Neural correlates of processing harmonic expectancy violations in children and adolescents with OCD

A Systematic Review of Scientific Studies and Case Reports on Music and Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a severe psychiatric disorder, which can be associated with music-related symptoms. Music may also be used as an adjunct treatment for OCD. Following the PRISMA guidelines, we performed a systematic literature review exploring the relationship between music and OCD by using three online databases: PubMed, the Web of Science, and PsycINFO. The search terms were "obsessive compulsive disorder", "OCD", "music", and "music therapy". A total of 27 articles were utilised (n = 650 patients/study participants) and grouped into three categories. The first category comprised case reports of patients with musical obsessions in patients with OCD. Most patients were treated with selective serotonin reuptake inhibitors (SSRIs) or a combination of an SSRI and another pharmacological or a non-pharmacological treatment, with variable success. Studies on the music perception of people with OCD or obsessive-compulsive personality traits represented the second category. People with OCD or obsessive-compulsive personality traits seem to be more sensitive to tense music and were found to have an increased desire for harmony in music. Three small studies on music therapy in people with OCD constituted the third category. These studies suggest that patients with OCD might benefit from music therapy, which includes listening to music.

Sensory Habituation as a Shared Mechanism for Sensory Over-Responsivity and Obsessive-Compulsive Symptoms

Background

Some individuals who suffer from obsessive-compulsive (OC) disorder (OCD), report disturbing sensory preoccupations. The inability to stop obsessing over stimuli resonates with a difficulty in sensory habituation. Impaired sensory habituation, to a degree that clearly dysregulates response to sensory stimuli, and impairs participation in everyday activities, can be part of a disorder known as sensory over-responsivity (SOR). Although previous studies indicated a correlation between OCD and SOR, physiological experiments show that individuals with OCD are not more sensitive to sensory stimuli than controls. In the current study, we (1) validated a sensory habituation psycho-physiological protocol and (2) tested whether a "slow to habituate" mechanism can explain the occurrence of elevated SOR and OC symptoms.

Methods

We designed a protocol to test auditory sensory habituation through electrodermal activity (EDA) recording. The protocol included two randomly ordered aversive and neutral sound conditions; each set of six everyday life sounds was presented as a continuous stimulus. During the presentation of sounds, EDA was measured and participants could press a button to shorten the stimuli. Participants also completed sensory and OC symptom questionnaires. Participants included 100 typically developing adults that were divided into high versus low OC symptom groups. Mixed models analysis was used throughout to meet the need for capturing the temporal nature of habituation.

Results

Distinct physiological indices were computed to measure sensitivity versus habituation. Habituation was slower in the aversive versus neutral condition. Sensitivity was higher for the aversive stimuli. Self-report of sensory habituation and sensitivity partially correlated with the physiological habituation indices. A comparison of the physiological pattern between those with high versus low OC symptoms revealed significant differences in the habituation and sensitivity indices, across conditions.

Conclusion

The interplay between SOR and OC symptoms can be explained by a "slow to habituate" mechanism. Identifying behavioral and physiological markers of sensory problems in OCD is important for assessment, intervention and the discovery of underlying mechanisms.

Neural correlates of prediction violations in boys with Tourette syndrome: Evidence from harmonic expectancy

OBJECTIVES

It has been suggested that Tourette syndrome (TS) might be associated with alterations of the attention system, but the nature of these alterations and the underlying neuroanatomical network remains elusive. We aimed at investigating the functional neuroanatomical modulators of attention allocation towards predictable versus unpredictable stimuli in boys with TS.

METHODS

Using functional magnetic resonance imaging, we ran a harmonic expectancy violation paradigm in 17 boys with TS and 23 matched healthy controls (HCs). We presented chord sequence in which the first four chords induced a strong expectancy for a harmonic chord at the next position. In 70% this expectancy was fulfilled (harmonic), in 30% the expectancy was violated (disharmonic).

RESULTS

HCs responded faster to the disharmonic compared to harmonic chords, indicating a stronger attention allocation towards unpredictable stimuli, while this effect was not found in boys with TS. HCs showed stronger anterior cingulate cortex (ACC) activation during disharmonic compared to harmonic chords. Boys with TS showed stronger ACC activation during harmonic chords, which was associated with greater tic severity.

CONCLUSIONS

Our findings indicate that boys with TS showed altered reactions towards predictable versus unpredictable stimuli in brain regions playing an important role in attention control. This might indicate altered allocation of attention towards those stimuli.