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Biomedical subjects

Jacques Caemaert

Publications and source records attributed to Jacques Caemaert.

12 recordsLinked to original sources
PubMed2005

Comparison of postural control in unilateral stance between healthy controls and lumbar discectomy patients with and without pain.

MAIN PROBLEM: Previous studies have demonstrated that sciatica patients have poorer postural control than healthy controls and that postural control remains unchanged 3 months after lumbar discectomy in sciatica patients. The aims of the current study were to investigate whether static balance control recovers in pain-free discectomy patients long-term after lumbar discectomy. Next is to determine whether static balance responses of asymptomatic and symptomatic lumbar discectomy patients differed from each other and from healthy controls. In addition, the influence of the extent of disc resection (unilateral/bilateral removal) and the side of operation on static balance control were investigated. METHODS: Fifteen pain-free lumbar discectomy patients, 23 lumbar discectomy patients with residual pain and 72 controls performed unilateral stance tasks with eyes open and eyes closed on a force plate were taken up for the investigation. Three repetitions of a 10 s unilateral stance test were performed on each leg. Postural sway was determined. Patients were divided into three age groups. RESULTS: In the eyes open condition, there was no significant difference between postural sway of pain-free lumbar discectomy patients and controls (P=0.68), whereas balance of patients with pain was significantly worse than in controls (P=0.003). In the eyes closed condition, the sway in both groups of lumbar discectomy patients was significantly worse than in controls (pain-free P=0.009/painful P<0.001). No significant differences were found in postural sway between patients with unilateral and bilateral disc resection. In unilateral stance on the leg of the operated side, centre of gravity sway was not significantly different in the eyes open condition compared to the eyes closed condition, whereas in stance on the leg of the non-operated side, postural sway was significantly lower in the eyes open condition compared to the eyes closed condition. In both conditions, postural sway in the age group of 50-65 years was significantly higher than in the age groups of 30-39 years (eyes open P=0.005; eyes closed P<0.001) and 40-49 years (eyes open P=0.002; eyes closed P=0.006). There was no significant difference between the age group of 30-39 years and the age group of 40-49 years (P=0.51). CONCLUSION: As for long-term following lumbar discectomy, there is no complete recovery of postural control. Patients seem to develop visual compensation mechanisms for underlying sensory-motor deficits, which are, however, sufficient in case of pain relief only. Further study is needed to determine the cause of the balance disturbances in lumbar discectomy patients.

Adult↗
PubMed2005

Long-term effects of bilateral subthalamic nucleus stimulation in advanced Parkinson disease: a four year follow-up study.

In this study we aimed to investigate the effects of bilateral STN HFS in patients with advanced Parkinson disease (PD) at long-term, with a minimum follow-up of 4 years. Twenty patients (15 men, five women) were included, with a mean age of 60.9+/-8.1 years. Surgery was performed under local anesthesia. The target was defined on computerized tomography (CT). At 3 months, significant improvements were found on the total Unified Parkinson disease rating scale (UPDRS) III (motor) score, in the medication. off (from 42.3+/-9.3 to 19.5+/-6.4), as well as the medication on (from 18.6+/-12.1 to 10.1+/-5.9) phase. The UPDRS IVa (dyskinesias) and IVb (motor fluctuations) scores decreased significantly. At long-term follow-up, there were still significant improvements on the total UPDRS III motor score (from 42.3+/-9.3 to 24.2+/-13.2), as well as in all motor subscores, in the off phase, during stimulation. In the on phase, the only significant improvement was seen for rigidity. Complications included hypomania to mania in four patients. Our results indicate that HFS STN results in long-lasting improvement of the motor symptoms, ADL activities and functional performance in patients suffering from advanced PD. The stimulation induced behavioural changes need special consideration.

Activities of Daily Living↗
PubMed2003

Unicoronal suture autotransplantation in the rabbit.

INTRODUCTION: Our hypothesis was that a neurocranial suture autograft will, when shielded from dura, grow and be incorporated into the calvarium. METHODS: Growth was monitored by marker separation in three isohistogenic groups of rabbits, between postnatal days 9 and 90. In order to simulate increased neurocapsular expansion force, the left-sided coronal suture of a group of 20 rabbits was immobilised with a resorbable suture on gestational day 25. The other group of 10 rabbits was sham-operated. On postnatal day 9, 10 of the experimental rabbits underwent transplantation of the suture contralateral to the defect resulting from extirpation of the immobilised suture. The transplant was shielded from dural influence by a platinum foil. RESULTS: The growth of the immobilised coronal sutures was severely impaired, and also that of the contralateral unicoronal sutures to a lesser extent. A significant catch-up of growth occurred in the transplanted unicoronal sutures. Overgrowth occurred at the donor sites. CONCLUSION: The results allow us to consider suture transplantation combined with endosteal dura stripping in craniosynostosis surgery.

Animals↗
PubMed2003

Lateralized effects of subthalamic nucleus stimulation on different aspects of speech in Parkinson's disease.

In this report, we have analyzed the effects of left and right STN stimulation separately on different aspects of speech. Significant differences were found between left and right stimulation. It appears that selective left-sided stimulation has a profoundly negative effect on prosody, articulation and hence intelligibility. Right-sided stimulation does not display this side-effect. There is no significant difference in speech characteristics between bilateral stimulation on and off. We suggest that a balanced tuning of bilateral basal ganglia networks is necessary for speech, and that the left circuit is probably dominant.

Adult↗
PubMed2003

Neurostimulation for refractory epilepsy.

Neurostimulation is an emerging treatment for refractory epilepsy. To date the precise mechanism of action remains to be elucidated. Better insight in the mechanism of action may identify seizure types or syndromes that respond to such a treatment and may guide the search for optimal stimulation parameters and finally improve clinical efficacy. In the past ten years some progress has been made through neurophysiological, neuroanatomical, neurochemical and cerebral blood flow studies in patients and animals undergoing vagus nerve stimulation (VNS). Interesting results have been found in VNS-treated patients that underwent evoked potential measurements, cerebrospinal fluid investigation, neuropsychological testing and PET, SPECT and fMRI testing. Desynchronisation of abnormal synchronous epileptic activity is one of the hypotheses on the mode of action that might primarily be responsible for an anti-seizure effect. There is however increasing evidence from research and clinical observation that VNS might establish a true and long-term anti-epileptic effect. It has been shown that VNS influences neurotransmission in the brain and provokes long-term changes in cerebral blood flow in areas crucial for epileptogenesis such as the thalamus and medial temporal lobe structures. Deep brain stimulation (DBS) for epilepsy has regained interest. Central nervous system structures known to play a key role in the epileptogenic network such as the thalamus and subthalamic nucleus have been targeted. Another approach is to target the ictal onset zone such as the medial temporal lobe. At Ghent University Hospital 10 patients have been treated with long-term amygdalohippocampal DBS. Several hypotheses have been raised for the mechanism of action of DBS for refractory seizures. Seizure reduction may be due to a microlesion caused by electrode insertion or by provoking a reversible functional lesion due to the effect of electrical current on hyperexcitable tissue. Neurophysiological techniques such as evoked potentials monitoring and intraoperative single unit potential recordings may guide correct electrode placement, individual DBS titration and elucidation of the mechanims of action of DBS for epilepsy.

Animals↗
PubMed2002

Long-term amygdalohippocampal stimulation for refractory temporal lobe epilepsy.

Short-term deep brain stimulation (DBS) recently has been shown to be efficacious in refractory temporal lobe epilepsy. We (1) evaluated long-term DBS in medial temporal lobe structures in patients with normal magnetic resonance imaging (MRI) findings and (2) investigated the use of chronic DBS electrodes for the localization of the ictal onset zone before DBS. In three patients with complex partial seizures (CPSs), DBS electrodes were implanted in the amygdalohippocampal region to identify and subsequently stimulate the ictal onset zone. CPSs were compared before and after chronic DBS. Side effects were carefully monitored. DBS electrodes yielded high-quality electroencephalogram recordings showing unilateral seizure onset in medial temporal lobe structures. For all patients, unilateral amygdalohippocampal stimulation was performed. After a mean follow-up of 5 months (range, 3-6 months), all patients had a greater than 50% reduction in seizure frequency. In two patients, antiepileptic drugs could be tapered. None of the patients reported side effects. This open study demonstrates the feasibility of consecutive electroencephalographic recordings and DBS in medial temporal lobe structures using DBS electrodes. These results prompt further studies in a larger patient population to establish the efficacy and safety of chronic DBS as an alternative treatment for refractory temporal lobe epilepsy.

Adult↗
PubMed2002

Ictal source localization in presurgical patients with refractory epilepsy.

Source localization of epileptic foci using ictal spatiotemporal dipole modeling (ISDM) yields reliable anatomic information in presurgical candidates. It requires substantial resources from EEG and neuroimaging laboratories. The profile and number of patients who may benefit from it are currently unknown. The purpose of this study is to demonstrate the clinical usefulness of source localization in a prospectively analyzed series. One hundred patients (51 male and 49 female patients) with mean age of 31 years (range, 2 to 63 years) and mean duration of refractory epilepsy of 20 years (range, 1 to 49 years) were enrolled consecutively in a presurgical protocol. Ictal EEG was available in 93 patients. ISDM was performed when suitable ictal EEG files were available. The clinical applicability of ISDM was examined in three patients groups: 37 patients in whom ictal EEG recording and MRI were congruent (group I), 30 patients in whom results were not completely congruent but not incongruent (group II), and 26 patients in whom the results were incongruent (group III). ISDM could be performed in 31 of 100 patients: 11 in group I, 8 in group II, and 12 in group III. ISDM influenced decision making in none of the patients in group I, in 4 of 8 patients in group II, and in 10 of 12 patients in group III. Typically, the results of ISDM directed avoiding intracranial EEG recordings in what appeared to be unsuitable candidates for resection by clearly confirming the incongruency between ictal EEG and MRI findings. In this series of 100 presurgical candidates, ictal source localization could be performed in 31% of patients. In 14% of patients, it proved to be a key element in the surgical decision process.

Adolescent↗
PubMed2002

Vagus nerve stimulation for refractory epilepsy.

Vagus nerve stimulation (VNS) is a neurophysiological treatment for patients with medically or surgically refractory epilepsy. Since the first human implant in 1989, more than 10,000 patients have been treated with VNS. Two randomized controlled studies have shown a statistically significant decrease in seizure frequency during a 12-week treatment period versus a baseline period when 'high stimulation' mode was compared with 'low stimulation' mode. The efficacy appears to increase over time. In general, one third of the patients show a > 50% reduction of seizure frequency; one third show a 30-50% seizure reduction, and one third of patients show no response. Few patients become seizure-free. Side effects during stimulation are mainly voice alteration, coughing, throat paraesthesia and discomfort. When studied on a long-term basis, VNS is an efficacious, safe and cost-effective treatment not only in adults but also in children and the elderly. The precise mechanism of action remains to be elucidated. In recent years much progress has been made through neurophysiological, neuroanatomical, neurochemical and cerebral blood flow studies in animals and patients treated with VNS. Further elucidation of the mechanism of action of VNS may increase its clinical efficacy and our general understanding of some physiopathological aspects of epilepsy. Finally, VNS may become an alternative treatment for other conditions such as depression and pain.

Clinical Trials as Topic↗
PubMedDate not supplied

Vagus nerve stimulation for refractory epilepsy: a transatlantic experience.

Vagus nerve stimulation (VNS) is an alternative treatment for medically or surgically refractory epilepsy. The long-term efficacy and safety of VNS were evaluated in a large patient series at Ghent University Hospital and Dartmouth-Hitchcock Medical Center. Between March 1995 and February 2003, seizure frequency and type as well as prescribed antiepileptic drugs and side effects were prospectively assessed in 131 patients treated with VNS in either center. Patients with a minimum follow-up duration of 6 months were included in the efficacy and safety analysis. A total of 118 of 131 implanted patients had a minimum postimplantation follow-up period of 6 months (mean, 33 months). The mean age of these patients was 32 years and the mean duration of refractory epilepsy was 22 years. The mean reduction in monthly seizure frequency in all patients was 55% (range, 0-100; SD = 31.6). Seven percent of patients were free of seizures with impaired consciousness, 50% of patients had a seizure frequency reduction of more than 50%, and 21% of patients were nonresponders. Fifteen patients reported stimulation-related side effects such as hoarseness or gagging. In a large patient series from two geographically distinct epilepsy centers located in two different continents, VNS proved to be efficacious and safe during long-term follow-up.

Adolescent↗
PubMedDate not supplied

Suboccipital craniectomy, dorsal laminectomy of C1, durotomy and dural graft placement as a treatment for syringohydromyelia with cerebellar tonsil herniation in Cavalier King Charles spaniels.

OBJECTIVE: To evaluate retrospectively the efficacy of the suboccipital craniectomy and dorsal laminectomy of C1 with durotomy and placement of a dural graft for treatment of syringohydromyelia (SHM) because of cerebellar tonsil herniation in Cavalier King Charles spaniels (CKCS). This technique is used with great success in human medicine. STUDY DESIGN: Four CKCS diagnosed by Magnetic resonance imaging (MRI) of SHM because of cerebellar tonsil herniation and not responsive to medical therapy underwent a suboccipital craniectomy and dorsal laminectomy of C1 (2 dogs) and of C1 and partial C2 (2 dogs) with durotomy and placement of a dural graft. Three dogs were evaluated neurologically 24 hours, 1 month, and 3 months postoperatively and evaluations were compared with preoperative neurological examination. Repeat MRI took place 3 months postoperatively. RESULTS: Neurological examinations showed neither improvement nor progression of clinical signs 3 months postoperatively. MRI showed no regression of syrinx size 3 months postoperatively. CONCLUSION: Improvement was not seen. Given the progressive nature of the disorder, evaluation over a longer period of time is necessary to detect if progression has stopped. Some modification to the surgical technique is needed to accomplish the same results as in human medicine. A study of a larger population is needed to attain more reliable information. CLINICAL RELEVANCE: Suboccipital craniectomy and dorsal laminectomy of C1 with durotomy and placement of a dural graft is a feasible technique in CKCS, but needs some modification to accomplish the same results as in human medicine.

Animals↗
PubMedDate not supplied

Primary resected meningiomas: relapses and proliferation markers.

UNLABELLED: Relapses of meningiomas are a well known phenomenon during follow-up. The significance of sex, age, surgical treatment and mitotic frequency with regard to relapses are still a matter of debate. PATIENTS AND METHODS: The study included 125 meningioma patients who underwent surgical intervention between 1986 and 1997 They were in follow-up for 3, 5, 10 and 15 years; they were grouped as "stable" or "relapsing" tumours. The follow-up was based on magnetic resonance image (MRI) and tomodensitometry (TDM). The labelling index for Ki67 and PCNA (proliferation markers) was scored at resection. Risk factors for relapse were reviewed using univariate analysis and Cox hazards model. RESULTS: One hundred and twenty-five patients were under medical control of whom 26 showed a relapse. Among them 25 arose from subtotal resected tumours and 1 was a recurrence. Relapses comprised 16 females and 10 males. Tumour relapses at 3,5,10 and 15 years were, respectively, 8.8%, 13.6%, 17.6% and 20.8%. Proliferation markers, at group level, were statistically significantly different to distinguish stable from relapsing and malignant from benign meningiomas. Factors significantly associated with tumour relapse in univariate analysis were incomplete resection, histopathology and proliferation markers. In multivariate analysis the proliferation markers and incomplete resection were the only significant risk factors (p<0.05) for relapse. CONCLUSION: To avoid relapses of meningiomas, total resection is recommended. The resection type and proliferation markers are predictive factors for tumour relapse. The proliferation markers cannot be applied at the individual level.

Adolescent↗