SPET STUDY OF VERBAL FLUENCY IN SCHIZOPHRENIA AND EPILEPSY

Background The association between temporal lobe epilepsy and schizoph renia suggests that the critical abnormality may be pathology within t he temporal lobes. People with schizophrenia-like psychosis of epileps y (SLPE) provide a useful group in which to examine the importance of temporal and frontal lobe dysfunction in schizophrenia. Method A verba l fluency activation paradigm and a Te-99m HMPAO SPET were used to stu dy frontotemporal function in people with SLPE (n=12), schizophrenia ( n=11)and epilepsy (n=16). Results People with SLPE differed from both other groups by showing lower blood flow in the left superior temporal gyrus during performance of a verbal fluency task compared with a wor d repetition task (F=5.4, P=0.0 I). During the verbal fluency task peo ple with primary schizophrenia showed a greater increase in blood now in anterior cingulate (F=4.5, P=0.02) than the other two groups.There were no between-group differences in frontal brain regions. Conclusion Our findings support an association between left temporal lobe abnorm ality and SLPE.The different patterns of activation observed in people with primary schizophrenia and SLPE suggests that different pathophys iological mechanisms may operate in these two groups. In SLPE the path ophysiology may be relatively confined to the dominant temporal lobe.