5 April 2018
Comparing visuospatial associative learning for a middle-aged birth cohort and patients with schizophrenia
Visuospatial memory is extremely heterogeneous in schizophrenia. In a large population study, around a fifth of patients with schizophrenia showed similar errors rates to the top 50% of the general population. Conversely, half of the patients sampled showed substantial impairments.
- In the general population, visuospatial associative learning can start to decline from the age of 40.
- Previous studies have shown that this cognitive function is substantially impaired in many patients with schizophrenia.
- Scientists at Cambridge Cognition compared visuospatial memory for middle-aged, typically-developing adults and patients with schizophrenia.
- The study included a total of >5000 participants drawn from the:
- Northern Finland Birth Cohort 1966 (NFBC66), a general population sample.
- Finnish SUPER study of schizophrenia, part of the Stanley Global Neuropsychiatric Genomics Initiative.
- Visuospatial memory was assessed using the CANTAB Paired Associative Learning (PAL) Test, as shown in figure 1. The primary outcome variables were:
- ‘Total errors adjusted’ (TEA): the total number of times the participant selected the incorrect box, adjusted for trials not completed due to early termination.
- ‘First attempt memory score’ (FAMS): the total number of correct choices made by the participant on the first attempt of the trials.
- Compared with the general population, the SUPER sample of patients with schizophrenia made less than half as many correct first choices (FAMS) on average.
- This pattern was mirrored in TEA. On average, the SUPER sample made more than twice as many errors (TEA) than the general population.
- However, the distribution of scores was very different between the two groups, as visualized in figure 2.
- Visual memory is extremely heterogeneous in schizophrenia. Performance is characterized by a multimodal distribution which is not seen in the general population.
- Around a fifth of patients with schizophrenia had error scores similar to the top 50% of the general population, while around half showed a substantial impairment.
Dr Jenny Barnett, CSO