Biopsy and post-mortem findings in a patient receiving cerebellar stimulation for epilepsy.

Abstract

equipment was accurately calibrated. The functioning of the stimulating equipment was regularly reviewed and reasonable estimates of the charge density at the cerebellar surface and the total charge delivered to the cerebellum are therefore available. Case historyThe patient, (SB, born 8/1/55), was 24 years old at the time of his admission to the Southampton cerebellar stimulation trial. His epilepsy began at the age of seven years and there were no predisposing factors. He suffered from grand mal epilepsy, complex partial epilepsy and petit mal epilepsy. The grand mal attacks occurred rarely, but could be severe and prolonged. Complex partial attacks occuffed up to five times a day and the petit mal attacks up to forty or more in a day. Medication consisted of phenytoin 200 mg twice daily and carbamazepine 200 mg four times a day and he had been on this combination for over six months before admission. It was considered the best combination and the optimal dosage and gave serum levels of phenytoin 1-3 mg/100 ml and carbamazepine 0-7 mg/100 ml. Previously he had, at different times, been treated with these drugs in different dosages and with primidone.At operation on 20 March 1979 under general anaesthesia, two eight-button electrode pads with an electrode surface area 32 mm2 (Avery Laboratories Inc) were placed

Modulation of epileptic activity by deep brain stimulation: a model-based study of frequency-dependent effects

“…Since the early 90s, neurologists also attempted to apply DBS to other neurological disorders, typically to intractable epilepsies in order to suppress—or at least dramatically reduce—the occurrence of seizures [see recent review in Boon et al (2009)]. These studies followed early scientific evidence showing potentially beneficial effects of DBS on epileptic neural dynamics in animal models (Reimer et al, 1967; Hablitz, 1976) as well as in patients (Cooper et al, 1973; Davis et al, 1982; Wright and Weller, 1983). However, contrary to PD, the optimal “antiepileptic parameters” of DBS for reducing the frequency of seizures are much more variable among patients and the number of non-responders to stimulation still perplexes scientists.…”

Histological Alterations Induced by Electrode Implantation and Electrical Stimulation in the Human Brain: A Review

“…A postmortem histological analysis was performed in 10 patients. These patients suffered from epilepsy ( N = 6) (13,16–18), CP ( N = 2) (15), or amyotrophic lateral sclerosis ( N = 1) (19). In one patient, the indication for cerebellar stimulation was not reported (20).…”

“…In one of these autopsied patients, a biopsy was taken during the implantation, making within‐subject comparison possible between nonstimulated and stimulated cerebellar cortex (18). In four other patients (CP or other movement disorders), a biopsy was taken during implantation of the electrode and another several months later, after stimulation (11,12,14).…”

“…Encapsulation or adhesion of the electrode to underlying tissue also was observed in five other studies (Table 1). This connective tissue was at least half of the thickness of the dura of the tentorium (16) and was highly vascularized (17,18). Many of the venules were either largely dilated or collapsed and numerous arterioles showed hyalinization of the tunica media (= middle layer of the arterial wall) (17).…”

Electrical stimulation devices in the treatment of epilepsy

“…With respect to future prospects it is encouraging that cerebellar stimulation appears to be safe: there is a small risk of bleeding (0.6%) and wound infection (2.7%) [18]. The autopsy of one patient with chronic cerebellar stimulation for 16 months found non-specific fibrosis over the electrodes: there was no underlying neuronal loss, suggesting that long-term electrode implantation does not damage microscopic cerebellar structure [92]. Further research is needed to resolve the uncertainty of whether cerebellar stimulation is effective in humans.…”