Authors:

HENDERSON, S., HALAI, A., Tsvetanov, K.A., Cope, T.E., PATTERSON, K.E., ROWE, J.B., LAMBON RALPH, M.

Reference:

Year of publication:

2025

CBU number:

9189

Abstract:

Background Impaired phonological short-term memory is a core feature of the logopenic variant of primary progressive aphasia (lvPPA), but it is not clear whether a core phonological processing deficit is also present. Methods We asked three questions: (i) beyond short-term memory impairment, do lvPPA patients have an impairment within phonology itself?; (ii) is their performance in working memory and naming reflective of this phonological impairment?; and (iii) is their repetition performance related to structural and functional differences in key language-dominant regions? We compared non-word and word repetition and short-term memory performance in patients with typical Alzheimer's disease (tAD), lvPPA per consensus criteria, and others who previously satisfied definitions of lvPPA but had progressed with multi-domain cognitive impairments (lvPPA+). Results Bayesian analyses revealed no group differences in phonological tasks of word and non-word repetition. We found very strong evidence for an effect of self-reported hearing loss on word and non-word repetition, but not multi-syllabic word/phrase repetition. A comparison of phonological versus working memory and naming tasks produced either no evidence or evidence for no correlation. Beyond the expected grey matter reductions in patients relative to controls, there was anecdotal evidence for an association between non-word repetition and functional connectivity between dorsal premotor and posterior superior temporal gyrus regions in patients. Conclusions Our results indicated that, in the absence of self-reported hearing loss, patients did not exhibit impairments in tasks tapping "pure" phonological processing. Our results suggest that instead of having a core phonological impairment, lvPPA patients have a working memory/buffering impairment.

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Authors:

MEHRHOD, S., FLEMING, H., NORD, C.

Reference:

Year of publication:

2025

CBU number:

9188

Abstract:

Mental health conditions like depression are associated with an elevated risk of cardiometabolic disorders, yet the mechanisms underlying this comorbidity remain poorly understood. Is metabolic dysfunction a cause of depression, a downstream consequence, or do both stem from shared underlying processes? We argue that neurocognitive mechanisms, particularly those involved in reward and effort processing, interact with metabolic physiology to shape each of these causal pathways. Metabolic signals do not act on the brain in isolation; they are embedded within a broader interoceptive system through which the brain detects and interprets bodily states. This system supports allostasis, the brain’s predictive regulation of internal physiological demands. We propose a framework of interoceptive energy allostasis in which disruptions to these predictive processes contribute to the bidirectional relationship between depression and metabolic dysfunction. By integrating perspectives from metabolic and computational psychiatry, this framework offers a theoretical lens to explain the multidirectional comorbidity between mental and metabolic ill-health.

URL:

Authors:

Peng, T., GARCIA, C., Haneman, M., Shader, M.J., CARLYON, R.P., & McKay, C.M.

Reference:

Year of publication:

2025

CBU number:

9187

Abstract:

Purpose Variations in neural survival along the cochlear implant electrode array leads to off-place listening, resulting in poorer speech understanding outcomes for recipients. Therefore, it is important to develop and compare clinically viable tests to identify these patient-specific intra-cochlear neural differences. Methods Nineteen experienced cochlear implant recipients (9 males and 10 females) were recruited for this study. We estimated the neural health along the electrode array for a group of experienced adult implant recipients using two methods: the difference between psychophysical detection thresholds in bipolar vs. monopolar mode and the panoramic electrically evoked compound action potential method (PECAP). We hypothesised that: neural health estimated using both methods at single electrodes will be correlated at the participant level and the group level; and participants with larger variations in neural health along the electrode array will have poorer speech outcomes. Results At the individual level, the two neural measures correlated significantly across electrodes (p < 0.05) for 5 out of 15 participants. At the group level, we observed a weak but significant across-electrode correlation (R2 = 0.111, p < 0.001). While a larger variation in neural measures estimated from psychophysical thresholds was associated with lower phoneme speech scores (R2 = 0.499, p < 0.01), no significant association was found between variations in PECAP's neural health estimates and phoneme speech scores (R2 = 0.082, p = 0.366). Conclusion Our evidence suggests that both methods likely quantify a shared underlying neural basis, hypothesised to be the neural health along the cochlear implant array. The differences between the two measures may be attributed to differences in stimulus rate or loudness used to elicit responses and/or the influence of factors arising more centrally than the auditory nerve.

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Authors:

GARCIA, C., Morse-Fortier, C., GUERIT, F., Hislop, S., Goehring 3, CARLYON, R.P., & Arenberg, J.G.

Reference:

Year of publication:

2024

CBU number:

9186

Abstract:

Purpose: For some cochlear implants (CIs), it is possible to focus electrical stimulation by partially returning current from the active electrode to nearby, intra-cochlear electrodes (partial tripolar (pTP) stimulation). Another method achieves the opposite: "blurring" by stimulating multiple electrodes simultaneously. The Panoramic ECAP (PECAP) method provides a platform to investigate their effects in detail by measuring electrically evoked compound action potentials and estimating current spread and neural responsiveness along the length of the CI electrode array. We investigate how sharpening and broadening the electrical current spread are reflected in PECAP estimates. Methods: PECAP measurements were recorded at most comfortable level in 12 ears of Advanced Bionics CI users. Focused thresholds were also determined. For the electrodes with the highest and lowest focused thresholds, additional PECAP measurements were recorded while stimulating in pTP mode and in "blurred" mode with 3 or 5 adjacent electrodes simultaneously stimulated. Current spread and neural responsiveness were then estimated along the electrode array using PECAP. Results: PECAP revealed increased current spread estimates across participants for blurred stimulation of the targeted electrodes towards the apex of the cochlea. Variable results for pTP stimulation were found, with two of eight ears appearing to drive a small group-level effect of increased current spread. Conclusion: When stimulating multiple electrodes simultaneously, PECAP detected localized increases in current spread towards the apex (but not the base) of the cochlea. pTP stimulation showed mixed effects on PECAP current spread estimates. These findings are in line with behavioral speech perception studies and have implications for cochlear implant optimization

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Authors:

de Rijk, S.R., Boys, A.J., Roberts, I.V., Jiang, C., Garcia, C., Owens, R.M., Bance, M.

Reference:

Year of publication:

2023

CBU number:

9185

Abstract:

Cochlear implants are a life-changing technology for those with severe sensorineural hearing loss, partially restoring hearing through direct electrical stimulation of the auditory nerve. However, they are known to elicit an immune response resulting in fibrotic tissue formation in the cochlea that is linked to residual hearing loss and suboptimal outcomes. Intracochlear fibrosis is difficult to track without postmortem histology, and no specific electrical marker for fibrosis exists. In this study, a tissue-engineered model of cochlear fibrosis is developed following implant placement to examine the electrical characteristics associated with fibrotic tissue formation around electrodes. The model is characterized using electrochemical impedance spectroscopy and an increase in the resistance and a decrease in capacitance of the tissue using a representative circuit are found. This result informs a new marker of fibrosis progression over time that is extractable from voltage waveform responses, which can be directly measured in cochlear implant patients. This marker is tested in a small sample size of recently implanted cochlear implant patients, showing a significant increase over two postoperative timepoints. Using this system, complex impedance is demonstrated as a marker of fibrosis progression that is directly measurable from cochlear implants to enable real-time tracking of fibrosis formation in patients, creating opportunities for earlier treatment intervention to improve cochlear implant efficacy.

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Authors:

ShamsAlam, B., Farahani, H., WATSON, P., & Bagheri, S,

Reference:

Year of publication:

2025

CBU number:

9184

Abstract:

Background Shame, as a complex and global self-conscious emotion, plays a significant role in mental health. Self-criticism is a crucial factor in generating negative emotions, including shame, while self-compassion and self-forgiveness can mitigate the effects of self-criticism and shame. The present study examines the coexistence of these psychological constructs using a network analysis model. Methods A diverse sample of 474 Iranian residents, comprising men and women aged 13 to 73, participated in this study through convenience sampling. Variables were assessed using the External and Internal Shame Scale (EISS), the Self-Compassion Scale Short Form, the Levels of Self-Criticism Scale, and the Heartland Forgiveness Scale (HFS). Results We utilized a Graphical Gaussian Model (GGM) with polychoric correlations visualized using the qgraph, bootnet R packages and employed bridge centrality metrics along with permutation-based stability tests and bootstrap resampling to analyse the network's structure and stability. The network analysis revealed that nodes representing internalized self-criticism (IC), comparative self-criticism (CC), and self-forgiveness (SF) exhibited the highest bridge strength, indicating their critical roles in maintaining network connectivity. The network's stability was confirmed with a robust CS coefficient of 0.517, ensuring the reliability of these findings. Conclusion This network analysis provides a precise understanding of the relationships between shame, self-criticism, self-compassion, and self-forgiveness. In this study, comparative self-criticism and internal self-criticism emerged as critical factors in the regulation and generation of shame. Comparative self-criticism appears to play a more decisive role in the manifestation of shame.

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Authors:

MARTIN, J., MAVROGALOU-FOTI, A., ECK, J., Hattersley, L., Baker, K.

Reference:

Year of publication:

2025

CBU number:

9183

Abstract:

Background: Pathogenic CASK variants are associated with neurodevelopmental disorders of variable severity including X-linked intellectual disability (XLID) and microcephaly with pontocerebellar hypoplasia (MICPCH). Although the number of diagnosed cases is rising, current understanding of the CASK-related neurodevelopmental spectrum is limited. Here, we systematically review the published characteristics of individuals with CASK-related disorder, and compare these to a more recently-diagnosed group. We provide quantitative information about the ranges of adaptive abilities, motor function, visual function and social-emotional-behavioural characteristics, and explore within-group associations. Methods: 151 individuals with CASK variants were identified in published literature. 31 children and young people with CASK variants were recruited to the UK-based Brain and Behaviour in Neurodevelopmental disorder of Genetic Origin (BINGO) project. BINGO-participating caregivers completed a bespoke medical history questionnaire and battery of standardised neurodevelopmental measures. Results: Comparing the recently diagnosed BINGO CASK-related disorder group to previously reported individuals, we found consistent prevalence of tone abnormalities, sensorineural hearing loss and epilepsy, but lower prevalence of severe/profound ID, MICPCH, optic atrophy and nystagmus. Areas of frequent difficulty not highlighted in previous reports include sleep difficulties and cerebral visual impairment (CVI). Neurodevelopmental characteristics were highly variable within the BINGO CASK-related disorder group, and group-wide patterns were similar to those observed in other rare genetic conditions. Within the BINGO CASK-related group, epilepsy is significantly associated with ID severity, after controlling for age. Sub-groups with MICPCH or microcephaly only have equivalent ranges of adaptive function, but MICPCH may be associated with more severe motor difficulties. Conclusion: The spectrum of neurodevelopmental characteristics associated with CASK-related disorder appears to be broadening with increased access to genome-wide diagnostic testing. Further studies are needed to elucidate the relationships between CASK variants, structural brain development, epilepsy, and neurodevelopmental characteristics.

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Authors:

HUMPHREYS, G., LAMBON RALPH, M.

Reference:

Year of publication:

In Press

CBU number:

9182

Abstract:

Improving our understanding of the neural network engaged by different forms of speech production is a crucial step for both cognitive and clinical neuroscience. We achieved this aim by exploring two of the most commonly utilised speech production paradigms in research and the clinic, which have been rarely, if ever, compared directly: picture naming and category fluency. This goal was achieved in this two study investigation through a full ALE meta-analysis as well as a targeted fMRI study. Harnessing the similarities and differences between the two tasks offers a powerful methodology to delineate the core systems recruited for speech production, as well as revealing task-specific processes. The results showed that both tasks engaged a bilateral fronto-temporal speech production network, including executive and motor frontal areas, as well as semantic representational regions in the ATL, bilaterally. In addition, it was found that the extent of relative frontal lateralisation was task-dependent with the more executively-demanding category fluency task showing augmented left hemisphere activation. The results have implications for neurocomputational speech production models and the clinical assessment of speech production impairments. Data is available - https://osf.io/pe7un/

URL:

Data for this project is available at: https://osf.io/pe7un/

Authors:

VEDECHKINA, M., Holmes, J., Warrier, V. & ASTLE, D.

Reference:

Year of publication:

In Press

CBU number:

9181

Authors:

MARTIN, J., MAVROGALOU-FOTI, A., ECK, J., ,Hattersley, L., BAKER, K.

Reference:

Year of publication:

In Press

CBU number:

9180