Cortical silent period in two patients with meningioma and preoperative seizures: a pre- and postsurgical follow-up study

Objectives: Prolongation of the cortical silent period (CSP) following transcranial magnetic stimulation has been reported in patients with partial epilepsy involving the primary motor cortex (M1). This study aimed to investigate the relationship between the expected intraindividual variations in risk factors for seizures and CSP duration. Methods: We studied a 59-year-old woman with a rolandic meningioma and simple motor partial seizures and a 71-year-old woman with a parietal/occipital meningioma and complex partial seizures. Both patients had seizure as their initial symptom with complete postsurgical remission. Repeated pre- and postoperative CSP recordings were made from both first dorsal interosseous muscles. We compared the results to those obtained in 13 normals. Results: In the patient with simple motor partial seizures, the CSP was significantly prolonged in preoperative recordings and 3 weeks after surgery. This CSP lengthening partly subsided 3 months after surgery. Finally, the CSP was normal 6, 8, and 18 months after surgery. In the patient with complex partial seizures, no CSP change was observed. Conclusions: In our patient with a rolandic meningioma, CSP prolongation was observed when the risk of seizure relapse was supposed to be higher (preoperative and early postoperative periods). This supports the view that CSP changes reflect compensatory mechanisms in M1 epilepsy.