Auditory hallucinations: phenomenology, neuropsychology and neuroimaging update

Abstract

Auditory verbal hallucinations (AVHs) are a cardinal feature of psychosis. Recent research is reviewed which has attempted to advance our knowledge of the mechanisms underlying this symptom. Phenomenological surveys have confirmed the importance of the content of such hallucinations and their meaning to the voice‐hearer. Psychological and neuroimaging studies of inner speech and source monitoring have provided a neuropsychological framework for AVHs as well as some novel therapeutic strategies. There have also been successful attempts to ‘capture’ neural activity coincident with the experience of hallucinations using PET, SPECT and functional magnetic resonance imaging (MRI). This body of knowledge in combination with work on in‐vivo receptor binding (dopamine and GABA) provides the beginnings of a cognitive and ncurophysiological understanding of this complex and intriguing phenomenon.

Hearing of a Presence

“…Even if in rare instances external AVHs may be lateralized and localized, their spatial attributes are extremely variable. They are experienced at variable distances and variable locations from the patients' bodies and often described at delusional locations (Chadwick and Birchwood, 1994;Nayani and David, 1996;David, 1999). Our patient, on the contrary, experienced all HPs at the same location and distance from her body (on the same side where a deficit for the localization of sound sources was found and where the FP as well as arm dislocation occurred, see below).…”

“…Complex auditory hallucinations cover a variety of experiences, but are most often characterized by the hearing of a ''voice or voices'' called auditory verbal hallucinations (AVH). AVHs are frequent in psychotic patients (Lowe, 1973;Junginger and Frame, 1985;Chadwick and Birchwood, 1994;David, 1999;Nayani and David, 1996) and have also been induced artificially by electrical stimulation of the temporal lobe in epileptic patients (Penfield and Perot, 1963;Gloor et al, 1982). However, psychotic patients often find it difficult to say whether the ''voice'' is inside or outside their head (Nayani and David, 1996;David, 1999) and mostly experience AVHs inside their head or body (Junginger and Frame, 1985;Chadwick and Birchwood, 1994;Nayani and David, 1996).…”

Brain correlates of subjective reality of physically and psychologically induced pain

“…Ability to differentiate real and imaginal percepts, however, can be distorted in patients suffering from various organic and functional brain disorders and occasionally even in healthy subjects (1)(2)(3).…”

“…Because the clarity of a percept likely affects the experience of its reality, and because both real and hallucinatory percepts may be associated with activation of sensory brain areas (10,11), we hypothesized that a neuronal system subserving the SRP should involve components that process pain-related sensory-discriminative information, i.e., the primary and secondary somatosensory cortices and the posterior insula (12,13). We also expected this system to include brain regions such as the perigenual anterior cingulate cortex (pACC) (14) that are able to support source monitoring, because a failure to differentiate between internal and external sources has been argued to be essential for hallucinations (1,2).…”

Entendre des voix : nouvelles voies ouvrant sur la pratique et la recherche

“…D'autres systèmes dont le système auriculaire peuvent être atteints. Des études de chercheurs de l'Institut de psychiatrie de Londres (David, 1999 ;Johns et al, 2001 ;McGuire et al, 1995) ont montré une réduction de l'activation corticale de régions du lobe temporal gauche impliquées dans le discours intérieur chez les personnes ayant des HA ; ces personnes seraient ainsi incapables de discerner que le discours intérieur provient d'elles et l'interprètent comme venant de l'extérieur. Les études rapportées par O'Connell et al (1997) vont dans le même sens et suggèrent que les personnes entendant des voix auraient une déficience au plan du cortex qui ferait en sorte que l'intégration de réseaux neuronaux entre les lobes frontal et temporal serait affectée.…”