivery and effort, and offer evidence that these histories influence sensitivity to loss.

4.
Curr Opin Behav Sci ; 8: 220-225, 2016 Apr.
Article in English | MEDLINE | ID: mdl-27019863

ABSTRACT

Through an interdisciplinary perspective integrating behavior, neurobiology and evolution, we present a cognitive framework underpinning the development of 'time in mind' in animals (phylogeny) and humans (ontogeny). We distinguish between conscious processing of events immediately available (in the present) to those that are hypothetical (in the past or future). The former is present in animals and neonates, whereas the latter emerges later in phylogeny and ontogeny (around 4 years of age in humans) and is related to the development of episodic memory (expanded working memory, complex actions, social-cognitive abilities). We suggest that forms of temporal representation that rely upon current bodily sensation across time, space, and action (through embodied interoceptive and motor systems) may be critical causal factors for the evolution of mental time travel.

5.
Annu Rev Psychol ; 65: 743-71, 2014.
Article in English | MEDLINE | ID: mdl-24050187

ABSTRACT

Humans share with other animals an ability to measure the passage of physical time and subjectively experience a sense of time passing. Subjective time has hallmark qualities, akin to other senses, which can be accounted for by formal, psychological, and neurobiological models of the internal clock. These include first-order principles, such as changes in clock speed and how temporal memories are stored, and second-order principles, including timescale invariance, multisensory integration, rhythmical structure, and attentional time-sharing. Within these principles there are both typical individual differences--influences of emotionality, thought speed, and psychoactive drugs--and atypical differences in individuals affected with certain clinical disorders (e.g., autism, Parkinson's disease, and schizophrenia). This review summarizes recent behavioral and neurobiological findings and provides a theoretical framework for considering how changes in the properties of the internal clock impact time perception and other psychological domains.


Subject(s)
Attention , Individuality , Mental Disorders/psychology , Time Perception , Humans , Time
6.
Brain ; 135(Pt 3): 656-77, 2012 Mar.
Article in English | MEDLINE | ID: mdl-21921020

ABSTRACT

Distortions in time perception and timed performance are presented by a number of different neurological and psychiatric conditions (e.g. Parkinson's disease, schizophrenia, attention deficit hyperactivity disorder and autism). As a consequence, the primary focus of this review is on factors that define or produce systematic changes in the attention, clock, memory and decision stages of temporal processing as originally defined by Scalar Expectancy Theory. These findings are used to evaluate the Striatal Beat Frequency Theory, which is a neurobiological model of interval timing based upon the coincidence detection of oscillatory processes in corticostriatal circuits that can be mapped onto the stages of information processing proposed by Scalar Timing Theory.


Subject(s)
Cognition Disorders/physiopathology , Cognition Disorders/psychology , Time Perception/physiology , Attention Deficit Disorder with Hyperactivity/physiopathology , Attention Deficit Disorder with Hyperactivity/psychology , Autistic Disorder/physiopathology , Autistic Disorder/psychology , Humans , Information Theory , Memory/physiology , Neuropsychological Tests , Parkinson Disease/physiopathology , Parkinson Disease/psychology , Psychomotor Performance/physiology , Psychophysics , Schizophrenic Psychology
7.
J Appl Behav Anal ; 44(3): 543-58, 2011.
Article in English | MEDLINE | ID: mdl-21941384

ABSTRACT

This study examined how the amount of effort required to produce a reinforcer influenced subsequent preference for, and strength of, that reinforcer in 7 individuals with intellectual disabilities. Preference assessments identified four moderately preferred stimuli for each participant, and progressive-ratio (PR) analyses indexed reinforcer strength. Stimuli were then assigned to one of four conditions for 4 weeks: fixed-ratio (FR) 1 schedule, escalating FR schedule, yoked noncontingent (NCR) delivery, and restricted access. Preference assessments and PR schedules were then repeated to examine changes in selection percentages and PR break points. Selection percentages decreased for all NCR stimuli but increased for most of the restricted stimuli. There were no systematic changes in selection percentages for either of the contingent stimuli. Break points increased, on average, for all conditions, but the increase was highest for the restricted stimuli and lowest for the NCR stimuli. These results are discussed in relation to recent basic research addressing the influence of effort on stimulus value.


Subject(s)
Behavior Therapy/methods , Developmental Disabilities/rehabilitation , Reinforcement Schedule , Adolescent , Adult , Child , Decision Making , Developmental Disabilities/psychology , Female , Humans , Male , Paired-Associate Learning , Young Adult
9.
Am J Intellect Dev Disabil ; 116(2): 165-78, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21381951

ABSTRACT

Perception of time, in the seconds to minutes range, is not well characterized in autism. The required interval timing system (ITS) develops at the same stages during infancy as communication, social reciprocity, and other cognitive and behavioral functions. The authors used two versions of a temporal bisection procedure to study the perception of duration in individuals with autism and observed quantifiable differences and characteristic patterns in participants' timing functions. Measures of timing performance correlated with certain autism diagnostic and intelligence scores, and parents described individuals with autism as having a poor sense of time. The authors modeled the data to provide a relative assessment of ITS function in these individuals. The implications of these results for the understanding of autism are discussed.


Subject(s)
Autistic Disorder/psychology , Time Perception/physiology , Adolescent , Child , Computer Simulation , Discrimination Learning , Female , Humans , Intelligence Tests , Judgment , Learning , Male , Models, Psychological , Neuropsychological Tests , Psychomotor Performance/physiology , Psychophysics
10.
Front Integr Neurosci ; 6: 7, 2011 Oct 14.
Article in English | MEDLINE | ID: mdl-22408612

ABSTRACT

Estimations of time and number share many similarities in both non-humans and man. The primary focus of this review is on the development of time and number sense across infancy and childhood, and neuropsychological findings as they relate to time and number discrimination in infants and adults. Discussion of these findings is couched within a mode-control model of timing and counting which assumes time and number share a common magnitude representation system. A basic sense of time and number likely serves as the foundation for advanced numerical and temporal competence, and aspects of higher cognition-this will be discussed as it relates to typical childhood, and certain developmental disorders, including autism spectrum disorder. Directions for future research in the developmental neuroscience of time and number (NEUTIN) will also be highlighted.

11.
J Exp Psychol Anim Behav Process ; 36(3): 402-8, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20658871

ABSTRACT

In reinforcer-selective transfer, Pavlovian stimuli that are predictive of specific outcomes bias performance toward responses associated with those outcomes. Although this phenomenon has been extensively examined in rodents, recent assessments have extended to humans. Using a stock market paradigm adults were trained to associate particular symbols and responses with particular currencies. During the first test, individuals showed a preference for responding on actions associated with the same outcome as that predicted by the presented stimulus (i.e., a reinforcer-selective transfer effect). In the second test of the experiment, one of the currencies was devalued. We found it notable that this served to reduce responses to those stimuli associated with the devalued currency. This finding is in contrast to that typically observed in rodent studies, and suggests that participants in this task represented the sensory features that differentiate the reinforcers and their value during reinforcer-selective transfer. These results are discussed in terms of implications for understanding associative learning processes in humans and the ability of reward-paired cues to direct adaptive and maladaptive behavior.


Subject(s)
Conditioning, Classical/physiology , Conditioning, Operant/physiology , Decision Making/physiology , Reinforcement, Psychology , Transfer, Psychology/physiology , Adult , Extinction, Psychological , Female , Humans , Male , Middle Aged , Reward , Young Adult
12.
J Neurodev Disord ; 2(3): 149-164, 2010 Sep 01.
Article in English | MEDLINE | ID: mdl-21274406

ABSTRACT

Neurocognitive assessment in individuals with intellectual disabilities requires a well-validated test battery. To meet this need, the Arizona Cognitive Test Battery (ACTB) has been developed specifically to assess the cognitive phenotype in Down syndrome (DS). The ACTB includes neuropsychological assessments chosen to 1) assess a range of skills, 2) be non-verbal so as to not confound the neuropsychological assessment with language demands, 3) have distributional properties appropriate for research studies to identify genetic modifiers of variation, 4) show sensitivity to within and between sample differences, 5) have specific correlates with brain function, and 6) be applicable to a wide age range and across contexts. The ACTB includes tests of general cognitive ability and prefrontal, hippocampal and cerebellar function. These tasks were drawn from the Cambridge Neuropsychological Testing Automated Battery (CANTAB) and other established paradigms. Alongside the cognitive testing battery we administered benchmark and parent-report assessments of cognition and behavior. Individuals with DS (n=74, ages 7-38 years) and mental age (MA) matched controls (n=50, ages 3-8 years) were tested across 3 sites. A subsample of these groups were used for between-group comparisons, including 55 individuals with DS and 36 mental age matched controls. The ACTB allows for low floor performance levels and participant loss. Floor effects were greater in younger children. Individuals with DS were impaired on a number ACTB tests in comparison to a MA-matched sample, with some areas of spared ability, particularly on tests requiring extensive motor coordination. Battery measures correlated with parent report of behavior and development. The ACTB provided consistent results across contexts, including home vs. lab visits, cross-site, and among individuals with a wide range of socio-economic backgrounds and differences in ethnicity. The ACTB will be useful in a range of outcome studies, including clinical trials and the identification of important genetic components of cognitive disability.

13.
J Appl Behav Anal ; 42(3): 729-33, 2009.
Article in English | MEDLINE | ID: mdl-20190936

ABSTRACT

The current study examined whether stimuli of different preference levels would be associated with different amounts of work maintained by the stimuli, as determined through progressive-ratio schedule break points. Using a paired-choice preference assessment, stimuli were classified as high, moderate, or low preference for 4 individuals with developmental disabilities. The stimuli were then tested three times each using a progressive-ratio schedule (step size of 1; the break-point criterion was 1 min). In 10 of 12 possible comparisons, higher preference stimuli produced larger break points than did lower preference stimuli.


Subject(s)
Choice Behavior/physiology , Mental Disorders/psychology , Reinforcement Schedule , Reinforcement, Psychology , Adolescent , Association Learning/physiology , Child , Female , Humans , Male , Neuropsychological Tests , Young Adult
14.
J Exp Psychol Anim Behav Process ; 32(3): 307-13, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16834497

ABSTRACT

In 2 experiments, rats received preexposure to 2 compound contexts: AB and CD for the congruent group and AC and BD for the incongruent group. Subsequently, all rats received a configural discrimination in which separate placement in contexts A or B indicated that presentations of stimulus X would be followed by food and presentations of Y would not, and separate placement in contexts C and D indicated that Y would be followed by food and X would not. In both experiments, rats in the congruent group acquired the conditional discrimination more rapidly than those in the incongruent group. These results are inconsistent with conventional associative accounts of either stimulus preexposure effects or configural learning and instead provide support for a connectionist account.


Subject(s)
Conditioning, Psychological/physiology , Discrimination, Psychological/physiology , Learning/physiology , Transfer, Psychology/physiology , Analysis of Variance , Animals , Behavior, Animal , Cues , Male , Models, Psychological , Rats , Time Factors
15.
J Exp Psychol Anim Behav Process ; 31(3): 363-7, 2005 Jul.
Article in English | MEDLINE | ID: mdl-16045390

ABSTRACT

The results of a recent study have provided direct support for the suggestion that conditional learning in rats is best characterized by a 3-layer connectionist network (M. J. Allman, J. Ward-Robinson, & R. C. Honey, 2004). In the 2 experiments reported here, rats were used to investigate the nature of the changes that occur when a stimulus compound is presented, whose components activate hidden units associated with food and no food, and either food or no food is presented. The results of both experiments, while controlling for the possible contribution of associations between these hidden units (within-layer links), provide evidence that the distribution of associative change between units in the hidden layer that are activated by the stimulus compound and those in the output layer (between-layer links) are unequal. They also indicate that associative change is more marked on trials on which no food was presented than on trials on which food was presented.


Subject(s)
Association Learning/physiology , Conditioning, Classical/physiology , Discrimination Learning/physiology , Neural Networks, Computer , Analysis of Variance , Animals , Behavior, Animal , Male , Rats
16.
J Exp Psychol Anim Behav Process ; 30(2): 118-28, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15078121

ABSTRACT

Three experiments with rats investigated how the associative strengths of the representations that underlie conditional learning change when they are conditioned in compound. The results of each experiment suggest that the representation whose associative strength is most discrepant from the asymptote supported by the outcome of the trial undergoes the greatest change in associative strength. These results parallel those from simple Pavlovian conditioning (e.g., R. A. Rescorla, 2000). are inconsistent with unique-cue and configural accounts of conditional learning, and support a connectionist analysis of learning in which a "winner-takes-all" rule applies to the hidden units that can be activated and acquire associative strength at a given point in time.


Subject(s)
Association Learning , Conditioning, Classical , Discrimination Learning , Analysis of Variance , Animals , Cues , Male , Pattern Recognition, Automated , Rats , Rats, Inbred Strains
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