The role of ghrelin, neuropeptide Y and leptin peptides in weight gain after deep brain stimulation for Parkinson's disease.

BACKGROUND: The exact mechanism of weight gain (WG) after deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients with idiopathic Parkinson's disease remains unknown. OBJECTIVES: To investigate a possible involvement of ghrelin, neuropeptide Y (NPY) and leptin in WG after DBS. METHODS: Twenty-three Parkinson patients were submitted for body composition measurements and blood sampling 3 days before, and 3 and 6 months after STN DBS. Peripheral concentrations of ghrelin, NPY, and leptin were determined, as well as the L-dopa equivalent daily dose. Patients were clinically evaluated using the Unified Parkinson's Disease Rating Scale. RESULTS: Three months after surgery, a significant WG was observed (3.09 ± 5.00 kg; p = 0.007) with no further increase at 6 months. Three months postoperatively, NPY circulating levels increased significantly (p = 0.05), while the increase of ghrelin levels reached statistical significance at 6 months (p = 0.001). WG was significantly associated with changes of ghrelin and leptin levels at 3 and 6 months, respectively. CONCLUSIONS: STN DBS seems to temporarily dysregulate the hypothalamic secretion of NPY and ghrelin. The variation of weight may be attributed to an increased production of ghrelin and leptin. A possible neuroprotective role of DBS, exerted through the increase of ghrelin levels, should be further studied.

Motor unit number estimation and quantitative needle electromyography in stroke patients.

OBJECTIVE: To evaluate the effect of upper motor neuron damage upon motor units' function by means of two separate and supplementary electrophysiological methods. METHODS: The abductor digiti minimi muscle of the non-paretic and the paretic side was studied in forty-six stroke patients with (a) motor unit number estimation (MUNE) - adapted multiple point stimulation method and (b) computerized quantitative needle electromyography (EMG) assessing the configuration of voluntary recruited motor unit potentials. Main outcome comparisons were focused on differences between non-paretic and paretic side. RESULTS: On the affected hands mean MUNE value was significantly lower and mean area of the surface recorded single motor unit potentials was significantly larger than the corresponding ones on the non-paretic hands. EMG findings did not reveal remarkable differences between the two sides. Neither severity nor chronicity of stroke was related to MUNE or EMG parameters. DISCUSSION: MUNE results, which suggested reduced motor unit numbers in stroke patients, in conjunction with the normal EMG features in these same muscles has given rise to different interpretations. In a clinical setting, reinnervation type changes in the EMG similar to that occurring in neuronopathies or axonal neuropathies should not be expected in muscles with central neurogenic lesion.

Effects of subthalamic nucleus deep brain stimulation on sweating function in Parkinson's disease.

PURPOSE: To assess the impact of subthalamic nucleus (STN) deep brain stimulation (DBS) on the sweating function in patients with advanced Parkinson's disease (PD). METHODS: Nineteen patients with idiopathic PD (mean age+/-SD, 61.58+/-9.47) were examined immediately before and 6 months after DBS. Each examination session included registration of autonomic symptoms by means of a semi-structural questionnaire and recording of sympathetic skin response (SSR) from both palms and one sole. The neurophysiological measurements were compared to those of 19 matched for sex and age healthy controls. RESULTS: Six months post-DBS motor improvement was amounted to 65.9% and the daily levodopa equivalent dose was decreased by 36.4%. Post-operatively, dyshidrosis manifestations were reduced by 66.7% (pre-DBS sudomotor dysfunction in 47.4% of patients and sudomotor fluctuation in 57.1% of the above patients). There were no significant differences in-between pre- and post-DBS results of SSR study. However, the number of patients with at least one abnormal SSR pre-operative was reduced from 6 to 3 post-operative. No correlation was found between this neurophysiological finding and the change of clinical symptoms of hyperhidrosis or the DBS motor improvement. CONCLUSIONS: These results, although based on a small sample, suggest that STN DBS, in addition to the effect to the mobility, might also favorably regulate sweat in idiopathic PD.

Interictal alterations of cardiovagal function in chronic epilepsy.

AIM: To assess the function of parasympathetic heart control in patients with epilepsy by means of clinical routine neurophysiology. MATERIALS AND METHODS: Seventy-one consecutive epileptic patients (mean age+/-S.D. 37.8+/-12.9 years) with partial or generalized seizures manifested for more than 6 months and receiving various therapeutic regimes and 71 matched for sex and age healthy controls undertook a battery of neurophysiological tests which consisted of sensory conduction of sural nerve; R-R interval variation during normal and deep breathing; Valsalva manoeuvre and tilt test for calculation heart rate changes to respiratory strain and standing. RESULTS: The patient group showed a significant difference in all parasympathetic parameters studied compared to the control group. Overall, 42.2% of patients had abnormal measurement in at least one of the parameters and Valsalva was the most frequently abnormal one (31% of patients). Sural nerve amplitude was significantly lower in the patients than in the controls and its measurements were associated with those of the tilt test. Long epilepsy duration (more than 10 years) and treatment with phenytoin showed a negative effect on data of R-R interval variation during deep breathing. No other correlations between measurements of parasympathetic parameters and epilepsy related characteristics i.e. type and frequency of seizure, monotherapy or combined therapy with seven other antiepileptic medications, were proven. CONCLUSIONS: Our results suggested that simple neurophysiological tests, suitable for screening purposes were able to demonstrate suppressed cardiovagal control in epileptic patients and to identify those in need for further analysis of cardiovagal function.

Evaluation of conduction properties of somatic and sympathetic sudomotor fibers in patients with epilepsy.

To assess the function of fast somatic nerve fibers and sympathetic sudomotor system in patients with partial or generalized seizures, receiving various therapeutic regimes. The authors studied 60 patients (mean age 36.7 +/- 12.5 years) and 60 matched healthy controls by clinical, conventional nerve conduction study, and sympathetic skin responses (SSR) from hand and foot. Compared with controls, patients showed a tendency, occasional reaching significant level, to conduction slowing and amplitude reduction in the sensory and less often in the motor nerve study. Clinical signs of neuropathy were disclosed in 8.3% of patients, whereas at least one abnormal sensory parameter was evident in 18.3%. Mean SSR latencies in the patients were significantly prolonged. At least one SSR abnormality was shown in 20 (33.3%) patients; six of these had absent SSR from the hand or/and the foot. Polytherapy (vs. monotherapy) and topiramate, but not any other particular drug, seemed to have a negative effect on SSR measurements. The results suggested that despite the insignificant clinical manifestations of neuropathy, an electrophysiological examination was able to demonstrate some subclinical abnormalities of the fast somatic fibers in the peripheral nerves and of the sympathetic sudomotor function in a considerable number of epileptic patients.