Abstracts

Rationale: We report the cognitive outcome of the first patients to undergo stereotactic laser ablation (SLA) of cavernous malformations in an effort to control intractable seizures. We have recently demonstrated that this approach appears feasible, safe, and effective for seizure reduction. We predict focal cognitive decline will occur when ablations are completed in eloquent brain regions, as the general approach is to ablate slightly beyond the hemosiderin rim of these structural abnormalities. Methods: We compare the pre- to 6-month postsurgical neuropsychological data for the initial 4 patients undergoing SLA of cavernous malformations at Emory University using reliable change indices (RCI) or standard based regression (SBR) scores on a wide range of clinical and experimental measures. Locations of the cavernous malformations included: (a) right frontal lobe, (b) white matter of left fusiform gyrus (2 patients), and (c) right hippocampus (See Figure 1). Results: At 6-month follow-up, all 3 patients with temporal lobe (TL) lesions were seizure free, while the one frontal lobe (FL) case continued to experience seizures, and will now undergo open resection. Focal deficits occurred in all 3 TL cases, while the FL patient showed no decline on any measure. Significant improvements were observed in all 3 TL cases in cognitive functions thought to be more globally represented (e.g., attention, processing speed), related to improvement in performance for focal regions distal from the onset zone (e.g., executive function), and even some functions on the side of the ablation, which are known to be at risk with open resection. For example, both patients with ablations involving the left fusiform gyrus experienced significant declines in famous face naming and verbal list recall, despite sparing or improvement in naming common objects and other aspects of verbal memory and language. Conclusions: These results suggest: (1) cognitive deficits following SLA of cavernous malformations may be focally restricted to structure-function changes associated with ablations of eloquent brain regions; (2) global improvement frequently occurs with such ablations, likely related to improved performance in areas distal to the seizure onset zone following improved seizure control; (3) future studies are needed to compare the cognitive outcome of open resection to the SLA procedure with this neurological subgroup; and (4) the SLA procedure holds promise for studying the brain with very focal lesions never before achievable in humans.