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Biomedical subjects

J Vesper

Publications and source records attributed to J Vesper.

At least 19 recordsLinked to original sources
PubMed2005

[Hypothalamic deep brain stimulation in patients with chronic cluster headaches. Suggestions for patient selection].

Cluster headaches involve a stereotypic symptomatic and belong to the most severe primary pain syndromes. Imaging studies have demonstrated functional and structural changes in the inferior-posterior hypothalamus ipsilateral to the pain. These changes are highly specific to the syndrome, strongly suggesting that this anatomical region is the trigger or generator of the acute attacks and/or determine the duration of the acute pain. These findings have led to the successful therapy of 19 not or difficult to treat patients with hypothalamic deep brain stimulation, resulting in long-term periods without pain and without significant side effects. Recently, however, a patient was reported who died after the operation due to increased blood pressure leading to the rupture of a previously non-diagnosed aneurysm. This article offers a translated summary of the recently published criteria of an international consensus group, which, in addition to a positive ethics vote, should be fulfilled before such deep brain stimulation of the hypothalamus is carried out in such patients.

Cluster Headache↗
PubMed2004

Long-term suppression of extrapyramidal motor symptoms with deep brain stimulation (DBS).

Deep Brain Stimulation (DBS) was investigated for the treatment of extrapyramidal motor symptoms. Both tremor and rigidity as well as akinesia are known to be permanently suppressed by applying a high-frequency current to different basal ganglia nuclei. Chronic DBS was performed in 113 patients using stereotactically implanted quadripolar electrodes in the ventrolateral thalamus (n = 43), the globus pallidus internus (n = 15), or the subthalamic nucleus (n = 55). Subcutaneous implantation of the generator occurred during a second procedure following correct positioning of the electrodes and confirmation of effectiveness by external stimulation. Patients were followed up using standardized rating scales before and after surgery. Deep Brain Stimulation significantly suppresses extrapyramidal symptoms such as tremor (p < 0.001), rigidity (p < 0.001), dyskinesia (p < 0.01), akinesia, and dystonia (p < 0.05). Permanent side effects were avoided by changing the stimulation parameters. Severe complications occurred in only two patients (n = 2, 1.8 %). DBS is a safe and effective long-term treatment for tremor, rigidity, dyskinesia, akinesia and dystonia.

Adult↗
PubMed2003

Differential modulation of subcortical target and cortex during deep brain stimulation.

The combination of electrical deep brain stimulation (DBS) with functional imaging offers a unique model for tracing brain circuitry and for testing the modulatory potential of electrical stimulation on a neuronal network in vivo. We therefore applied parametric positron emission tomography (PET) analyses that allow characterization of rCBF responses as linear and nonlinear functions of the experimentally modulated stimulus (variable stimulator setting). In patients with electrodes in the thalamic ventrointermediate nucleus (VIM) for the treatment of essential tremor (ET) here we show that variations in voltage and frequency of thalamic stimulation have differential effects in a thalamo-cortical circuitry. Increasing stimulation amplitude was associated with a linear raise in rCBF at the thalamic stimulation site, but with a nonlinear rCBF response in the primary sensorimotor cortex (M1/S1). The reverse pattern in rCBF changes was observed with increasing stimulation frequency. These results indicate close connectivity between the stimulated nucleus (VIM) and primary sensorimotor cortex. Likewise, stimulation parameter-specific modulation occurs at this simple interface between an electrical and a cerebral system and suggests that the scope of DBS extends beyond an ablation-like on-off effect: DBS could rather allow a gradual tuning of activity within a neuronal circuit.

Aged↗
PubMed2003

Identification of target areas for deep brain stimulation in human basal ganglia substructures based on median nerve sensory evoked potential criteria.

OBJECTIVE: In the interventional treatment of movement disorders, the thalamic ventral intermediate nucleus (VIM) and the subthalamic nucleus (STN) are the most relevant electrode targets for deep brain stimulation (DBS). This study tested the value of somatosensory evoked potentials (SEP) for the functional identification of VIM and STN. METHODS: Median nerve SEP were recorded from the final stimulation electrodes targeted at STN and VIM. Throughout the stereotactic procedure SEP were recorded during short electrode stops above STN/VIM and within the presumed target areas. After digital filtering, high and low frequency SEP components were analysed separately to parameterise both the 1000 Hz SEP burst and low frequency (<100 Hz) components. RESULTS: SEP recorded in the VIM target region could unequivocally be distinguished from SEP recorded in STN. The 1000 Hz burst signal was significantly larger in VIM than in STN without any overlap of amplitude values. In the low frequency band, a primary high amplitude negativity was obtained in VIM, contrasting with a low amplitude positivity in STN. SEP waveshapes in recordings above target positions resembled SEP obtained in STN. When entering VIM, a sharp amplitude increase was observed over a few millimetres only. CONCLUSIONS: Based on SEP criteria, the VIM target but not the STN region can be identified by typical SEP configuration changes, when penetrating the target zone. The approach is independent of the patient's cooperation and vigilance and therefore feasible in general anaesthesia. It provides an easy, reliable, and robust tool for the final assessment of electrode positions at the last instance during electrode implantation when eventual electrode revisions can easily be performed.

Adult↗
PubMed2002

Deep brain stimulation of the globus pallidus internus (GPI) for torsion dystonia--a report of two cases.

Generalized dystonia is known as a type of movement disorder in which pharmacotherapeutic options are very limited. Deep Brain Stimulation (DBS) is well established for Parkinson's disease (PD) and tremor dominant movement disorders. We report on two cases of generalized dystonia which were successfully treated by chronic high frequency stimulation in the Globus pallidus internus (GPI). Two 26 and 27 years old males suffered from severe torsion dystonia and multisegmental dystonia of the lower limbs. Case 1 is a familiar type of dystonia (DYT1 positive). The onset of symptoms in both cases was at age 7. The complaints were initially treated with orally administered benzodiazepines, anticholinergic drugs, later by baclofen and L-DOPA. However there was no response. Case 2 was a patient with a history of left side dominated dystonia since the age of 8. It was first diagnosed as a psychogenic movement disorder. Prior to surgery he was treated with L-DOPA, anticholinergics, Baclofen without any effect. There was only a limited effect on high doses of diazepam. The patient is DYT1 negative. The target point was on both sides the GPI. Intraoperative computerized tomography (CT) and ventriculography (VG) were used for target setting. Furthermore microrecordings were helpful to ensure the exact electrode position. Surgery was performed under analgosedation. Two weeks after surgery we first observed a relief of symptoms in both cases. A significant reduction in the Burke-Fahn-Marsden-Dystonia Movement Rating Scale was observed at the 6 month follow-up (case 1: 95%, case 2: 80%). In case 1 a slight dystonic movement of the left ankle was the only remaining symptom under stimulation. The medication was continuously reduced. At the 24 month follow-up the effect of stimulation remained unchanged. However high stimulation parameters are required to maintain an optimal effect (mean 3.5 V, 400 microseconds, 145 Hz).

Adult↗
PubMed2002

Results of chronic subthalamic nucleus stimulation for Parkinson's disease: a 1-year follow-up study.

BACKGROUND: Deep brain stimulation (DBS) has been established as an alternative approach for the treatment of advanced Parkinson's disease (PD). Recently, the subthalamic nucleus (STN) has been identified as the optimal target for DBS. METHODS: Thirty-eight patients have undergone surgery for advanced PD since 1996. They include 12 females and 26 males with a mean age of 55.6 years. The mean stage on the Hoehn and Yahr Scale was 3.5 (off condition). Electrodes (Medtronic DBS 31389) were stereotactically implanted into the STN bilaterally. Targeting was performed using computerized tomography (CT) scans and ventriculography (VG). After 4 days of external stimulation, permanent neurostimulators were implanted. Patients were evaluated preoperatively and 1, 6, and 12 months postoperatively. Evaluations were performed in defined on and off states using the Unified Parkinson's Disease Rating Scale (UPDRS) as well as the Hoehn and Yahr Scale, the dyskinesia scale, and the Activities of Daily Living (ADL) Scale. RESULTS: Significant improvement of all motor symptoms was found in all patients (UPDRS motor score 32/48 preoperatively versus 15/30 at 12-month follow-up, p < 0.001). Daily off-times were reduced by 35%. Dyskinesias also improved markedly (UPDRS IV: 3.2/3.1 [on/off] vs. 0.9/1.3 at 12 months follow-up). Postoperative L-dopa medication was adjusted (mean reduction: 53%). Complications occurred in two patients (5%) who developed infections, leading to system removal. Systems were replaced after 6 months. Two patients (5%) had a permanent worsening of a previously known depressive state and developed progressive dementia. CONCLUSIONS: TN stimulation is a relatively safe procedure for treating advanced PD. The possibility of readjusting the stimulation parameters postoperatively improves the therapeutic outcome and reduces side effects in comparison to ablative methods.

Electric Stimulation Therapy↗
PubMed2002

[Chronic high frequency deep brain stimulation of the globus pallidus internus for torsion dystonia].

Deep Brain Stimulation (DBS, chronic high frequency stimulation) is well established for Parkinson's disease and tremordominant movement disorders. Generalized dystonia is known as a type of movement disorder in which therapeutic options are very limited. A case of generalized dystonia is reported which was successfully treated by DBS in the Globus pallidus internus (GPI). A 26 years old male suffered from severe torsion dystonia of the lower limbs. The onset of symptoms was at age 7. It started with dystonia of the left foot. He very fast developed severe dystonia of the lower limbs. These complaints were initially treated by diazepam, later by baclofen (Lioresal ((R))) p.o em leader There was no L-DOPA response. Because of the rapid progression of the disease a cervical spinal cord stimulator was implanted with a transient success. Due to further progression of the disease the patient became wheelchair bounded and resistant for oral medication. Limited improvement of symptoms was achieved using continuous intrathecal administration of baclofen. Finally the patient was treated with 980 microgram intrathecal Baclofen (Lioresal ((R))) daily and up to 100 mg diazepam. Under these conditions the patient remained wheelchair bounded with severe lower limb dystonia. As an ultima ratio it was decided to treat the patient with stereotactic implantation of two electrodes (Medtronic 3387) and two neurostimulators (Medtronic ITREL ((R))II). The GPI was the bilateral target point. Intraoperative computerized tomography and ventriculography were used for target setting. Furthermore microrecordings were helpful to ensure the exact electrode positioning. Surgery was performed under sedation. Two weeks after surgery first improvement of symptoms was observed. Patient was able to stand with assistance. At the three months follow-up he could walk without assistance. Slight dystonic movement of the left ankle was the only remaining symptom under stimulation. The oral medication has been continuously reduced. After 6 months it was stopped. The intrathecal administered baclofen was diminished to 250 microgram daily. At the 24 months follow-up the effect of stimulation remained unchanged. However high stimulation parameters are required to maintain an optimal effect (3,5 V, 400 microseconds 145 Hz for both sides). Deep Brain Stimulation of the Globus Pallidus internus is an alternative approach for severe cases of generalized dystonia.

Adult↗
PubMed2002

Dual channel deep brain stimulation system (Kinetra) for Parkinson's disease and essential tremor: a prospective multicentre open label clinical study.

OBJECTIVES: To evaluate the safety and efficacy of a new dual channel stimulator (Kinetra) in patients with severe Parkinson's disease (PD) or essential tremor (ET). METHODS: 111 patients with PD and 18 with ET were studied. Leads were implanted into the subthalamic nucleus (STN) or internal globus pallidus of patients with the akinetic/rigid type of PD. Leads were implanted into the ventral intermediate nucleus (VIM) of the thalamus or the STN in patients with the tremor dominant type of PD and in those with ET. Technical data on the device and adverse events occurring during the study were documented. Patients were assessed with established and validated clinical scales before surgery and at three and six months' follow up. RESULTS: No device failure or unexpected adverse events occurred during the study. The dual channel stimulator used in stimulation of the STN, internal globus pallidus, and VIM in PD and ET was as safe and effective as the single channel stimulators in use. Mortality, morbidity, and infections were documented in the 129 treated patients. The parameter settings were similar to those usually programmed with single channel stimulators. Time spent in the operating room to implant the Kinetra system was systematically documented. In the PD group, improvement in the unified Parkinson's disease rating scale motor score, decrease in medication OFF periods, and reduced levodopa induced dyskinesia by bilateral STN stimulation were similar to those previously reported with bilaterally applied single channel stimulators. In the ET group upper and lower limb tremor scores were reduced by VIM stimulation. Activities of daily living improved in both disease groups. CONCLUSION: The Kinetra facilitated bilateral deep brain stimulation implantation surgery and is easy to use. It offers more advantages for the patient than the single channel stimulators; consequently, this new device may be recommended to treat patients with severe PD and ET.

Brain↗
PubMed2001

[Neurosurgical therapy of Parkinson disease. Deep brain stimulation].

The introduction of continuous high frequency stimulation (deep brain stimulation) into functional neurosurgery has opened up new avenues in the treatment of Parkinson's disease. This new technique expands the therapeutic possibilities available to those patients in whom, over the years, the effectiveness of drug treatment has deteriorated, or severe side effects developed. In the individual case, the decision as to whether to operate is taken on the basis of interdisciplinary cooperation between the care-providing neurologist and the neurosurgeon specialized in this particular field.

Basal Ganglia↗
PubMed2000

Propofol narcosis dissociates human intrathalamic and cortical high-frequency (> 400 hz) SEP components.

Human somatosensory evoked potentials (SEP) contain a brief burst of high-frequency wavelets (>400 Hz) presumably reflecting rapidly repeated population spikes of as-yet undetermined origin. To study state-dependent response changes, SEP after electric median nerve stimulation were recorded in six Parkinson's disease patients perioperatively from intrathalamic electrode implants, and in five non-implanted patients from scalp electrodes, before and under propofol narcosis. In all intrathalamic recordings burst amplitude and intraburst frequency (approximately 950 Hz) proved to be almost stable under propofol administration. In strong contrast, the scalp burst (640 Hz) was significantly slowed (480 Hz) under propofol narcosis, and its amplitude reduced to 28% of the pre-propofol baseline. Low-frequency SEP components which underly the burst at thalamic (P16) and cortical level (N20) did not change significantly. This dissociation of bursts indicates neuronal generators showing different sensitivities to propofol narcosis, with a robust thalamic response and a state-dependent cortical contribution, possibly from pyramidal chattering cells and/or inhibitory interneurons.

Action Potentials↗
PubMed2000

Double-pulse stimulation dissociates intrathalamic and cortical high-frequency (>400Hz) SEP components in man.

Human somatosensory evoked potentials (SEP) contain high-frequency (600 Hz) wavelet bursts possibly reflecting repetitive population spikes in thalamocortical axons and/or postsynaptic responses. To dissociate thalamic and cortical burst components the recovery of intrathalamic SEP (derived from electrodes implanted for movement disorder therapy in seven patients) was compared with scalp SEP in six age-matched Parkinsonian patients and six healthy younger subjects. Upon electric median nerve double-pulse stimulation conditioned scalp bursts were found attenuated in both groups, more for 10ms than 20ms interstimulus intervals; moreover, intraburst frequencies decreased from 690Hz to 590Hz. By contrast, intrathalamic burst amplitudes and frequencies (around 1 kHz) remained largely stable. These dissociations indicate functionally distinct generator mechanisms for scalp and intrathalamic high-frequency SEP bursts.

Action Potentials↗
PubMed2000

Permanent postoperative anosmia: a serious complication of neurovascular decompression in the sitting position.

In posterior fossa surgery, the sitting position offers a number of advantages believed to outweigh complications such as air embolism and pneumatocephalus. For this reason, the sitting position is frequently used in neurovascular decompression for trigeminal neuralgia. Two years ago we reported on a previously undescribed complication: permanent postoperative anosmia. Following the recent occurrence of a second case, we conducted a nationwide survey to determine the frequency of this complication. Permanent postoperative anosmia following surgical procedures in the sitting position has been observed in 3 other institutions. In addition, the survey revealed that only 40% of German neurosurgeons still favor the sitting position for surgery of the posterior cranial fossa. Considering that permanent anosmia severely reduces quality of life, and that it can be avoided by using another position, the sitting position for surgical procedures in the posterior fossa should be restricted to special cases (e.g., brain stem tumors).

Decompression, Surgical↗
PubMed1999

Spatiotemporal characteristics of human intrathalamic high-frequency (>400Hz) SEP components.

Somatosensory evoked potentials (SEP) were recorded in 11 awake patients from intrathalamic electrodes implanted for tremor treatment. A brief (7ms) polyphasic SEP burst (mean frequency > 1000 Hz, with occasional drops to 600 Hz) was found to be superimposed onto the primary thalamic low-frequency response at 16 ms (tP16) and preceeded a scalp-derived 600 Hz burst by 4 ms. Thalamic burst and tP16 generators had a close intrathalamic co-localization. The thalamic burst strength varied more than and independently from tP16. High-frequency thalamic SEP bursts probably reflect a superposition of slightly asynchronously triggered population spikes, generated e.g. by bursting thalamocortical relay cells. The thalamic burst amplitude fluctuations independent from low-frequency responses suggest a peculiar role for thalamic burst coding in awake subjects.

Adult↗
PubMed1997

[Costosternal swelling and diffuse bone pain in tubercular osteomyelitis].

HISTORY AND CLINICAL FINDINGS: For about a year a 28-year-old Nigerian had been suffering from diffuse bone pain, intermittent fever, weight loss and weakness. Physical examination was unremarkable except for a swelling at the sternal angle. INVESTIGATIONS: The tuberculin test was clearly positive and tests for inflammatory disease were elevated, but the chest radiograph was normal. Bone scintigraphy demonstrated multiple sites of increased storage in the ribs and vertebral column. Magnetic resonance imaging revealed a large paravertebral abscess, which was needled under computed tomography monitoring. Polymerase chain reaction of the aspirate demonstrated Mycobacterium tuberculosis. TREATMENT AND COURSE: While initial treatment with combined isoniazid, streptomycin, rifampicin and pyrazinamide, the first two drugs had to be discontinued, the microorganism not being sensitive to them, and were replaced by ethambutol and amikacin. The abscess was drained and the vertebral fracture surgically stabilised. There were no neurological abnormalities and the lesions largely healed. CONCLUSION: Even without pulmonary involvement tuberculosis must be included in the differential diagnosis of rheumatic diseases with joint and vertebral column involvement, such as the SAPHO syndrome and other inflammatory bone diseases.

Abscess↗
PubMed1997

Periradicular therapy in lumbar radicular syndromes: methodology and results.

Periradicular therapy (PRT) has become popular in the treatment of lumbar radicular complaints, both primary, due to disc herniations (Group 1), and postoperative, following disc surgery (Group 2). However, hitherto reported data on 'periradicular injections' are more of a technical nature. The present study was designed to evaluate the therapeutic success of CT- versus fluoroscope-guided periradicular injections of local anaesthetics and corticoids, and to investigate the impact of imaging procedures on the results. We report on 80 patients who underwent CT-guided (n = 40) or fluoroscope-guided (n = 40) PRT for lumbar radicular irritation since April 1993. Forty patients had primary nerve root irritation due to disc protrusion, and 40 suffered from postoperative epidural fibrosis. Follow-up consisted in a clinical examination and an interview one day after each injection as well as 1 and 6 months later. Assessment was based on a score taking into account the clinical findings, the patient's complaints, and the patient's evaluation. Six months following treatment there was a significant reduction of ischialgia in both Groups 1 and 2 (p < 0.001). However, the results were significantly poorer in Group 2 (postoperative). Among the patients not operated on, those who underwent CT-guided injections had a significantly better outcome (p < 0.001). PRT had no significant influence on low back pain or pseudoradicular syndromes. The improvement of sensory disturbances achieved by both CT- and fluoroscope-guided injections in patients not previously submitted to surgery is statistically significant (p < 0.05). As compared to Group 1 (no surgery), the positive effects in patients of Group 2 were of significantly shorter duration (p < 0.05). Motor deficits were not influenced by the treatment. Long-term follow-up shows that there is no positive effect in those patients in whom the first two PRT attempts had failed. Thus, PRT represents a useful long-term therapeutic alternative for lumbar radicular syndromes, particularly when due to primary discogenic compression. CT-guided injection is superior to fluoroscope-assisted treatment for both its visualization and its longer-lasting effect.

Adult↗
PubMed1995

Intrastriatal dopamine infusion reverses compensatory increases in D2-dopamine receptors in the 6-OHDA lesioned rat.

Direct infusion of dopamine into the corpus striatum has been proposed as a potential approach for the treatment of Parkinson's disease. The present study examined the effect of intrastriatal dopamine infusion on D2-dopamine receptors in the 6-hydroxydopamine (6-OHDA) lesioned rat brain. The completeness of the 6-OHDA-induced nigrostriatal injury was confirmed using [3H]-mazindol autoradiography and apomorphine-induced behaviour. Intrastriatal infusion of three different dopamine doses significantly reduced the apomorphine-induced behaviour. [3H]-spiperone autoradiography performed one day after the termination of dopamine infusion into the striatum revealed a dramatic reduction of D2-dopamine receptor binding. The mean +/- SEM percent reduction of D2 receptor binding in the affected areas of the striatum was 28.8 +/- 1.0% for 4.74 micrograms dopamine/h infusion rate, 35.0 +/- 1.6% for 9.48 micrograms dopamine/h infusion rate and 33.3 +/- 5.0% for 14.22 micrograms dopamine/h infusion rate when compared to the unlesioned side. Infusion of vehicle alone did not have any effect. The present results support the concept that intrastriatal dopamine infusion may be a useful therapeutic approach for the treatment of Parkinson's disease.

Animals↗
PubMed1994

Multicenter double-blind study examining the antidepressant effectiveness of the hypericum extract LI 160.

Seventy-two depressive patients of 11 physicians' practices were treated in a double-blind study for a period of 6 weeks either with hypericum extract LI 160 or with placebo. Inclusion criterion was a major depression in accordance with DSM-III-R. The changes were assessed using four psychometric scales (HAMD, D-S, BEB, CGI). After 4 weeks of therapy, the statistical evaluation revealed a significant improvement in all four psychometric tests in the active group as compared to the placebo group. After switching the placebo group to active treatment (5th to 6th week of therapy), significant improvements were found in the original placebo group. No serious side effects were observed.

Adolescent↗