Auditory Processes and Emotional Perception in Schizophrenia

The main objective of this study is to study the links between source memory deficits and externalization abilities in schizophrenic patients and healthy subjects.

Also, this study will:

• evaluate the impact of emotional content on the ability to externalize an auditory perception
• evaluate the abilities to separate sources concerning vocal stimuli
• evaluate the basic auditory processes In order to meet the objectives, the correlation between the percentage of good attributions in the reality monitoring task and the percentage of correct perceptions in/out (sound perceived as coming from inside or outside the head) will be analyzed in the externalization task in patients suffering from schizophrenia.

Will also be analyzed:

• the number of correct perceptions In/Out in the externalization task
• the number of correct perceptions In/Out for the emotional stimuli
• the detection level of difference in pitch between 2 vocal sources pour the height discrimination task
• the number of correctly identified words in the speech-in-speech task

The tasks :

Subjects will undergo a battery of cognitive and auditory experiments in order to answer the objectives and hypothesis. The duration of the entire experiments will be 3.30 hours.

• Subjects will undergo the source monitoring task (30 min):

This task is divided in 2 parts:

• one part that will evaluate the reality monitoring performances (LISTENING task). Subjects either have to listen to words or imagine themselves listening to words
• another part evaluating internal source monitoring performances (SAY task). Subjects either have to pronounce words or imagine themselves pronouncing words.

• In order to measure perception abilities, all subjects will undergo a battery of psychoacoustic tests (30 min) including the Tone Matching Task (TMT) which evaluates the capacity of discriminating static pitch. The battery is also composed of tasks measuring length, amplitude, etc…
• A yes / no discrimination task will be used to measure the externalization abilities: subjects will have to discern whether a sound is perceived as coming from inside or outside the head
• the ability to separate sources will be measured using 2 paradigms:
• a pitch discrimination task (30 min): it will evaluate the capacity to discern sources based on voice pitch
• a speech-in-speech task (30 min): target words are presented simultaneously to masks (composed of words time reversed so that have lost the semantic content). The subject has to listen and repeat the words heard.

Inclusion criteria

Subjects aged between 18 and 65 years old - written given consent

For patients with schizophrenia:

• that meet the DSM-5.0 schizophrenia criteria

For healthy control subjects:

• absence of psychiatric disroders (past and actual) diagnosed according to the DSM-5.0
• absence of prodromal psychosis as measured by a score under 6 at the Prodromal Questionnaire PQ-16 (Ising et al., 2012)
• absence of auditory disorders (actual and past) (including tinnitus)
• absence of medical treatment (to the exception of contraceptive pills

Exclusion criteria

• history of neurological disorders or brain injury with loss of consciousness
• subjects presenting with highly developed musical abilities (frequently practicing a musical instrument)
• subjects presenting with an intellectual deficiency as measured by the Raven progressive matrices
• subjects under guardianship