Cognitive Neuropsychology of Ageing in Schizophrenia

Coordinating Institution: CRP Sante
From: 01/10/2004
To: 30/09/2007
Budget: 151,603.00€
Contact(s): Pull Charles , Schuller Anne-Marie

Summary

Schizophrenia is a severe psychiatric illness found in about 1% of the population. This chronic pathology starts generally in early adulthood and is characterised by positive symptoms such as delirium or hallucinations and by a negative symptomatic, such as social retreat or apathy. Further more, cognitive impairments are part of the core feature of schizophrenia, both at disease onset, or even before, and after many years of treatment. Neuroimaginery studies have now well established the presence of structural brain abnormalities and the underlying neuropsychological impairments although performance impairments are widespread.

Considering that in normal aging changes in cognition and in every day functioning are also occurring, how are the cognitive impairments in schizophrenia evolving across a lifespan of illness? Is schizophrenia a deteriorating process or is it better considered as an static encephalopathy?

This cross-sectional study aims to evaluate the cognitive, functional and neuroanatomical correlates during aging in schizophrenia. In collaboration with the Hôpital Civil de Strasbourg, a total of 108 elderly participants was tested in this study. The sample was composed of patients suffering from schizophrenia and matched healthy controls, and was evaluated with an extensive neuropsychological battery, including tests of short and long term memory, executive functioning, language, attention, intelligence and global functioning. In partnership with the Centre Hospitalier Neuropsychiatrique (CHNP), twenty-five persons from 50 to 82 years suffering from chronic schizophrenia could be recruited in Luxembourg. IRM data could be acquired from a total sample of 68 participants (40% patients).

The results of the neuropsychological evaluation show an interaction between age and pathology, as measured on the global cognitive functioning scales as the MMS and Mattis dementia scale. These data show a significantly marked deterioration in performance with progressing age in schizophrenic patients compared to healthy controls.

To this point of the IRM analyses, the results of the voxel-based morphometry show structural differences in the brain of the persons suffering from schizophrenia compared to the healthy controls. A density reduction of the gray matter volume is observed in frontal and superior temporal regions of the patients’ brains. A clear difference is also found in the central sub-lobar region, probably reflecting a dilatation of the ventricles (see fig.1). These differences have been classically reported in studies on young schizophrenic patients (eg. Honea et al 2005). Surprisingly, we find also gray matter differences in the occipito-parietal regions. Further studies should confirm if this gray matter reduction might be specific for the aging process in schizophrenia.

Fig. 1a): Clock drawing of a control subject, and b) of a 54 year old patient suffering from schizophrenia. Notice the additional digit (13), an irrelevant spatial organization and a wrong position of one hand (the task was to draw “ten minutes after eleven”), pointing literally to 10.

Fig. 1: Differences in gray matter (GM) segmentation between the control group and the patient group. The colored regions suggest a reduction of the mean GM volume in the patient group (p < 0.001 et k=1000).