Voice Hearing

Voice Hearing Continuum

Voice hearing exists on a spectrum and is not limited to clinical populations. It involves a range of experiences, from hearing one’s name to complex dialogues, and can be distressing or benign. Neuroscientific and psychological studies have explored its neural and cognitive correlates, and cultural factors also play a role. Understanding this spectrum has implications for mental health treatment, challenging associated stigma and informing therapeutic interventions.

At LISN, our research focuses on cognitive abilities and biases predictive of voice hearing tendencies across this spectrum. We particularly examine signal detection theory (SDT) performance, where both nonclinical and clinical voice hearers often exhibit an externalising bias, perceiving internal voices as originating externally. By comparing SDT performance among individuals, we aim to understand how this bias may be influenced by auditory verbal hallucination (AVH) proneness, variations in corollary discharge, memory inhibition, and other individual factors. Through this focus, LISN aims to offer a nuanced understanding of the cognitive mechanisms underlying the voice hearing spectrum.

Voice Hearing as Predictions

Voice hearing has been increasingly studied within the predictive coding framework, which describes perception as a process of hypothesis testing. In this framework, auditory verbal hallucinations (AVH) may arise from an imbalance between top-down predictions and bottom-up sensory input. Research has explored various factors contributing to this imbalance, such as neurotransmitter systems, cognitive biases, and socio-emotional factors. This perspective offers a generalised understanding of voice hearing and opens new avenues for prognosis, diagnosis and treatment.

At LISN, we focus on experimentally manipulating predictions and sensory input to understand voice hearing better. Methods include conditioning, articulatory suppression, earworm induction, and exposure to different types of auditory noises. We assess the impacts of these manipulations on signal detection task (SDT) performance and self-reported voice hearing experiences (Mak et al., 2023). The goal is to test whether voice hearing can be causally explained in terms of changes in predictive brain mechanisms, which are natural, inherent mechanisms of the brain. Through this research, LISN aims to develop methods to characterise voice hearing tendencies across the population. This will help us understand its prevalence and transition risks to psychosis, while also helping to de-stigmatise the condition, especially among young people and those from ethnic minority backgrounds.

Voice Hearing Transition Risks

The transition from voice hearing to psychosis is a critical but relatively uncommon area of study in mental health research. While many people experience voice hearing without transitioning to clinical states like psychosis, understanding the factors that contribute to this transition is crucial for early intervention. Research has identified risk factors such as frequency and distress level of voice hearing, comorbid symptoms, and environmental stressors. Neurobiological markers and the concept of a “clinical high-risk state” have also been studied to identify those at increased risk.

At LISN, we aim to understand the transition risks among nonclinical voice hearers, in collaboration with the Greater Manchester Mental Health NHS Foundation Trust. Our research focuses on understanding these risks as neurodevelopmental vulnerabilities, reflected in progressive voice hearing experiences. We also aim to understand the underlying cognitive and neural mechanisms that contribute to this transition. Through this targeted research, LISN seeks to offer insights into the factors that may lead to the transition from voice hearing to psychosis, with the goal of informing early intervention and prevention strategies.

Voice Hearing Interventions

Interventions for voice hearing have evolved to include a range of approaches, from pharmacological treatments to psychological therapies like CBT and mindfulness. Emerging techniques like neurostimulation and neurofeedback offer targeted, brain-based interventions. Neurostimulation methods like TMS and tDCS modulate neural activity, while neurofeedback teaches self-regulation through real-time brain monitoring. These methods are less reliant on medication and offer the promise of more personalised treatment.

At LISN, our focus is on developing an EEG-tDCS closed-loop type of online intervention for voice hearing. The EEG identifies the states of voice hearing in real-time, and tDCS aims to counter it before it escalates into full-blown psychotic episodes. While these are still drawing board ideas, they represent the ultimate goal of our lab in studying voice hearing. Through this innovative approach, LISN aims to offer a more immediate and targeted intervention, potentially revolutionising the treatment landscape for voice hearing.