Biomedical subjects

D Waldvogel

Publications and source records attributed to D Waldvogel.

15 recordsLinked to original sources

PubMed2007

[Medical treatment of Parkinson's disease].

Our understanding of Parkinson's disease (PD) has evolved. Parkinson's disease is no longer regarded a pure motor disorder, but a complex disease with motor as well as non-motor symptoms, the latter having a major impact on the quality of life of the patient as well as the caregiver. After a few years of suffering from PD, complications of therapy add invariably to the burden of the disease. Many of these complications are not volunteered by the patient or the caregiver, either due to their embarrassing nature or due to lack of insight of their causal relationship with PD or the treatment of PD. However, proper treatment of PD has to address the non-motor symptoms and the complications of therapy as well.

Adult↗

PubMed2004

[Surgical therapy of Parkinson's disease].

For patients with Parkinson's disease with disabling motor fluctuations, dyskinesias or tremor, stereotactic neurosurgery can be a valid therapeutic option. The following lecture will discuss the historical background of stereotactic neurosurgery, possible targets and stereotactic procedures (lesioning vs deep brains stimulation), as well as, the need for a multidisciplinary assessment of a potential candidate.

Dyskinesias↗

PubMed2001

Double-blind randomized trial of buprenorphine and methadone in opiate dependence.

This study compared the safety and efficacy of sublingual buprenorphine tablets with oral methadone in a population of opioid-dependent individuals in a double-blind, randomized, 6-week trial using a flexible dosing procedure. Fifty-eight patients seeking treatment for opioid dependence were recruited in three outpatient facilities and randomly assigned to substitution with buprenorphine or methadone. The retention rate was significantly better in the methadone maintained group (90 vs. 56%; P<0.001). Subjects completing the study in both the treatment groups had similar proportions of opioid positive urine samples (buprenorphine 62%; methadone 59%) and positive urine specimens, as well as mean heroin craving scores decreased significantly over time (P=0.035 and P<0.001). The proportion of cocaine-positive toxicology results did not differ between groups. At week six mean stabilization doses were 10.5 mg per day for the sublingual buprenorphine tablet, and 69.8 mg per day for methadone, respectively. Patient performance during maintenance was similar in both the groups. The high attrition rate in the buprenorphine group during the induction phase might reflect inadequate induction doses. Thus, buprenorphine is a viable alternative for methadone in short-term maintenance treatment for heroin dependence if treatment induction is done with adequate dosages.

Adult↗

PubMed2001

The role of the medial wall and its anatomical variations for bimanual antiphase and in-phase movements.

The medial wall of the frontal cortex is thought to play an important role for bimanual coordination. However, there is uncertainty regarding the exact neuroanatomical regions involved. We compared the activation patterns related to bimanual movements using functional magnetic resonance imaging in 12 healthy right-handed subjects, paying special attention to the anatomical variability of the frontal medial wall. The subjects performed unimanual right and left and bimanual antiphase and in-phase flexion and extension movements of the index finger. Activation of the right supplementary motor area (SMA) proper, right and left caudal cingulate motor area (CMA), and right and left premotor cortices was significantly stronger during bimanual antiphase than bimanual in-phase movements, indicating an important function of these areas with bimanual coordination. A frequent anatomical variation is the presence of the paracingulate sulcus (PCS), which might be an anatomical landmark to determine the location of activated areas. Seven subjects had a bilateral, three a unilateral right, and two a unilateral left PCS. Because the area around the PCS is functionally closer coupled to the CMA than to the SMA, activation found in the area around the PCS should be attributed to the CMA. With anatomical variations such as the presence of a PCS or a vertical branch of the cingulate sulcus, normalization and determination of the activation with the help of stereotaxic coordinates can cause an incorrect shift of CMA activation to the SMA. This might explain some of the discrepancies found in previous studies.

Adult↗

PubMed2000

The variability of serial fMRI data: correlation between a visual and a motor task.

We investigated whether the intersession variability of serial fMRI studies correlates between two activation modalities, i.e. a standardized visual and a standardized motor task. Six volunteers were scanned in at least weekly intervals. The number of pixels activated as well as the activation amplitude varied widely. The maximal difference of the number of pixels activated was 1150%, of the activation amplitude 250%. In three volunteers, the variability was highly correlated between the two tasks. Three other volunteers showed one outlier each. We conclude that the intersession variability is due to global factors affecting the whole brain, but that due to unpredictable outliers, using a standardized task to normalize the data of interest is of limited value.

Adult↗

PubMed2000

The relative metabolic demand of inhibition and excitation.

By using the (14C)2-deoxyglucose method, inhibition has been shown to be a metabolically active process at the level of the synapse. This is supported by recent results from magnetic resonance spectroscopy that related the changes in neuroenergetics occurring with functional activation to neurotransmitter cycling. However, inhibitory synapses are less numerous and strategically better located than excitatory synapses, indicating that inhibition may be more efficient, and therefore less energy-consuming, than excitation. Here we test this hypothesis using event-related functional magnetic resonance imaging in volunteers whose motor cortex was inhibited during the no-go condition of a go/no-go task, as demonstrated by transcranial magnetic stimulation. Unlike excitation, inhibition evoked no measurable change in the blood-oxygenation-level-dependent signal in the motor cortex, indicating that inhibition is less metabolically demanding. Therefore, the 'activation' seen in functional imaging studies probably results from excitation rather than inhibition.

Adult↗

PubMed2000

Mapping the basal ganglia: fMRI evidence for somatotopic representation of face, hand, and foot.

OBJECTIVE: To noninvasively investigate the somatotopy of the basal ganglia in humans. METHODS: Functional MRI, 1.5-T, was performed on six normal right-handed volunteers during simple acoustically paced motor tasks involving the right hand, foot, and face. RESULTS: In a single-subject analysis, statistical parametric maps showed overlapping activation extending along the anteroposterior extent of the left lentiform nucleus (LLN) for the hand, foot, and face representations. Within the LLN, the centers of gravity of each body part, reflecting both the extent and gradient of activation, were all located in the retrocommissural portion of the putamen. Their spatial relationship followed a similar pattern across subjects-face was medial to toes and fingers, toes were dorsal and rostral to fingers. CONCLUSIONS: The somatotopic organization of hand, face, and foot representation in the human lentiform nucleus suggests a triangular pattern, rather than the linear pattern seen in primate studies. The overlap observed between the distinct body parts differs from the cortical sensorimotor representation, indicating a different organizational concept of the basal ganglia.

Adult↗

PubMed1999

Increased iron in the dentate nucleus of patients with Friedrich's ataxia.

Friedreich's ataxia (FA) is the most frequently inherited ataxia. To test the hypothesis that iron is increased in the cerebellum of patients with FA, we developed a multigradient echo magnetic resonance sequence for the three-dimensional imaging of brain iron-induced contrast. Relaxation rate (R2*) values in the unaffected globus pallidus were equal in FA patients and controls, although R2* values in the dentate nucleus of patients were significantly higher, which is most likely due to increased iron.

Adolescent↗

PubMed1999

[Frequency of injection of oral methadone solutions at treatment center for opiate dependence].

A sample of 134 patients (mean age 29.35 years, SD = 5.84, 72.4% of all patients in treatment at this point of time) were interviewed on the injection of peroral methadone. 43% of patients indicated having injected peroral methadone, 21% in the preceding month with a mean frequency of 10.3 injections. All of the patients concerned were in maintenance either with peroral or with injectable methadone. There were no significant differences between males and females and between the maintenance program with peroral and the one with injectable methadone regarding number of persons concerned and frequency of injection. 75% of patients were aware of associated health risks, their knowledge about these risks being modest. Asked about the reason for the injection patients most often mentioned a faster and more intense effect of the injected methadone as well as dependence on the injection per se or the syringe.

Adult↗

PubMed1999

The effect of movement amplitude on activation in functional magnetic resonance imaging studies.

To evaluate the effect of movement amplitude on the "blood oxygen level-dependent effect," the authors studied six normal subjects while they extended their index finger with two different amplitudes. Images were analyzed using SPM96. In five subjects, the signal intensity increase in the primary sensorimotor area was significantly greater with the larger amplitude movement. In other areas of interest (supplementary motor area, premotor cortex, insula, postcentral area, cerebellum), the large-amplitude movement often showed significant activation when the small-amplitude movement did not. The authors conclude that, in studies of the motor system, movement amplitude needs to be controlled.

Adult↗

PubMed1998

Pulsatile tinnitus--a review of 84 patients.

Pulsatile tinnitus can be annoying for a patient and can also be the only clue to a potentially devastating and life-threatening disease. In order to understand its clinical spectrum and management better we analysed the files of 84 patients seen at our institution over a 10-year period. Noninvasive techniques (ultrasound, computed tomography, magnetic resonance imaging) and angiography were employed as investigations tailored to the individual patient. A vascular disorder [i.e. arteriovenous fistula, dissection of the internal carotid artery (ICA), fibromuscular dysplasia, aneurysm of the ICA and sinus thrombosis] was found in 36 patients (42%), most commonly a dural arteriovenous fistula or a carotid-cavernous sinus fistula. In 26 patients with a vascular abnormality, pulsatile tinnitus was the presenting symptom. In 12 patients (14%), nonvascular disorders such as glomus tumour or intracranial hypertension with a variety of causes explained the tinnitus. We conclude that patients with pulsatile tinnitus should be investigated with noninvasive techniques. If these are negative or to clarify abnormal findings of noninvasive techniques selective angiography is needed for diagnosis and to guide treatment.

Adolescent↗

PubMed1998

[Susac syndrome--a case report].

BACKGROUND: The Susac syndrome is often misdiagnosed as Multiple Sclerosis. In the absence of an early diagnosis of the disease, both the doctors and patients concerned are left in an uncertainly regarding the interpretation, diagnosis and prognosis of the discovered illness. PATIENT: The following case report focuses on this syndrome. CONCLUSION: The disease mainly affects young women and appears in the triple form of retinal arterial occlusion, hearing impairment and Encephalopathy.

Adult↗

PubMed1998

Comparison of buprenorphine and methadone in the treatment of opioid dependence. Swiss multicentre study.

A three-centre, randomised, double-blind study was designed to compare the efficacy and safety of buprenorphine and methadone. This was the first European study to compare these agents and was based on a previous trial performed in the US. Opioid-dependent subjects were randomised to receive either sublingual buprenorphine or oral methadone daily. Both objective and subjective measures of efficacy were monitored weekly, and safety parameters were regularly monitored over the entire six-week study. Urinalysis showed that the two treatments were similar with a slight increase in opioid-negative urines noted in both groups. The retention rate in the buprenorphine group was lower than in the methadone group, although it has been suggested that the buprenorphine dose may have been too low for some patients. None of the side effects noted were considered serious and all were attributable to chronic opioid dependence. Experience of two years substitution treatment in Fribourg suggests that initial induction onto buprenorphine allows for patients to be subgrouped before being given the most appropriate maintenance agent. Further investigation is required into the different dose-related effects of buprenorphine seen in particular subsets of addicts.

Adult↗

PubMed1993

Differences between long-stay and short-stay inpatients and estimation of length of stay. A prospective study.

To find possible differences between new long-stay inpatients and patients with shorter lengths of stay, a prospective study of 340 inpatients in the 4th week of hospitalization was carried out. The new long-stay patients differed from the others in diagnoses, symptoms, duration of prior hospitalizations, and socio-demographic data. On the basis of the data assessed in the 4th week of hospitalization, we tried not only to predict future new long-stay patients, but also to estimate the length of stay for all 340 patients. A time-function model was employed with length of stay as a continuous variable, and this resulted in correct allocation to the quartiles in 38-48% of the cases. Six variables proved to be important for estimating length of stay: emotional withdrawal, blunted affect, mannerisms, duration of previous hospitalizations, living conditions (prior to admission), and marital status.

Adult↗

PubMed1992

A study of suicide in schizophrenic in-patients.

A retrospective analysis of the clinical records of 53 schizophrenic in-patients who committed suicide, and the same number of matched control subjects, was carried out using a larger set of demographic, psychosocial and clinical variables. Univariate analysis of the data indicated an early disturbed psychosocial adjustment, more severe mental illness, unsatisfactory social situation, and more frequent suicidal behaviour in the suicide group. Suicide in schizophrenic in-patients thus appears to be closely connected with a particularly incapacitating form of the illness and its deleterious psychosocial consequences.

Adult↗