Biology subjects

Hobeika, L.

Publications and source records attributed to Hobeika, L..

3 recordsLinked to original sources

bioRxiv2025

Tinnitus perception is linked to arousal system dysfunction

Tinnitus, the perception of sound in the absence of an external source, affects 14% of the population and is often associated with concentration and emotional difficulties. However, the characterization of the associated cognitive difficulties remains unclear. We hypothesize that attentional complaints are due to a dysfunction of the exogenous or endogenous orientation of attention, or of the arousal system. In this study, 200 participants (100 with chronic tinnitus and 100 matched controls) completed a battery of cognitive tasks assessing attention, alertness and executive functions, including the Attentional Network Task (ANT), Sustained Attention to Response Task (SART) with mind wandering evaluations, Stroop, and Trail Making Test. Tinnitus comorbidities, including hearing loss, sleep quality, anxiety, and hyperacusis were controlled. The results showed that individuals with tinnitus had a reduced sensitivity to alert signals, and lower sustained attention abilities, both suggesting lower levels of arousal. Mind-wandering analyses revealed fewer planning-related thoughts in the tinnitus group, suggesting higher needed cognitive resources to perform the task. Contrary to prior findings, we found no evidence of deficits in executive functioning specific to tinnitus; rather, executive impairments were associated with hearing loss and sleep disturbances. Overall, these findings support the hypothesis that tinnitus is linked to a dysfunction in the arousal system--likely involving the locus coeruleus-noradrenergic network. This work proposes a new theoretical framework implicating arousal dysregulation as a core mechanism in tinnitus-related cognitive complaints. Significance StatementTinnitus, the perception of sound without an external source, affects millions worldwide and is often accompanied by concentration difficulties. By rigorously controlling for hearing loss, sleep deprivation, and anxiety, we isolate the core cognitive changes linked to tinnitus itself. Our study reveals that attentional deficits in tinnitus primarily arise from dysregulation in the brains arousal system. We propose a novel integrative framework in which arousal system dysfunction underlies the cognitive and emotional symptoms associated with tinnitus, providing a new perspective for understanding the complex interactions between attention, sleep, and anxiety in this condition.

neuroscience↗

bioRxiv2023

Sensorimotor Impairment in Ageing and Neurocognitive Disorders: Beat Synchronisation and Adaptation to Tempo Changes

BackgroundUnderstanding the nature and extent of sensorimotor decline in ageing individuals and those with neurocognitive disorders NCD, such as Alzheimers disease, is essential for designing effective music-based interventions. ObjectiveOur understanding of rhythmic functions remains incomplete, particularly in how ageing and NCD affect sensorimotor synchronisation and adaptation to tempo changes. This study aims to fill this knowledge gap. MethodsPatients from a memory clinic participated in a tapping task, synchronising with metronomic and musical sequences, some of which contained sudden tempo changes. After exclusions, 51 patients were included in the final analysis. ResultsParticipants mini-mental state examination scores were associated with tapping consistency. Additionally, age negatively influenced consistency when synchronising with a musical beat, whereas consistency remained stable across age when tapping with a metronome. ConclusionsThe ability to extract a beat from a musical signal diminishes with age, whereas the capacity to maintain a beat remains relatively constant. However, both processes may decline at moderate or severe stages of NCD. Moreover, the results indicate that the initial decline of attention and working memory with age may impact perception and synchronisation to a musical beat, whereas progressive NCD-related cognitive decline results in more widespread sensorimotor decline, affecting tapping irrespective of audio type. These findings underline the importance of customising rhythm-based interventions to the needs of older adults and individuals with NCD, taking into consideration their cognitive as well as their rhythmic aptitudes. This study was registered at clinicaltrials.gov (NCT04146688).

neuroscience↗

bioRxiv2019

Capturing the dynamics of peripersonal space by integrating sound propagation properties and expectancy effects

HighlightsO_LILogarithmically distributed auditory distances provides an apt granularity of PPS\nC_LIO_LIMeasuring expectation helps to interpret behavioral impact of audiotactile integration\nC_LIO_LITactile RTs follows a logarithmic decrease due to audiotactile integration\nC_LIO_LIPeripersonal space is better characterized and quantified with this refinement\nC_LI\n\nBackgroundHumans perceive near space and far space differently. Peripersonal space, i.e. the space directly surrounding the body, is often studied using paradigms based on auditory-tactile integration. In these paradigms, reaction time to a tactile stimulus is measured in the presence of a concurrent auditory looming stimulus.\n\nNew MethodWe propose here to refine the experimental procedure considering sound propagation properties in order to improve granularity and relevance of auditory-tactile integration measures. We used a logarithmic distribution of distances for this purpose. We also want to disentangle behavioral contributions of the targeted audiotactile integration mechanisms from expectancy effects. To this aim, we added to the protocol a baseline with a fixed sound distance.\n\nResultsExpectation contributed significantly to overall behavioral responses. Subtracting it isolated the audiotactile effect due to the stimulus proximity. This revealed that audiotactile integration effects have to be tested on a logarithmic scale of distances, and that they follow a linear variation on this scale.\n\nComparison with Existing Method(s)The granularity of the current method is more relevant, providing higher spatial resolution in the vicinity of the body. Furthermore, most of the existing methods propose a sigmoid fitting, which rests on the intuitive framework that PPS is an in-or-out zone. Our results suggest that behavioral effects follow a logarithmic decrease, thus a response graduated in space.\n\nConclusionsThe proposed protocol design and method of analysis contribute to refine the experimental investigation of the factors influencing and modifying multisensory integration phenomena in the space surrounding the body.

neuroscience↗