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1.
Front Neurosci ; 17: 1193402, 2023.
Article in English | MEDLINE | ID: mdl-37483346

ABSTRACT

Introduction: Auditory verbal hallucinations (AVHs), or hearing non-existent voices, are a common symptom in psychosis. Recent research suggests that AVHs are also experienced by neurotypical individuals. Individuals with schizophrenia experiencing AVHs and neurotypicals who are highly prone to hallucinate both produce false positive responses in auditory signal detection. These findings suggest that voice-hearing may lie on a continuum with similar mechanisms underlying AVHs in both populations. Methods: The current study used a monaural auditory stimulus in a signal detection task to test to what extent experimentally induced verbal hallucinations are (1) left-lateralised (i.e., more likely to occur when presented to the right ear compared to the left ear due to the left-hemisphere dominance for language processing), and (2) predicted by self-reported hallucination proneness and auditory imagery tendencies. In a conditioning task, fifty neurotypical participants associated a negative word on-screen with the same word being played via headphones through successive simultaneous audio-visual presentations. A signal detection task followed where participants were presented with a target word on-screen and indicated whether they heard the word being played concurrently amongst white noise. Results: Results showed that Pavlovian audio-visual conditioning reliably elicited a significant number of false positives (FPs). However, FP rates, perceptual sensitivities, and response biases did not differ between either ear. They were neither predicted by hallucination proneness nor auditory imagery. Discussion: The results show that experimentally induced FPs in neurotypicals are not left-lateralised, adding further weight to the argument that lateralisation may not be a defining feature of hallucinations in clinical or non-clinical populations. The findings also support the idea that AVHs may be a continuous phenomenon that varies in severity and frequency across the population. Studying induced AVHs in neurotypicals may help identify the underlying cognitive and neural mechanisms contributing to AVHs in individuals with psychotic disorders.

2.
Aging Ment Health ; 27(1): 193-202, 2023 01.
Article in English | MEDLINE | ID: mdl-35352597

ABSTRACT

OBJECTIVES: Computer-use behaviours can provide useful information about an individual's cognitive and functional abilities. However, little research has evaluated unaided and non-directed home computer-use. In this proof of principle study, we explored whether computer-use behaviours recorded during routine home computer-use i) could discriminate between individuals with subjective cognitive decline (SCD) and individuals with mild cognitive impairment (MCI); ii) were associated with cognitive and functional scores; and iii) changed over time. METHODS: Thirty-two participants with SCD (n = 18) or MCI (n = 14) (mean age = 72.53 years; female n = 19) participated in a longitudinal study in which their in-home computer-use behaviour was passively recorded over 7-9 months. Cognitive and functional assessments were completed at three time points: baseline; mid-point (4.5 months); and end point (month 7 to 9). RESULTS: Individuals with MCI had significantly slower keystroke speed and spent less time on the computer than individuals with SCD. More time spent on the computer was associated with better task switching abilities. Faster keystroke speed was associated with better visual attention, recall, recognition, task inhibition, and task switching. No significant change in computer-use behaviour was detected over the study period. CONCLUSION: Passive monitoring of computer-use behaviour shows potential as an indicator of cognitive abilities, and can differentiate between people with SCD and MCI. Future studies should attempt to monitor computer-use behaviours over a longer time period to capture the onset of cognitive decline, and thus could inform timely therapeutic interventions.Supplemental data for this article can be accessed online at http://dx.doi.org/10.1080/13607863.2022.2036946.


Subject(s)
Cognitive Dysfunction , Humans , Female , Aged , Male , Longitudinal Studies , Cognition , Recognition, Psychology , Computers , Neuropsychological Tests
3.
Int J Audiol ; 61(6): 463-472, 2022 06.
Article in English | MEDLINE | ID: mdl-34406107

ABSTRACT

OBJECTIVE: The current study aimed to: i) determine the patterns of hearing protection device (HPD) use in early-career musicians, ii) identify barriers to and facilitators of HPD use, and iii) use the Behaviour Change Wheel (BCW) to develop an intervention to increase uptake and sustained use of HPDs. DESIGN: A mixed-methods approach using questionnaires and semi-structured interviews. STUDY SAMPLE: Eighty early-career musicians (age range = 18-26 years; women n = 39), across all categories of musical instrument. RESULTS: 42.5% percent of participants reported using HPDs at least once a week, 35% less than once a week, and 22.5% reported never using HPDs for music-related activities. Six barriers and four facilitators of HPD use were identified. Barriers include the impact of HPDs on listening to music and performing, and a lack of concern about noise exposure. Barriers/facilitators were mapped onto the Theoretical Domains Framework. Following the systematic process of the BCW, our proposed intervention strategies are based on 'Environmental Restructuring', such as providing prompts to increase awareness of noisy settings, and 'Persuasion/Modelling', such as providing credible role models. CONCLUSIONS: For the first time, the present study demonstrates the use of the BCW for designing interventions in the context of hearing conservation.


Subject(s)
Hearing Loss, Noise-Induced , Music , Adolescent , Adult , Ear Protective Devices , Female , Hearing , Hearing Loss, Noise-Induced/etiology , Hearing Loss, Noise-Induced/prevention & control , Humans , Male , Noise , Young Adult
4.
Article in English | MEDLINE | ID: mdl-34948489

ABSTRACT

Earplugs can reduce the risk of hearing loss and tinnitus. However, earplug use during noisy recreational activities is uncommon, and methods for increasing uptake and regular use have had limited efficacy. The aim of the present study was to examine barriers and enablers of ever-performers (e.g., people who have used earplugs) and never-performers (e.g., people who have not used earplugs) to identify targets to inform the content of interventions to increase uptake and regular use of earplugs in recreational settings. The Capabilities, Opportunities, and Motivations model of Behaviour (COM-B) informed the outline for 20 semi-structured telephone interviews (ever-performers, N = 8, age range = 20-45 years; never-performers, N = 12; age range = 20-50 years). Thematic analysis was used to identify barriers and enablers to earplug use, which were mapped onto the Theoretical Domains Framework (TDF). Six key domains of the TDF were identified. Ever-performers described being more exposed to 'social influences' (e.g., facilitators such as friends/peers) and were more positive than never-performers concerning 'beliefs about consequences' (e.g., earplug protection outweighs any negative effects on listening/communication). Involvement of 'emotion' (e.g., fear of losing ability to listen to music) and 'reinforcement' tactics (e.g., creating habits/routines) were discussed by ever-performers, but were not mentioned by never-performers. Both groups reported lack of 'environmental context and resources' (e.g., prompts and cues), and their own 'memory, attention, and decision processes' (e.g., deciding when to use earplugs) as barriers to earplug use. The present research identifies the variables that would need to change in order to increase earplug uptake and use in recreational settings among ever-performers and never-performers. Further work is required to translate these findings into testable interventions by selecting appropriate intervention functions (e.g., modelling), policy categories (e.g., communication/marketing), behaviour change techniques (e.g., demonstration of behaviour), and mode of delivery (e.g., face-to-face).


Subject(s)
Ear Protective Devices , Hearing Loss, Noise-Induced , Adult , Humans , Middle Aged , Motivation , Noise/adverse effects , Qualitative Research , Young Adult
5.
Hear Res ; 395: 108021, 2020 09 15.
Article in English | MEDLINE | ID: mdl-32631495

ABSTRACT

Musicians are at risk of hearing loss due to prolonged noise exposure, but they may also be at risk of early sub-clinical hearing damage, such as cochlear synaptopathy. In the current study, we investigated the effects of noise exposure on electrophysiological, behavioral and self-report correlates of hearing damage in young adult (age range = 18-27 years) musicians and non-musicians with normal audiometric thresholds. Early-career musicians (n = 76) and non-musicians (n = 47) completed a test battery including the Noise Exposure Structured Interview, pure-tone audiometry (PTA; 0.25-8 kHz), extended high-frequency (EHF; 12 and 16 kHz) thresholds, otoacoustic emissions (OAEs), auditory brainstem responses (ABRs), speech perception in noise (SPiN), and self-reported tinnitus, hyperacusis and hearing in noise difficulties. Total lifetime noise exposure was similar between musicians and non-musicians, the majority of which could be accounted for by recreational activities. Musicians showed significantly greater ABR wave I/V ratios than non-musicians and were also more likely to report experience of - and/or more severe - tinnitus, hyperacusis and hearing in noise difficulties, irrespective of noise exposure. A secondary analysis revealed that individuals with the highest levels of noise exposure had reduced outer hair cell function compared to individuals with the lowest levels of noise exposure, as measured by OAEs. OAE level was also related to PTA and EHF thresholds. High levels of noise exposure were also associated with a significant increase in ABR wave V latency, but only for males, and a higher prevalence and severity of hyperacusis. These findings suggest that there may be sub-clinical effects of noise exposure on various hearing metrics even at a relatively young age, but do not support a link between lifetime noise exposure and proxy measures of cochlear synaptopathy such as ABR wave amplitudes and SPiN. Closely monitoring OAEs, PTA and EHF thresholds when conventional PTA is within the clinically 'normal' range could provide a useful early metric of noise-induced hearing damage. This may be particularly relevant to early-career musicians as they progress through a period of intensive musical training, and thus interventions to protect hearing longevity may be vital.


Subject(s)
Hearing Loss, Noise-Induced , Music , Adolescent , Adult , Audiometry, Pure-Tone , Auditory Threshold , Evoked Potentials, Auditory, Brain Stem , Female , Hearing , Hearing Loss, Noise-Induced/diagnosis , Hearing Loss, Noise-Induced/etiology , Humans , Hyperacusis/diagnosis , Hyperacusis/etiology , Male , Otoacoustic Emissions, Spontaneous , Self Report , Tinnitus/diagnosis , Tinnitus/etiology , Young Adult
6.
Trends Hear ; 23: 2331216519885571, 2019.
Article in English | MEDLINE | ID: mdl-31747526

ABSTRACT

High levels of occupational noise exposure increase the risk of hearing difficulties and tinnitus. However, differences in demographic, health, and lifestyle factors could also contribute to high levels of hearing difficulties and tinnitus in some industries. Data from a subsample (n = 22,936) of the U.K. Biobank were analyzed to determine to what extent differences in levels of hearing difficulties and tinnitus in high-risk industries (construction, agricultural, and music) compared with low-risk industries (finance) could be attributable to demographic, health, and lifestyle factors, rather than occupational noise exposure. Hearing difficulties were identified using a digits-in-noise speech recognition test. Tinnitus was identified based on self-report. Logistic regression analyses showed that occupational noise exposure partially accounted for higher levels of hearing difficulties in the agricultural industry compared with finance, and occupational noise exposure, older age, low socioeconomic status, and non-White ethnic background partially accounted for higher levels of hearing difficulties in the construction industry. However, the factors assessed in the model did not fully account for the increased likelihood of hearing difficulties in high-risk industries, suggesting that there are additional unknown factors which impact on hearing or that there was insufficient measurement of factors included in the model. The levels of tinnitus were greatest for music and construction industries compared with finance, and these differences were accounted for by occupational and music noise exposure, as well as older age. These findings emphasize the need to promote hearing conservation in occupational and music settings, with a particular focus on high-risk demographic subgroups.


Subject(s)
Hearing Loss, Noise-Induced/epidemiology , Industry/statistics & numerical data , Life Style , Tinnitus/epidemiology , Adult , Aged , Demography , Female , Humans , Male , Middle Aged , Music , Noise/adverse effects , Occupational Exposure/statistics & numerical data , Risk Factors
7.
Trends Hear ; 23: 2331216519874165, 2019.
Article in English | MEDLINE | ID: mdl-31516095

ABSTRACT

The acoustic reflex (AR), a longstanding component of the audiological test battery, has received renewed attention in the context of noise-induced cochlear synaptopathy-the destruction of synapses between inner hair cells and auditory nerve fibers. Noninvasive proxy measures of synaptopathy are widely sought, and AR thresholds (ARTs) correlate closely with synaptic survival in rodents. However, measurement in humans at high stimulus frequencies-likely important when testing for noise-induced pathology-can be challenging; reflexes at 4 kHz are frequently absent or occur only at high stimulus levels, even in young people with clinically normal audiograms. This phenomenon may partly reflect differences across stimulus frequency in the temporal characteristics of the response; later onset of the response, earlier onset of adaptation, and higher rate of adaptation have been observed at 4 kHz than at 1 kHz. One temporal aspect of the response that has received little attention is the interstimulus interval (ISI); inadequate duration of ISI might lead to incomplete recovery of the response between successive presentations and consequent response fatigue. This research aimed to test for effects of ISI on ARTs in normally hearing young humans, measured at 1 and 4 kHz. Contrary to our hypotheses, increasing ISIs from 2.5 to 8.5 s did not reduce ART level, nor raise ART reliability. Results confirm that clinically measured ARTs-including those at 4 kHz-can exhibit excellent reliability and that relatively short (2.5 s) ISIs are adequate for the measurement of sensitive and reliable ARTs.


Subject(s)
Acoustic Stimulation , Auditory Threshold/physiology , Reflex, Acoustic/physiology , Adolescent , Cochlea , Evoked Potentials, Auditory, Brain Stem/physiology , Hearing , Hearing Tests , Humans , Noise , Reproducibility of Results , Synapses
8.
Trends Hear ; 23: 2331216519877301, 2019.
Article in English | MEDLINE | ID: mdl-31558119

ABSTRACT

Although there is strong histological evidence for age-related synaptopathy in humans, evidence for the existence of noise-induced cochlear synaptopathy in humans is inconclusive. Here, we sought to evaluate the relative contributions of age and noise exposure to cochlear synaptopathy using a series of electrophysiological and behavioral measures. We extended an existing cohort by including 33 adults in the age range 37 to 60, resulting in a total of 156 participants, with the additional older participants resulting in a weakening of the correlation between lifetime noise exposure and age. We used six independent regression models (corrected for multiple comparisons), in which age, lifetime noise exposure, and high-frequency audiometric thresholds were used to predict measures of synaptopathy, with a focus on differential measures. The models for auditory brainstem responses, envelope-following responses, interaural phase discrimination, and the co-ordinate response measure of speech perception were not statistically significant. However, both age and noise exposure were significant predictors of performance on the digit triplet test of speech perception in noise, with greater noise exposure (unexpectedly) predicting better performance in the 80 dB sound pressure level (SPL) condition and greater age predicting better performance in the 40 dB SPL condition. Amplitude modulation detection thresholds were also significantly predicted by age, with older listeners performing better than younger listeners at 80 dB SPL. Overall, the results are inconsistent with the predicted effects of synaptopathy.


Subject(s)
Cochlea/pathology , Hearing Loss, Noise-Induced/pathology , Acoustic Stimulation , Adult , Age Factors , Audiometry, Pure-Tone , Auditory Threshold/physiology , Evoked Potentials, Auditory, Brain Stem/physiology , Female , Humans , Male , Middle Aged , Noise , Speech Perception
9.
Multisens Res ; 32(8): 771-796, 2019 12 11.
Article in English | MEDLINE | ID: mdl-31291612

ABSTRACT

Multisensory integration typically follows the predictions of a statistically optimal model whereby the contribution of each sensory modality is weighted according to its reliability. Previous research has shown that multisensory integration is affected by ageing, however it is less certain whether older adults follow this statistically optimal model. Additionally, previous studies often present multisensory cues which are conflicting in size, shape or location, yet naturally occurring multisensory cues are usually non-conflicting. Therefore, the mechanisms of integration in older adults might differ depending on whether the multisensory cues are consistent or conflicting. In the current experiment, young ( n = 21) and older ( n = 30) adults were asked to make judgements regarding the height of wooden blocks using visual, haptic or combined visual-haptic information. Dual modality visual-haptic blocks could be presented as equal or conflicting in size. Young and older adults' size discrimination thresholds (i.e., precision) were not significantly different for visual, haptic or visual-haptic cues. In addition, both young and older adults' discrimination thresholds and points of subjective equality did not follow model predictions of optimal integration, for both conflicting and non-conflicting cues. Instead, there was considerable between subject variability as to how visual and haptic cues were processed when presented simultaneously. This finding has implications for the development of multisensory therapeutic aids and interventions to assist older adults with everyday activities, where these should be tailored to the needs of each individual.


Subject(s)
Aging/physiology , Cues , Size Perception/physiology , Touch Perception/physiology , Visual Perception/physiology , Adult , Aged , Female , Humans , Male , Middle Aged , Photic Stimulation , Physical Stimulation , Reproducibility of Results , Young Adult
10.
Health Informatics J ; 25(3): 1053-1064, 2019 09.
Article in English | MEDLINE | ID: mdl-29121820

ABSTRACT

Computer use is becoming ubiquitous among older adults. As computer use depends on complex cognitive functions, measuring individuals' computer-use behaviours over time may provide a way to detect changes in their cognitive functioning. However, it is uncertain which computer-use behaviour changes are most likely to be associated with declines of particular cognitive functions. To address this, we convened six experts from clinical and cognitive neurosciences to take part in two workshops and a follow-up survey to gain consensus on which computer-use behaviours would likely be the strongest indicators of cognitive decline. This resulted in a list of 21 computer-use behaviours that the majority of experts agreed would offer a 'strong indication' of decline in a specific cognitive function, across Memory, Executive function, Language and Perception and Action domains. This list enables a hypothesis-driven approach to analysing computer-use behaviours predicted to be markers of cognitive decline.


Subject(s)
Cognitive Dysfunction/diagnosis , User-Computer Interface , Aged , Aged, 80 and over , Education/methods , Executive Function , Female , Humans , Male , Neuropsychological Tests
11.
Trends Hear ; 22: 2331216518803213, 2018.
Article in English | MEDLINE | ID: mdl-30295145

ABSTRACT

Lifetime noise exposure is generally quantified by self-report. The accuracy of retrospective self-report is limited by respondent recall but is also bound to be influenced by reporting procedures. Such procedures are of variable quality in current measures of lifetime noise exposure, and off-the-shelf instruments are not readily available. The Noise Exposure Structured Interview (NESI) represents an attempt to draw together some of the stronger elements of existing procedures and to provide solutions to their outstanding limitations. Reporting is not restricted to prespecified exposure activities and instead encompasses all activities that the respondent has experienced as noisy (defined based on sound level estimated from vocal effort). Changing exposure habits over time are reported by dividing the lifespan into discrete periods in which exposure habits were approximately stable, with life milestones used to aid recall. Exposure duration, sound level, and use of hearing protection are reported for each life period separately. Simple-to-follow methods are provided for the estimation of free-field sound level, the sound level emitted by personal listening devices, and the attenuation provided by hearing protective equipment. An energy-based means of combining the resulting data is supplied, along with a primarily energy-based method for incorporating firearm-noise exposure. Finally, the NESI acknowledges the need of some users to tailor the procedures; this flexibility is afforded, and reasonable modifications are described. Competency needs of new users are addressed through detailed interview instructions (including troubleshooting tips) and a demonstration video. Limited evaluation data are available, and future efforts at evaluation are proposed.


Subject(s)
Hearing Loss, Noise-Induced/diagnosis , Hearing Loss, Noise-Induced/epidemiology , Noise, Occupational/adverse effects , Self Report , Cohort Studies , Female , Humans , Interviews as Topic , Male , Needs Assessment , Prognosis , Retrospective Studies , Risk Assessment , Severity of Illness Index , Time Factors
12.
Exp Brain Res ; 236(8): 2173-2184, 2018 08.
Article in English | MEDLINE | ID: mdl-29796755

ABSTRACT

Previous research suggests that the ability to adapt motor behaviour to sudden environmental changes may be impaired in older adults. Here, we investigated whether the adaptation of grasping behaviour in response to a visual-haptic size conflict is also affected by increasing age. 30 older and 18 young adults were instructed to grasp a hidden block whilst viewing a second block in a congruent position. Initially block sizes were equal, but after a set number of trials a sensory conflict was introduced by covertly changing the hidden block for a smaller or larger block. The scale and speed of maximum grasp aperture adaptation to the increase or decrease in the size of the hidden block was measured. Older adults successfully adapted to the visual-haptic size conflict in a similar manner to young adults, despite a tendency to adapt less when the hidden block increased in size. This finding is attributed to the physical capabilities of the grasping hand of older adults, rather than an effect of age-related sensory or cognitive decline. The speed of grasp adaptation did not differ between age groups; however, awareness of the visual-haptic conflict lead to faster adaptation. These findings suggest that sensorimotor adaptation for grasping is intact for cognitively healthy older adults.


Subject(s)
Adaptation, Physiological/physiology , Aging/physiology , Hand Strength/physiology , Size Perception/physiology , Touch/physiology , Vision, Ocular/physiology , Adult , Aged , Aged, 80 and over , Biomechanical Phenomena , Female , Humans , Male , Psychomotor Performance , Young Adult
13.
Hear Res ; 364: 38-47, 2018 07.
Article in English | MEDLINE | ID: mdl-29685616

ABSTRACT

The auditory brainstem response (ABR) is a sub-cortical evoked potential in which a series of well-defined waves occur in the first 10 ms after the onset of an auditory stimulus. Wave V of the ABR, particularly wave V latency, has been shown to be remarkably stable over time in individual listeners. However, little attention has been paid to the reliability of wave I, which reflects auditory nerve activity. This ABR component has attracted interest recently, as wave I amplitude has been identified as a possible non-invasive measure of noise-induced cochlear synaptopathy. The current study aimed to determine whether ABR wave I amplitude has sufficient test-retest reliability to detect impaired auditory nerve function in an otherwise normal-hearing listener. Thirty normal-hearing females were tested, divided equally into low- and high-noise exposure groups. The stimulus was an 80 dB nHL click. ABR recordings were made from the ipsilateral mastoid and from the ear canal (using a tiptrode). Although there was some variability between listeners, wave I amplitude had high test-retest reliability, with an intraclass correlation coefficient (ICC) comparable to that for wave V amplitude. There were slight gains in reliability for wave I amplitude when recording from the ear canal (ICC of 0.88) compared to the mastoid (ICC of 0.85). The summating potential (SP) and ratio of SP to wave I were also quantified and found to be much less reliable than measures of wave I and V amplitude. Finally, we found no significant differences in the amplitude of any wave components between low- and high-noise exposure groups. We conclude that, if the other sources of between-subject variability can be controlled, wave I amplitude is sufficiently reliable to accurately characterize individual differences in auditory nerve function.


Subject(s)
Auditory Threshold , Cochlear Nerve/physiopathology , Electroencephalography , Evoked Potentials, Auditory, Brain Stem , Noise/adverse effects , Acoustic Stimulation , Adult , Audiometry, Pure-Tone , Female , Humans , Otoacoustic Emissions, Spontaneous , Predictive Value of Tests , Reaction Time , Reproducibility of Results , Time Factors , Young Adult
14.
Multisens Res ; 31(3-4): 151-174, 2018 Jan 01.
Article in English | MEDLINE | ID: mdl-31264629

ABSTRACT

Older adults exhibit greater multisensory reaction time (RT) facilitation than young adults. Since older adults exhibit greater violation of the race model (i.e., cumulative distribution functions for multisensory RTs are greater than that of the summed unisensory RTs), this has been attributed to enhanced multisensory integration. Here we explored whether (a) individual differences in RT distributions within each age group might drive this effect, and (b) the race model is more likely to be violated if unisensory RTs are slower. Young (n=34) and older adults (n=30) made speeded responses to visual, auditory or tactile stimuli, or any combination of these (bi-/tri-modal). The test of the race model suggested greater audiovisual integration for older adults, but only when accounting for individual differences in RT distributions. Moreover, correlations in both age groups showed that slower unisensory RTs were associated with a greater degree of race model violation. Therefore, greater race model violation may be due to greater 'room for improvement' from unisensory responses in older adults compared to young adults, and thus could falsely give the impression of enhanced multisensory integration.

15.
Multisens Res ; 30(6): 509-536, 2017 Jan 01.
Article in English | MEDLINE | ID: mdl-31287089

ABSTRACT

A number of studies have shown that multisensory performance is well predicted by a statistically optimal maximum likelihood estimation (MLE) model. Under this model unisensory estimates are combined additively and weighted according to relative reliability. Recent theories have proposed that atypical sensation and perception commonly reported in autism spectrum condition (ASC) may result from differences in the use of reliability information. Furthermore, experimental studies have indicated that multisensory processing is less effective in those with the condition in comparison to neurotypical (NT) controls. In the present study, adults with ASC (n=13) and a matched NT group (n=13) completed a visual-haptic size judgement task (cf. Gori et al., 2008) in which participants compared the height of wooden blocks using either vision or haptics, and in a dual modality condition in which visual-haptic stimuli were presented in size conflict. Participants with ASC tended to produce more reliable estimates than the NT group. However, dual modality performance was not well predicted by the MLE model for either group. Performance was subsequently compared to alternative models in which the participant either switched between modalities trial to trial (rather than integrating) and a model of non-optimal integration. Performance of both groups was statistically comparable to the cue-switching model. These findings suggest that adults with ASC adopted a similar strategy to NTs when processing conflicting visual-haptic information. Findings are discussed in relation to multisensory perception in ASC and methodological considerations associated with multisensory conflict paradigms.

16.
Exp Brain Res ; 234(5): 1233-48, 2016 May.
Article in English | MEDLINE | ID: mdl-26449968

ABSTRACT

Previous research has shown that spatially and temporally disparate multisensory events are more likely to interact for older adults. For visuotactile interactions, this suggests that the representation of peripersonal space is expanded and temporal perception within this space is less precise. Previously, visuotactile space has been found to expand horizontally into the opposite hemispace, and here we sought to replicate and extend this by exploring both horizontal and vertical space from the hand. Moreover, we investigated whether both spatial and temporal domains are affected for an individual, which have previously been measured using distinct tasks and different participants. We presented a modified cross-modal congruency task (Poole et al. in Multisens Res. doi: 10.1163/22134808-00002475 , 2015a) to thirty older participants (age range 65-85 years), with unisensory tactile performance equated for each individual. For the temporal manipulation, the timings of visual distractors and tactile targets were offset. For the spatial manipulation, visual distractors were presented from multiple positions in ipsilateral and contralateral hemispaces. Whilst the temporal modulation of visuotactile interactions for older adults was equivalent to that observed in young adults, spatial modulation was reduced; significant visuotactile interactions were observed for visual distractors presented in the same and opposite hemispace to the stimulated hand, in the lower visual field. This suggests an expanded representation of visuotactile space surrounding the hand in older adults, which occurs horizontally into the contralateral hemispace only, rather than expanding both vertically and horizontally. This is likely to have consequences for perception of space and goal-directed action in ageing.


Subject(s)
Attention/physiology , Geriatric Assessment , Space Perception/physiology , Time Perception/physiology , Touch/physiology , Visual Perception/physiology , Aged , Aged, 80 and over , Female , Functional Laterality , Humans , Inhibition, Psychological , Male , Neuropsychological Tests , Photic Stimulation , Statistics as Topic
17.
Multisens Res ; 28(3-4): 227-44, 2015.
Article in English | MEDLINE | ID: mdl-26288897

ABSTRACT

The crossmodal congruency task (CCT) is a commonly used paradigm for measuring visual-tactile interactions and how these may be influenced by discrepancies in space and time between the tactile target and visual distractors. The majority of studies which have used this paradigm have neither measured, nor attempted to control, individual variability in unisensory (tactile) performance. We have developed a version of the CCT in which unisensory baseline performance is constrained to enable comparisons within and between participant groups. Participants were instructed to discriminate between single and double tactile pulses presented to their dominant hand, at their own approximate threshold level. In Experiment 1, visual distractors were presented at -30 ms, 100 ms, 200 ms and 400 ms stimulus onset asynchronies. In Experiment 2, ipsilateral visual distractors were presented 0 cm, 21 cm, and 42 cm vertically from the target hand, and 42 cm in a symmetrical, contralateral position. Distractors presented -30 ms and 0 cm from the target produced a significantly larger congruency effect than at other time points and spatial locations. Thus, the typical limits of visual-tactile interactions were replicated using a version of the task in which baseline performance can be constrained. The usefulness of this approach is supported by the observation that tactile thresholds correlated with self-reported autistic traits in this non-clinical sample. We discuss the suitability of this adapted version of the CCT for measuring visual-tactile interactions in populations where unisensory tactile ability may differ within and between groups.


Subject(s)
Psychomotor Performance , Space Perception/physiology , Touch Perception/physiology , Visual Perception/physiology , Adult , Female , Humans , Male , Photic Stimulation/methods , Reaction Time , Young Adult
18.
Exp Brain Res ; 232(3): 855-64, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24337351

ABSTRACT

Previous research has demonstrated faster reaction times in response to appropriately oriented action-inducing stimuli (affordance effect, e.g. Tucker and Ellis in J Exp Psychol Hum Percept Perform 24:830-846, 1998). However, it has been argued that faster responses may be due to a spatial compatibility effect. In the current investigation, we aimed to dissociate the affordance and spatial compatibility effects. Moreover, we explored these effects beyond button-press responses by measuring detailed kinematics of the arms and hands during a naturalistic reach response. Participants were presented with images of a door handle (affording) or an abstract (non-affording) stimulus and made a pantomimed reach response with either hand depending on a colour change of the stimulus (i.e. Blue = left, Green = right). Stimuli could be aligned as spatially compatible or incompatible with the responding hand. The colour change occurred after a delay of 0, 500 or 1,000 ms. Only spatially compatible affordance stimuli facilitated reach onset compared to other stimuli and compatibility combinations, replicating previous reaction time studies. Therefore, in the absence of graspable stimuli, spatial compatibility alone was not sufficient to facilitate reach onset. There was also a larger outwards deviation of reach trajectory for spatially incompatible abstract stimuli compared to spatially compatible abstract stimuli, which waned with stimulus onset delay. However, no such affect was observed for the affording stimuli. Accordingly, later kinematics of the reaching action was influenced by the spatial compatibility of the stimulus alone. Overall, the dissociation of affordance and spatial compatibility effects suggests that these effects are driven by visuomotor priming and the inhibition of the incompatible spatial location, respectively.


Subject(s)
Orientation/physiology , Psychomotor Performance/physiology , Reaction Time/physiology , Space Perception/physiology , Adolescent , Adult , Biomechanical Phenomena , Female , Functional Laterality , Hand Strength , Humans , Male , Photic Stimulation , Young Adult
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