Differential spatial memory impairment after right temporal lobectomy demonstrated using temporal titration

In this study a temporal titration method to explore the extent to which sp atial memory is differentially impaired following right temporal lobectomy was employed. The spatial and non-spatial memory of 19 left and 19 right te mporal lobectomy (TL) patients was compared with that of 16 normal controls . The subjects studied an array of 16 toy objects and were subsequently tes ted for object recall, object recognition and memory for the location of th e objects. By systematically varying the retention intervals for each group , it was possible to match all three groups on object recall at sub-ceiling levels. When memory for the position of the objects was assessed at equiva lent delays, the right TL group revealed disrupted spatial memory, compared with both left TL and control groups (P < 0.05). MRI was used to quantify the extent of temporal lobe resection in the two groups and a significant c orrelation between hippocampal removal and both recall of spatial location and object name recall in the right TL group only was shown. These data sup port the notion of a selective (but not exclusive) spatial memory impairmen t associated with right temporal lobe damage that is related to the integri ty of the hippocampal functioning.