[Production of rhythms in schizophrenia: the central role of attention]

Schizophrenia is a psychiatric illness that is characterised by a deficit in the fluent sequencing of thought and action. This problem of discoordination might be due to unreliable timing processes associated with a difficulty in allocating sufficient attention. In the present study, we placed ourselves within the hypothesis that schizophrenic patients may have difficulties in producing rhythmic tapping actions and that this deficit may be correlated with the degree of attention abnormalities.

Subjects were required to tap in rhythm with alternating force levels and/or alternating time intervals (<1s) during trials lasting 24s. In addition, all patients performed an attention task (D2 test). A qualitative analysis of the tap trials was conducted in order to characterise the nature of the deficits that patients revealed.

Results showed that all patients revealed significant difficulties in performing the tapping trials. The number of trials removed was correlated with the level of attention dysfunction. Finally, our qualitative analysis revealed that 60% of patients presented attentional lapses - which were never observed in the healthy controls.

This study revealed deficits in the timing of action that resemble, at least on a behaviour level, the clinical lapses observed in schizophrenia. These lapses seem to be correlated to the degree of attention deficits. Future studies are now required in order to gain better understanding of the nature of the attention deficits in schizophrenia. More specifically, a better definition of the possible functional relationship between clinical lapses, cognitive lapses and action freezing is needed to develop innovating tools for rehabilitation.