Unilateral radiofrequency lesion versus electrostimulation of posteroventral pallidum: a prospective randomized comparison.

Microelectrode-guided posteroventral pallidotomy (PVP) has shown to be an effective method in the treatment of a group of patients with advanced Parkinson's disease. A nonlesioning approach by means of deep brain electrodes connected to a programmable neuropacemaker has also been used to inhibit the internal segment of globus pallidus (posteroventral stimulation [PVS]) reporting comparable clinical efficacy to the one obtained with the ablative method. Nevertheless, no controlled studies have been performed to compare the efficacy of both procedures. A prospective series of 13 patients with a clinical indication for globus pallidus surgery was randomized either to a pallidotomy or stimulator implantation, and comparisons on motor and neuropsychologic measurements were made on a 3-month follow-up basis. Primary measurements of efficacy showed a comparable effect on Unified Parkinson's Disease Rating Scale and activities of daily living score after both procedures. Secondary measurements of efficacy showed that although both techniques improve hand tapping score and dyskinesia score, the bilateral improvement in the former was greater after PVS whereas the latter improved more significantly after PVP. No significant changes in neuropsychologic parameters were observed after either PVP or PVS. Side effects and surgery complications occurred in six of 13 patients (three after PVP and three after PVS): they were mild, transient, and unrelated to optic tract injury. In conclusion, the short-time effect and safety of both procedures is comparable.

Role of the hypothalamic hamartoma in the genesis of gelastic fits (a video-stereo-EEG study).

Patients having a hypothalamic hamartoma frequently present epileptic attacks of laughter, and they later experience multiple additional seizure types, which invariably lead to a severe drug-resistant epilepsy. If this association is now well-known, relationships between the hypothalamic mass and the different types of seizures remain still mysterious. We report the case of a 16-year-old girl suffering from this peculiar epileptic picture, in whom a stereo-EEG study was performed, allowing us to record both the hamartoma, the neighboring hypothalamic structures, and other bilateral cortical areas. It showed that gelastic fits were strictly linked to ictal discharges which began and remained well localized in the hamartoma. Conversely, atonic seizures, which might result from a secondary epileptogenesis, admitted a widely extended bilateral frontal cortical origin, sparing the lesion, and slightly involving the posterior hypothalamus. Stereotactic radiosurgery of the hamartoma proved to be ineffective on both types of seizures, probably because of the too low dose of X-rays delivered (18 grays), as suggested by the absence of hypothalamic mass changes on MRI. Such data, never reported to our knowledge, seem able to contribute to a better understanding of this very peculiar epileptic syndrome, and perhaps to a better adapted therapeutic management.

Circadian patterns of growth hormone, prolactin and corticotrophin secretion in hypothalamic and extra-hypothalamic lesions localized by stereotactic neuro-radiology in humans.

The integrity of mediobasal hypothalamus for the maintenance of normal circadian rhythms has been clearly established in the animal. Using precise stereotactic neuroradiologic localisations of various brain tumors, the authors demonstrate that in human, cortical lesions induce no significant modifications of the circadian variation of GH, prolactin or ACTH. In contrast subcortical lesions displacing the 3rd ventricle result in an inhibiton of the nocturnal rise in GH and prolactin, whereas the circadian rhythm of ACTH remains normal.

Stereotactic hypothalamotomy for behaviour disorders.

Posterior hypothalamotomy is a relatively simple stereotactic procedure. The radiological determination of the target and its physiological corroboration by electrical stimulation are accurate. The lesions have always been made in the site of maximum sympathetic response. In this respect, the cardiovascular changes (hypertension and tachycardia), which are always elicited from a more restricted area, are of particular importance. Depth recordings, however, have been less useful. Undesirable side-effects, if present, were mild and transitory. There was no postoperative intelligence deficit, at least with the standard tests.