In an era of bilateral funding and changing criteria, when is unilateral cochlear implantation a better option?

BACKGROUND: Funding for paediatric bilateral cochlear implantation became available in Ireland in 2014. Prior to this, children eligible for cochlear implantation received a unilateral implant. OBJECTIVE: To examine the cohort of children who received a unilateral cochlear implant in the 4 year period following bilateral cochlear implantation funding becoming available. METHODS: A clinical audit of all children implanted for the first time between July 2014 and July 2018. The unilaterally implanted children (n = 105) were divided into 3 groups according to whether they met the audiometric thresholds for implantation in neither ear (Group 1), one ear (Group 2) or both ears (Group 3). One year post operative functional outcomes were examined for all 3 groups. RESULTS: All 3 groups showed significant improvements in functional outcomes at 1 year post op. To date, 20% of the unilaterally implanted children have proceeded to get a sequential CI, often where there was no change in audiological status. CONCLUSIONS: The number of children in Groups 1 and 2 highlighted how our decision making around cochlear implantation has changed in recent years. Unilateral cochlear implantation in certain circumstances is good practice, independent of the audiological profile when an experienced multi-disciplinary team (MDT) is involved in the decision making process. Decision making using a holistic model approach is key, including involving the parent/carer and, where appropriate, the child/teenager themselves. A staged bilateral cochlear implant is also a good option, where careful monitoring and support for the first implant has resulted in positive outcomes.

National study of hearing preservation rates and outcomes after cochlear implantation in Ireland.

OBJECTIVE: To study the rate of hearing preservation and outcomes of hearing preservation candidates in a national cochlear implant centre. The HEARRING criteria was used. METHODS: All cochlear implant candidates with preserved low frequency pure tone average (PTA) were included. All patients underwent cochlear implantation using a standard 'soft-surgery' technique. PTA was assessed at switch-on, 3, 6, 9 and 12 months postoperatively. The primary outcome was hearing preservation at 12 months. RESULTS: Sixty six patients were included in the study between 2015 and 2020. Seventy one ears were implanted including 33 adults and 33 children with 5 bilateral implantations. Mean preoperative PTA was 74.8 dB (range 52.3-92 dB), mean postoperative PTA was 95.3 dB corresponding to a mean shift of 20.5 dB. In the adult population, HP rates were as follows: complete HP in 13%, partial HP in 39.1%, minimal HP in 30.4%, loss of hearing in 17.4%. In the paediatric population: complete HP in 20.7%, partial HP in 51.7%, minimal HP in 13.8% and loss of hearing in 13.8%. After the initial postoperative shift, there was no significant worsening of residual hearing during follow-up between 3 and 12 months. There were no significant prognostic factors for hearing preservation. CONCLUSION: Hearing preservation rates using the HEARRING criteria are described. This study will help counselling and decision making in patients eligible for cochlear implantation with hearing preservation. Further studies are required to assess the performances and outcomes of electronatural and electroacoustic stimulation.

New approach in programming sequentially implanted children: Towards balanced dynamic ranges (DR).

There is a tendency for children undergoing sequential cochlear implant after a long period of unilateral implant use to have a smaller dynamic range in their second implant compared to their first implant. This study aimed to investigate if balancing the dynamic ranges between the two implants influenced functional outcomes in sequentially implanted children. Nineteen participants with long inter-implant time delays were randomly assigned to a study group or a control group. Children in the study group received progressive minimal changes to both first and second implants over a period of nine months to achieve balanced dynamic ranges, while the children in the control group received only changes to their sequential implant. Functional outcomes were collected 24-months after sequential implantation and consisted of speech discrimination scores, spatial localisation, device use and quality of life measures. Results show that spatial discrimination skills improved over time for both groups of children; however children in the study group had smaller localisation errors compared with the children in the control group. No other differences between the two groups were observed. Balanced dynamic ranges in sequentially implanted children can contribute to better performance, particularly in spatial discrimination tasks that rely in inter-aural level differences.

Listening and spoken language outcomes after 5 years of cochlear implant use for children born preterm and at term.

AIM: To compare listening and spoken language outcomes after cochlear implantation for children born preterm and at term, and to examine patterns associated with additional disabilities or gestational age. METHOD: Children were included if they underwent cochlear implantation in 2013 or 2014 and had complete 5-year follow-up data available. An analysis of assessment data recorded annually was conducted, including outcomes as measured by the Category of Auditory Performance (CAP), the Speech Intelligibility Rating, Second Edition (SIR 2) scale, and the British Picture Vocabulary Scales, Third Edition (BPVS-3). Analyses were conducted to measure the impact of preterm birth and of additional causes of disability on these outcomes. RESULTS: Eighty-two children (39 males, 43 females; median corrected age at first cochlear implantation 28.5mo [interquartile range 16.3-48.5]) were included in the study. Children who underwent cochlear implantation experienced significant improvements as measured by the CAP, SIR 2, and BPVS-3. Comparable improvements were seen in the groups born at term and preterm. Children with additional disabilities experienced significant improvement in all measures but performed less well than children without additional disabilities. INTERPRETATION: Infants born preterm benefit from cochlear implantation to a degree comparable to their peers born at term. Additional disabilities may limit improvements in speech intelligibility, listening performance, and receptive vocabulary. Children with additional disabilities, nonetheless, derived significant benefit from cochlear implantation; additional benefits of cochlear implantation for this subgroup may go unmeasured by the outcome tools used in this study.

A retrospective review of parents' perceptions of the impact of bilateral cochlear implants on their child's quality of life.

OBJECTIVE: To evaluate the impact of simultaneous and sequential bilateral cochlear implantation on deaf children's quality of life (QoL) and to investigate the impact of inter-implant time delay for the sequentially implanted children. METHODS: All completed questionnaires of the Brief Assessment of Parental Perception (BAPP), which had been routinely filled out by parents at annual review, were analysed for children with at least 12 months of bilateral implant experience. The responses for the simultaneous implanted group were compared to those who received sequential implants. Within the sequential group, the impact of shorter (<7 years) and longer (>7 years) inter-implant delays on QoL were compared. RESULTS: There were a total of 176 children in the sequential group and 97 in the simultaneous group. Results indicated that most children wore their devices regularly and significant improvements in QoL were reported for all children particularly in communication and learning. QoL scores were higher for the children with simultaneous implants, followed by children with a shorter time delay between implants. CONCLUSION: Both simultaneous and sequential bilateral cochlear implants significantly improved the functioning and QoL of deaf children.

Sequential bilateral implantation in older children: Inter-implant map differences and their effects on functional outcomes.

OBJECTIVES: It is well established that sequential bilateral implantation offers functional benefits in speech in noise and sound localisation, although it can be challenging to get long-term unilateral users to adapt to the second implant. The aim of this study was to investigate programming differences between the two cochlear implants that can impact on performance outcomes. DESIGN: Cohort Study. PARTICIPANTS: Sixteen older children who received sequential implants in Ireland and with at least one-year experience with their sequential implant were included in this study. Children were categorised into two groups according to the time interval between the two implants: short if the time between the two implants was less than eight years and long if more than eight years. MAIN OUTCOME MEASURES: Dynamic ranges and current levels were compared for both implants. Functional outcome measures included sentence discrimination in quiet and in noise and sound localisation. RESULTS: Results show that for the children with long inter-implant delays, the dynamic range of their second implant was on average 34% less than the dynamic range of their first implant. This difference was driven by smaller comfort levels in the second implant compared to the first. Children with longer inter-implant delays also show lower speech discrimination scores with their second implant compared to children with shorter delays, in addition to no bilateral advantage in speech in noise, that is their performance in unilateral mode does not differ from the performance in bilateral mode. Finally, children with longer delays demonstrate poor performance in sound localisation compared to the children with shorter delays. CONCLUSION: Sequentially implanted older children show limited functional benefits from the second implant. The observed functional benefits are determined both by a short inter-implant delay and by having balanced dynamic ranges between the two implants.

Impact of Universal Newborn Hearing Screening on cochlear implanted children in Ireland.

OBJECTIVES: Cochlear Implant (CI) is an established treatment for severe to profound hearing loss (HL). Early diagnosis and intervention in HL are crucial in order to provide access to sound and increase the likelihood of spoken language development in pre-lingually deaf children. In April 2011, the Health Service Executive (HSE) implemented the Universal Newborn Hearing Screening (UNHS) in a phased regional basis in Ireland. This study aimed to investigate the general clinical pathway for UNHS referrals to the CI service and to evaluate the impact of earlier referrals via UNHS on functional outcomes in children. METHODS: The first part of this study constituted a retrospective review of 100 children referred to the National Hearing Implant and Research Centre (NHIRC) via UNHS from November 2011 to December 2016. Implanted children referred via UNHS were categorised into three groups according to their medical status. Their clinical pathway to cochlear implantation was evaluated. Functional outcomes were investigated based on medical and developmental status, respectively. In the second part of this study, developmentally healthy implanted children referred post-UNHS were compared with medically healthy children referred pre-UNHS under the age of four, from January 2005 to June 2011. Current implant status of children, age at referral and functional outcomes were investigated. RESULTS: Medically healthy children were referred to the NHIRC at an earlier age than the medically complex children (2.8 months vs 5.2 months, p < 0.01) and the children presenting with auditory neuropathy spectrum disorder (ANSD) (2.8 months vs 5.3 months, p < 0.01). On average they attended their first appointment and were implanted at a younger age than the ANSD group (6.1 months vs 10.1 months, p < 0.01; 16.3 months vs 29.4 months, p < 0.001, respectively). Developmentally healthy children had significantly better functional outcomes than children with developmental delays. Children referred via UNHS were referred and implanted at a younger age than those referred pre-UNHS. The former group achieved better Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores 2 years post-implantation. CONCLUSION: UNHS in Ireland is an important platform for earlier diagnosis and management of congenital HL and our results show that early intervention has a positive impact on functional outcomes in children.

Balance, gait and dizziness in adult cochlear implant users: A cross sectional study.

Objective: Cochlear implantation is associated with vestibular impairment due to the close proximity of the structures. The aim of the study was to quantify dizziness/vertigo, gaze instability, balance and gait problems in a sample of adult cochlear implant (CI) users.Methods: An observational, cross sectional study evaluated subjective dizziness (Vestibular Rehabilitation Benefit Questionnaire (VRBQ)), balance confidence (Activities Specific Balance Questionnaire (ABC)), gait (Functional Gait Assessment (FGA) and 10m walk test), balance (Equitest Sensory Organisation Test (SOT)), and computerised dynamic visual acuity (DVA). The Dix Hallpike test was performed to test for benign paroxysmal positional vertigo (BPPV).Results: Twenty participants (n=10F), 2.8(±2.7) years post implantation, with mean age 59.3(±15.8) years were assessed. Subjective dizziness (VRBQ) was low (15.0% (±15.5)) and balance confidence was high (ABC: 82.1%±14.9). FGA scores (25.1 ± 4.4) and gait speed (1.8 (±0.3) m/sec) were below normal. Dx Hallpike was positive in 3. Gaze instability was found in 50% (DVA loss, 0.29 (± 0.16) LogMAR), while 79% demonstrated balance impairment (mean SOT score, 57.8%±14.5), with 42% falling on SOT condition 5.Discussion: Evidence of vestibular dysfunction was identified in these adult CI users.Conclusion: Access to vestibular function assessment and rehabilitation is required in adult CI users.

The impact of repetitive hyperbaric exposure during SCUBA diving on cochlear implants.

OBJECTIVES/HYPOTHESIS: Complications during or after cochlear implantation are relatively rare. They occur more frequently in patients who partake in activities that can potentially lead to local trauma. No formal recommendations exist for participation in self-contained underwater breathing apparatus (SCUBA) activities. We describe three patients with a combined five cochlear implants and extensive diving experience, the largest case series to date, and highlight some of the difficulties faced. We also review the literature on previously described SCUBA-diving patients with cochlear implants. STUDY DESIGN: Retrospective case series and literature review. METHODS: A review of the known SCUBA divers in the National Hearing Implant and Research Centre in Ireland was conducted, and a review of the literature was carried out using PubMed and Google Scholar. RESULTS: Of the three SCUBA divers with cochlear implants, two required reimplantation, the first due to nonauditory stimulation, and the second due to extrusion of the electrode through the tympanic membrane following repetitive SCUBA dives. The third patient remains without complications after 80 dives. CONCLUSIONS: Patients with cochlear implants can have complications relating to the implant itself, with device failure a theoretical risk. The cochleostomy can lead to perilymphatic extravasation, as well as inner ear barotrauma, decompression sickness, and formation of air bubbles along the electrode. A combination of deafness, vestibulopathy with abrupt perilymph leak, and loss of proprioception can lead to disorientation and blue dome syndrome. Based on our experience with cochlear implants in SCUBA divers, along with those reported in the literature, we recommend caution in patients with cochlear implants who SCUBA dive regularly and strict adherence to the recommended safety limits. LEVEL OF EVIDENCE: 4 129:2760-2764, 2019.

Occurrence of major complications after cochlear implant surgery in Ireland.

OBJECTIVES: Cochlear implantation (CI) is considered an effective and relatively safe procedure for patients with severe-profound hearing loss. However, severe complications are reported in several studies. The purpose of this study was to report the frequency and management of major complications following CI surgery at the National CI Programme (NCIP) in Ireland. METHODS: Major complications were defined according to the classification of Hansen et al. 2010. The medical records of 1017 patients undergoing CI between 1995 and 2016 were analyzed retrospectively for major complications. In addition, radiological and intraoperative findings as well as therapeutic management of all patients with a major complication were reviewed. RESULTS: Altogether, 1017 patients underwent 1266 CI surgeries. The median follow-up of all CI surgeries was 44 months. The total number of major complications identified was 21 which corresponds to an overall rate of 1.7%. The majority of major complication (71%) occurred at least one week after surgery. The most common major complications were internal receiver/stimulator protrusion and migration (6/21), followed by migration of the electrode array (4/21) and recurrent otitis media requiring re-implantation (4/21). All patients with major complications required additional surgery, with reimplantation necessary in 19 patients (90%). DISCUSSION: CI surgery is a safe surgical procedure for hearing rehabilitation associated with a low rate of severe complications. However, major complications can occur many years after surgery, making revision surgery necessary. CONCLUSION: Long-term follow-up is necessary for the early identification of complications to facilitate appropriate care.

Tactile-to-Visual Cross-Modal Transfer of Texture Categorisation Following Training: An fMRI Study.

We investigated the neural underpinnings of texture categorisation using exemplars that were previously learned either within modalities (visual training and visual test) or across modalities (tactile training and visual test). Previous models of learning suggest a decrease in activation in brain regions that are typically involved in cognitive control during task acquisition, but a concomitant increase in activation in brain regions associated with the representation of the acquired information. In our study, participants were required to learn to categorise fabrics of different textures as either natural or synthetic. Training occurred over several sessions, with each fabric presented either visually or through touch to a participant. Pre- and post-training tests, in which participants categorised visual images only of the fabrics, were conducted during a functional magnetic resonance imaging (fMRI) scan. Consistent with previous research on cognitive processes involved in task acquisition, we found that categorisation training was associated with a decrease in activation in brain regions associated with cognitive systems involved in learning, including the superior parietal cortex, dorsal anterior cingulate cortex (dACC), and the right dorsolateral prefrontal cortex (DLFC). Moreover, these decreases were independent of training modality. In contrast, we found greater activation to visual textures in a region within the left medial occipital cortex (MOC) following training. There was no overall evidence of an effect of training modality in the main analyses, with texture-specific regional changes associated with both within- (visual) and cross- (touch) modal training. However, further analyses suggested that, unlike categorisation performance following within-modal training, crossmodal training was associated with bilateral activation of the MOC. Our results support previous evidence for a multisensory representation of texture within early visual regions of the cortex and provide insight into how multisensory categories are formed in the brain.

Quality of life outcomes in cochlear implantation of children with profound and multiple learning disability.

This study was performed to investigate the effect of cochlear implantation on the Quality of Life (QoL) of children with profound and multiple learning disability (PMLD). This cohort of children has been viewed historically as poor candidates for cochlear implantation as they generally have poor speech and hearing outcomes. The Irish National Cochlear Implant Program's prospectively maintained database was examined for all children implanted from July 1996 to July 2015. All charts of the 381 children implanted during this time were reviewed retrospectively; 16 children met criteria for being PMLD. For this cohort of patients, speech and hearing performance and the Glasgow Children's Benefit Inventory scores were retrospectively analyzed. Speech and hearing outcomes, as measured by Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores, demonstrated little or no improvement from pre-implantation to an interval 3 years post-op; however, 11 out of 16 parents reported an improvement in their child's quality of life after implantation with 3 out of 16 reporting no improvement. This study suggests that despite children with PMLD performing poorly on traditional outcome measures such as CAP and SIR they may have improvement to their QoL after cochlear implantation. Further study is warranted to characterize the impact of CI on these children.

Depth matters - Towards finding an objective neurophysiological measure of behavioral amplitude modulation detection based on neural threshold determination.

With increasing numbers undergoing intervention for hearing impairment at a young age, the clinical need for objective assessment tools of auditory discrimination abilities is growing. Amplitude modulation (AM) sensitivity has been known to be an important factor for speech recognition particularly among cochlear implant (CI) users. It therefore would be useful to develop objective measures of AM detection for future clinical assessment of CI users; this study aimed to verify the feasibility of a neurophysiological approach studying a cohort of normal-hearing participants. The mismatch waveform (MMW) was evaluated as a potential objective measure of AM detection for a low modulation rate (8 Hz). This study also explored the relationship between behavioral AM detection and speech-in-noise recognition. The following measures were obtained for 15 young adults with no known hearing impairment: (1) psychoacoustic sinusoidal AM detection ability for a modulation rate of 8 Hz; (2) neural AM detection thresholds estimated from morphology weighted cortical auditory evoked potentials elicited to various AM depths; and (3) AzBio sentence scores for speech-in-noise recognition. No significant correlations were found between speech recognition and behavioral AM detection measures. Individual neural thresholds were obtained from MMW data and showed significant positive correlations with behavioral AM detection thresholds. Neural thresholds estimated from morphology weighted MMWs provide a novel, objective approach for assessing low-rate AM detection. The findings of this study encourage the continued investigation of the MMW as a neural correlate of low-rate AM detection in larger normal-hearing cohorts and subsequently in clinical cohorts such as cochlear implant users.

Stimulus-rate sensitivity discerns area 3b of the human primary somatosensory cortex.

Previous studies have shown that the hemodynamic response of the primary somatosensory cortex (SI) to electrical median nerve stimulation doubles in strength when the stimulus rate (SR) increases from 1 to 5 Hz. Here we investigated whether such sensitivity to SR is homogenous within the functionally different subareas of the SI cortex, and whether SR sensitivity would help discern area 3b among the other SI subareas. We acquired 3-tesla functional magnetic resonance imaging (fMRI) data from nine healthy adults who received pneumotactile stimuli in 25-s blocks to three right-hand fingers, either at 1, 4, or 10 Hz. The main contrast (all stimulations pooled vs. baseline), applied to the whole brain, first limited the search to the whole SI cortex. The conjunction of SR-sensitive contrasts [4 Hz - 1 Hz] > 0 and [10 Hz - 1 Hz] > 0 ([4 Hz - 1 Hz] + [10 Hz - 1 Hz] > 0), applied to the SI cluster, then revealed an anterior-ventral subcluster that reacted more strongly to both 10-Hz and 4-Hz stimuli than to the 1-Hz stimuli. No other SR-sensitive clusters were found at the group-level in the whole-brain analysis. The site of the SR-sensitive SI subcluster corresponds to the canonical position of area 3b; such differentiation was also possible at the individual level in 5 out of 9 subjects. Thus the SR sensitivity of the BOLD response appears to discern area 3b among other subareas of the human SI cortex.

Active and passive touch differentially activate somatosensory cortex in texture perception.

The neural mechanisms behind active and passive touch are not yet fully understood. Using fMRI we investigated the brain correlates of these exploratory procedures using a roughness categorization task. Participants either actively explored a surface (active touch) or the surface was moved under the participant's stationary finger (passive touch). The stimuli consisted of three different grades of sandpaper which participants were required to categorize as either coarse, medium, or fine. Exploratory procedure did not affect performance although the coarse and fine surfaces were more easily categorized than the medium surface. An initial whole brain analysis revealed activation of sensory and cognitive areas, including post-central gyrus and prefrontal cortical areas, in line with areas reported in previous studies. Our main analysis revealed greater activation during active than passive touch in the contralateral primary somatosensory region but no effect of stimulus roughness. In contrast, activation in the parietal operculum (OP) was significantly affected by stimulus roughness but not by exploration procedure. Active touch also elicited greater and more distributed brain activity compared with passive touch in areas outside the somatosensory region, possibly due to the motor component of the task. Our results reveal that different cortical areas may be involved in the processing of surface exploration and surface texture, with exploration procedures affecting activations in the primary somatosensory cortex and stimulus properties affecting relatively higher cortical areas within the somatosensory system.

Executive function and error detection: The effect of motivation on cingulate and ventral striatum activity.

Reacting appropriately to errors during task performance is fundamental to successful negotiation of our environment. This is especially true when errors will result in a significant penalty for the person performing a given task, be they financial or otherwise. Error responses and monitoring states were manipulated in a GO/NOGO task by introducing a financial punishment for errors. This study employed a mixed block design alternating between punishment and no punishment (neutral) conditions, enabling an assessment of tonic changes associated with cognitive control as well as trial-specific effects. Behavioural results revealed slower responses and fewer commission errors in the punishment condition. The dorsal anterior cingulate cortex (ACC) had equal trial-specific activity for errors in the neutral and punishment conditions but had greater tonic activity throughout the punishment condition. A region of interest analysis revealed different activation patterns between the dorsal and the rostral parts of the ACC with the rostral ACC having only trial-specific activity for errors in the punishment condition, an activity profile similar to one observed in the nucleus accumbens. This study suggests that there is a motivational influence on cognitive processes in the ACC and nucleus accumbens and hints at a dissociation between tonic proactive activity and phasic reactive error-related activity.

Static images of novel, moveable objects learned through touch activate visual area hMT+.

Although many studies have found similar cortical areas activated during the recognition of objects encoded through vision or touch, little is known about cortical areas involved in the crossmodal recognition of dynamic objects. Here, we investigated which cortical areas are involved in the recognition of moving objects and were specifically interested in whether motion areas are involved in the recognition of dynamic objects within and across sensory modalities. Prior to scanning, participants first learned to recognise a set of 12 novel objects, each presented either visually or haptically, and either moving or stationary. We then conducted fMRI whilst participants performed an old-new task with static images of learned or not-learned objects. We found the fusiform and right inferior frontal gyri more activated to within-modal visual than crossmodal object recognition. Our results also revealed increased activation in area hMT+, LOC and the middle occipital gyrus, in the right hemisphere only, for the objects learned as moving compared to the learned static objects, regardless of modality. We propose that the network of cortical areas involved in the recognition of dynamic objects is largely independent of modality and have important implications for understanding the neural substrates of multisensory dynamic object recognition.

The role of the dorsal anterior cingulate in evaluating behavior for achieving gains and avoiding losses.

Effective goal-directed behavior relies on a network of regions including anterior cingulate cortex and ventral striatum to learn from negative outcomes in order to improve performance. We employed fMRI to determine if this frontal-striatal system is also involved in instances of behavior that do not presume negative circumstances. Participants performed a visual target/nontarget search game in which they could optionally abort a trial to avoid errors or receive extra reward for highly confident responses. Anterior cingulate and prefrontal cortex were equally activated for error avoidance and high reward trials but were not active on error trials, demonstrating their primary involvement in self-initiated behavioral adjustment and not error detection or prediction. In contrast, the insula and the ventral striatum were responsive to the high reward trials. Differential activation patterns across conditions for the nucleus accumbens, insula, and prefrontal cortex suggest distinct roles for these structures in the control of reward-related behavior.

Menstrual cycle phase modulates cognitive control over male but not female stimuli.

Evolutionary selection pressures have been one of the factors proposed to underlie sex differences in inhibitory control. Consequently, inhibitory control may vary as a function of the menstrual cycle and may be modulated by the stimuli being processed if these stimuli are related to reproductive success. We used functional MRI to study women's brain activation across the menstrual cycle on a GO/NOGO response inhibition task using attractive male and female faces as stimuli. We detected brain activity changes for both successful inhibitions and errors of commission that were unique to the male stimuli during the follicular phase of the menstrual cycle. That is, when pregnancy was possible women had superior inhibitory brain function and heightened detection of inhibitory failures when processing male stimuli. Moreover, we show that individual differences between females in sexual desire and social risk taking negatively correlate with error-related brain activity to the male stimuli during the follicular phase of the menstrual cycle. These results suggest an interaction between hormonal influences and stimulus-specific effects in producing an endophenotypic outcome predicted by evolutionary psychology, and suggest that the functioning of the brain's monitoring system can predict individual differences in both traits and real-world risk-taking behaviours.

Vision and touch: independent or integrated systems for the perception of texture?

In the following review, we discuss the evidence for the role of vision and touch in the perception of texture with the particular aim of evaluating whether these systems contribute information to texture perception in either an independent or integrated manner. Although texture is perceived by both vision and touch, several behavioural and neuroimaging studies have suggested that texture information is processed in qualitatively different ways, such that the type of information encoded and the manner in which it is encoded differs across these sensory systems. Furthermore, vision and touch perceive different aspects of texture information with vision the more appropriate modality for discriminating texture boundaries and touch the more appropriate modality for discriminating stimulus roughness and compliance. Differences also exist in the neural structures and functions which underlie these systems, further suggesting independence of these modalities in the perception of texture. Accordingly, recent evidence suggests that behavioural tasks involving texture perception do not benefit from integration across the senses, suggesting that qualitatively different information is represented across vision and touch which cannot be combined to enhance perceptual performance. Research using more familiar objects, however, does suggest a role for sensory integration on texture perception, although these effects may be due to more cognitive influences rather than basic sensory encoding. In sum, we suggest that unlike shape perception, vision and touch contribute information to the perception of texture in an independent but complementary manner.