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Biomedical subjects

F Staub

Publications and source records attributed to F Staub.

At least 19 recordsLinked to original sources
PubMed2006

Intentional motor phantom limb syndrome.

OBJECTIVE: To investigate the clinical and anatomic correlates of a previously unreported form of chronic supernumerary phantom limb, which developed only in association with motor intent directed at a hemiplegic-anesthetic upper limb. METHODS: We explored the phenomenology of the phantom illusion in the light of motor control models. Hemodynamic correlates of supernumerary phantom limb were studied with an fMRI sensorimotor paradigm consisting of finger-thumb opposition movements. RESULTS: The kinesthetic-proprioceptive illusion of a third arm was triggered by any attempt to move the paretic limb, by bimanual actions, and by motor imagery involving the nonfunctional limb. The responsible lesion destroyed the posterior part of the posterior limb of the internal capsule on the opposite side, damaging corticospinal and thalamocortical tracts. Comparison between fMRI signals performed during virtual movement of the phantom hand vs imaginary movement of the paretic hand showed increased activation in thalamus and caudate nucleus in the first condition. CONCLUSIONS: A preserved sense of agency provided by intact premotor processes translating intention into action may lead to the vivid feeling of movement in a paralyzed limb, similar to kinesthetic illusions in amputees. The interruption of thalamic afferences may explain the persistence and stability of the phantom by preventing any correction of the mismatch between expected and effective movement. The increased blood oxygen level-dependent (BOLD) signal in the basal ganglia-thalamus-cortex pathway during movement of the supernumerary hand may reflect an abnormal closed-loop functioning of the thalamocortical system underlying the phantom phenomenon.

Aged↗
PubMed2006

Chronic posttraumatic stress symptoms after nonsevere stroke.

OBJECTIVE: To determine whether posttraumatic stress disorder (PTSD)-related symptoms were present 1 year after a nonsevere stroke and, if so, to examine the relationship between PSTD, coexisting cognitive variables, and infarct localization METHODS: The authors assessed 49 patients using standard measures of memory, trauma experience, neurologic deficit, depression, anxiety, and PTSD. RESULTS: Fifteen (31%) patients had significant PTSD symptoms on the Impact of Event Scale (IES > 30). PTSD-like syndrome was independent of neurologic impairment, peristroke amnesia, long-term memory impairment, nosognosia, hypochondriac preoccupations, and physical pain during hospitalization, but was more frequent in women, less educated patients, and patients with more negative appraisals of the stroke experience. Intrusions were increased after basal ganglia strokes, suggesting that the re-experiencing phenomena may be modulated by frontosubcortical pathways. CONCLUSIONS: Posttraumatic stress disorder symptoms seem frequent in patients with nonsevere stroke and were associated with the subjective intensity of the stroke experience and accompanied by a depressive and anxious state.

Adult↗
PubMed2006

[The iatrogenic carpal tunnel syndrome--case report].

An inadequate indication for a carpal tunnel revision procedure may be followed by disastrous sequelae for the patient. So it may be justified to talk of iatrogenic CTS. A patient suffering from bilateral CTS is presented who had been operated on six times in all. The following techniques had been used by an orthopedic surgeon, a neurologist, a neurosurgeon and a hand surgeon: microsurgical neurolysis, epineurectomy, neuroma resection, tenosynovectomy and finally a hypothenar fat flap. Initial cause for this fatal series was scar tenderness following lesion of the muscular and palmar branches of the median nerve in the first or second operation. Since sensory nerve conduction was normal after decompression had been performed, there would have been no indication for further surgery of the median nerve. Resection of the neuromas of the two injured branches was not followed by any relief for the patient nor did wrapping the nerve in a fat flap help. Such courses may lead to high costs in health care and occupational disability. They can be avoided by competent neurological and electrophysiological examination, correct interpretation of findings as well as critical consideration of the indication for revision procedures.

Carpal Tunnel Syndrome↗
PubMed2006

[Reoperations for CTS because of recurrence or for correction].

BACKGROUND: With an increasing number of operative procedures for CTS, the number of reoperations is increasing too. These procedures are not in general performed because of recurrence, other reasons may play a role for the failure of the initial operation or recurrent symptoms. METHODS AND CLINICAL MATERIAL: Revision procedures performed in 57 patients in the practice for peripheral neurosurgery from January to September 2004 were analyzed for incision, intraoperative findings, method of operation, electrophysiological findings, and revised diagnosis. Moreover, the data were compared with 185 revision procedures performed in the years from 1986 up to 1994. RESULTS: 2.4 % of all CTS operations were revision procedures (in the former time period 1.5 %). In 59 % of revision operations (former 50 %) an incomplete release of the transverse ligament was found, in 27 % (former 31 %) typical recurrence, in 5 % (former 6 %) nerve lesions, and in 9 % (former 13 %) no abnormalities so that other reasons for complaints of mainly radicular lesions must be assumed. In cases of incomplete release of the transverse ligament, only in 16 % of the patients were normal skin incisions seen, but in 56.3 % there were small incisions (i.e., short or mini-incisions). Typical CTS recurrence occurred mainly in hemodialysis patients, nerve lesions were seen mainly when endoscopic procedures were performed. CONCLUSION: Diagnostic problems because of incomplete or misinterpreted ENG findings may lead to delayed or useless primary as well as revision operations. Too small incisions but also endoscopic procedures used by less experienced surgeons are accompanied with an increased risk for avoidable revisions and nerve lesions. Not only for forensic reasons but also in view of quality management, procedures for correction (of operative failure) should be distinguished from those for recurrence.

Ambulatory Surgical Procedures↗
PubMed2005

A prospective study of predictors of poststroke depression.

OBJECTIVE: To investigate the association between early depressive behavior after stroke onset and occurrence of poststroke depression (PSD) at 3- and 12-month follow-up evaluations. METHODS: The study prospectively included 273 patients with first-ever single uncomplicated ischemic stroke. In the stroke unit, nurses scored crying, overt sadness, and apathy daily using an observational method to include patients with comprehension deficits. The Barthel Index was used to assess disability. Follow-up evaluation at months 3 and 12 included psychiatric assessment based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition. RESULTS: Crying (19.8%), overt sadness (50.5%), and apathy (47.6%) were observed. Of the patients observed crying, 4 showed pathologic crying, 19 emotionalism, and 12 catastrophic reactions. Crying and overt sadness, but not apathy, were associated with a subjective experience of depression (p < 0.05). Thirty of 52 (58%) patients observed crying, 12 of 19 (63%) patients with emotionalism, and 5 of 12 (41%) patients with catastrophic reactions developed PSD within the first year. Multiple logistic regression analysis showed that only severe functional disability (odds ratio [OR], 4.31; 95% CI, 2.41 to 7.69), crying behaviors (OR, 2.66; 95% CI, 1.35 to 5.27), and an age <68 years (OR, 2.32; 95% CI, 1.30 to 4.13) were (p < 0.05) predictors of late PSD development (13% of the variance). CONCLUSIONS: In the stroke unit, crying and overt sadness are more reliable indicators of depressed mood than apathy. In patients with first-ever stroke, crying behaviors soon after stroke, a younger age, and severe disability are predictors of poststroke depression occurrence within the first year after stroke onset.

Aged↗
PubMed2005

[Recurrences of carpal tunnel syndrome in long-term haemodialysis patients].

BACKGROUND: Multiple recurrences of carpal tunnel syndrome and increased malfunction of the hand caused by tendopathies and arthropathies occur in long-term (20 - 30 years) haemodialysis and are mainly influenced by beta2-microglobulin amyloidosis. METHOD AND CLINICAL MATERIAL: 18 patients undergoing haemodialysis for an average of 29 years had been operated on 96 times for bilateral CTS and recurrent CTS during a mean observation period of 12.6 years. In nine patients (12 hands), removal of the thickened flexor digitorum superficialis tendons III and IV had been performed. All but two patients suffered from amyloidosis, 17 of them suffered from additional tendo- and 13 from additional arthropathies. All procedures were performed under local anaesthesia, and in half of them a tourniquet was used. The outcome was evaluated both clinically and with nerve conduction studies. RESULTS: 77 procedures for CTS-recurrences were performed. The first recurrence was observed after an average of 6.1 years (SD 2.8), the second after 4.6 (SD 3.1) and the third after 3.8 (SD 1.9) years. Whereas in case of a first (occasionally second or extremely seldom in a third) recurrence, another re-opening of the carpal tunnel with or without synovectomy, was sufficient to improve symptoms in the majority of patients, this was occasionally the case with a second but rarely with the third recurrence. In these latter patients, only resection of thickened superficial flexor tendon bundles, showing marked amyloid-deposits histologically, resulted in improvement of pain, as well as finger mobility in one third of the patients. The distal motor latency of the median nerve recovered after the primary operation in 86 %, and after the second (first recurrence) only in 53 %. After the third operation (second recurrence), the results after tendon removal were better than in cases after synovectomy alone. CONCLUSION: In long-term (more than 20 - 30 years) haemodialysis patients suffering from arthropathies, tendopathies and recurrent carpal tunnel syndrome, removal of the flexor digitorum superficial tendons should be considered for the second recurrence to improve pain and finger mobility.

Aged↗
PubMed2005

[Carpal tunnel syndrome in haemodialysis patients: analysis of clinical and electrophysiological findings in 268 patients (395 hands)].

PURPOSE/BACKGROUND: Along with arthropathies, carpal tunnel syndrome (CTS) may occur in patients on chronic haemodialysis, its incidence is correlating with the duration of the haemodialysis treatment. To evaluate clinical and electrophysiological findings, relation of the disease to the side of the arteriovenous shunt, gender ratio, and a concurrent tendovaginosis stenosans (TVS), 268 haemodialysis-patients with CTS or recurrent CTS were retrospectively analyzed. METHODS AND (CLINICAL) MATERIAL: Over a period of ten years (1994 - 2003), 268 haemodialysis patients presented to our peripheral neurosurgery practice with CTS or recurrent CTS. Diagnosis was confirmed with clinical and electrophysiological findings. The patients were divided into three groups based on their severity of disease as follows: Patients with only intermittent paraesthesias (CTS I degrees ), with persistent numbness in the area supplied by the median nerve (CTS II degrees ), and with paresis of the thenar muscles (CTS III degrees ). The average distal motor latency (DML), loss of sensory nerve action potentials (SNAP), and/or motor action potentials (MAP) were used as electrophysiological parameters. RESULTS: During the above mentioned period, 395 primary CTS-operations were performed in 268 patients, and 83 operations of recurrent CTS in 53 patients, i.e. approximately 50 % of the patients had bilateral operations. A second recurrency of CTS was treated in 29 hands of 20 patients and a third recurrency in six hands of five patients. The ratio of women to men suffering from CTS was approximately 1 : 1. TVS occurred concurrent in 22 % of the patients in one hand and in 11.6 % in both hands. Decompression of the median nerve was performed more frequently on the shunt-side, or primarily on the shunt-side, if both hands were affected, as compared to the contralateral side. Recurrency of CTS, possibly a second or third recurrency, was found with increasing time of dialysis. The temporal interval from one operation to the other had a declining tendency. Whereas at the time of the primary operation in 27.4 % of the patients a CTS I degrees was found, patients suffered from CTS II degrees or III degrees in case of a second or third recurrency. Deterioration of clinical signs in CTS recurrency was reflected by the electrophysiological findings with an increasing loss of SNAP and MAP. CONCLUSION: CTS is a typical complication of chronic haemodialysis, and differs from idiopathic CTS by a gender ratio of 1 : 1, a high frequency of concurrent TVS, as well as a tendency to recur. Since compression of the median nerve was found preferentially on the shunt-side, haemodynamic factors may play a role in the pathogenesis of the disease in addition to amyloidosis. Haemodialysis patients complaining of paraesthesia in their hands should undergo electrophysiological examination, even if a successful CTS-operation was performed in the past.

Aged↗
PubMed2005

Diseases of the nervous system: patients' aetiological beliefs.

BACKGROUND: Patients' opinions about the aetiology of their disease and the implications for compliance have not been well documented at this time. OBJECTIVE: To investigate prospectively aetiological beliefs of a cohort of neurological inpatients. METHODS: Within two days of admission, patients orally answered a short questionnaire regarding their beliefs about the aetiology of their disease and the possible influence of psychological factors, stress, fatigue, excessive work or other activities, poor lifestyle, conflict with another person, a tragic event, chance, and destiny. RESULTS: Of the 342 patients who participated in the study, 49% spontaneously said that they had no idea of what could have caused their disease, 15% gave a congruent medical explanation, 11% mentioned stress and fatigue as a precipitating factor, and 6% evoked a non-congruent medical explanation. Thirty six per cent thought that psychological factors had triggered their disease; such factors being blamed by a higher proportion of young patients and patients with chronic central nervous system diseases. The triggering factors most often blamed were stress (48%, especially by patients with headache), fatigue (51%), chance (54%), and destiny (43%). CONCLUSIONS: Patients' aetiological beliefs only partially concur with medical opinion and this may influence compliance with treatment. This statement should be explored and confirmed by further studies-for example, in cerebrovascular risk factor follow up.

Aged↗
PubMed2004

[Postmastectomy lymphedema and carpal tunnel syndrome. Surgical considerations and advice for patients].

PURPOSE: Following surgery for breast cancer, an increased risk is assumed for development or worsening of lymphedema following hand surgery procedures. The aim of this study was to find out whether surgery performed with exsanguination using a pneumatic tourniquet has any disadvantages under these circumstances. There might result consequences for patients' information of possible risks as well as for performance of hand surgical procedures. METHOD: 52 patients who had undergone mastectomy were included in the study. In 47 of these, axillar lymph node biopsy or dissection had been performed. 41 patients had been advised not to allow measurement of blood pressure, drawing of blood or surgery to that arm. Surgical release of the retinaculum flexorum by using local anesthesia and exsanguination for a maximum of ten minutes was performed at an average of 7.5 (range from 1 - 26) years after the breast operation. RESULTS: Following release of the carpal ligament a temporary swelling of the arm or hand was found in four patients, which persisted for 2 - 3 months in one patient and disappeared within one week in the others. Three patients suffered from moderate lymphedema before surgery. It was unaffected by hand surgery in two patients and only temporarily worsened for several days in another patient. In all patients, neurological symptoms (paresthesia, numbness and pain) improved completely. Other complications, particularly infections, were not observed. CONCLUSIONS: 1. Exaggerated information of patients with breast surgery in their history does not seem to be indicated in minor hand surgical procedures. 2. The hand surgeon should inform the patients preoperatively that there may occur a transient swelling which can be avoided by loose dressings and early functional training. Using a pneumatic tourniquet has no adverse effect on existing lymphedema in short lasting procedures. 3. Since patients after mastectomy and/or axillary dissection often complain about arm pain and paraesthesia, not only brachial plexus pathology but also a carpal tunnel syndrome must be considered.

Adult↗
PubMed2003

Identification of malignant brain edema after hemispheric stroke by PET-imaging and microdialysis.

Cerebral blood flow (CBF) and extent of irreversible tissue damage as well as the time course of extracellular concentration of amino acids, substrates of energy metabolism, and purine metabolites, intracranial pressure and tissue oxygen tension were assessed in 34 patients with large strokes covering more than 50% of the MCA territory. The results were compared to findings in the experimental model of transient (for 3 hours) MCA occlusion in cats. In the experimental model as well as in the clinical setting development of malignant brain infarcts (due to formation of space occupying brain edema) was predicted by the size of critically hypoperfused tissue and the volume of irreversibly damaged tissue. The course of malignant infarcts was characterized by progressive increase in concentrations of excitatory amino acids, lactate, pyruvate, glycerol, hypoxanthine and in intracranial pressure, while cerebral perfusion pressure and tissue oxygen tension decreased. These results clearly differentiate a malignant from a benign course of large hemispheric infarction. The methods can be used to identify patients at risk for formation of space occupying edema and to select patients who could benefit from invasive therapeutic strategies.

Amino Acids↗
PubMed2001

Fatigue after stroke: a major but neglected issue.

Subjective fatigue, defined as a feeling of early exhaustion developing during mental activity, with weariness, lack of energy and aversion to effort, remains virtually unstudied in patients with stroke, bur recent surveys suggest that it is a major, commonly overlooked, stroke sequela. While the few existing series did not show significant correlations between fatigue and stroke severity, lesion location, cognitive and neurological impairment and depression, recent neurobehavioral studies have highlighted an association between fatigue and brainstem and thalamic lesions. This suggests that fatigue may be linked to the interruption of neural networks involved in tonic attention, such as the reticular activating system. In fact, several subtypes of fatigue may develop after stroke, in connection with cognitive sequelae, neurological impairment, psychological factors and sleep disorders. A challenge is to identify and delineate these different subtypes and to distinguish them from mood disorders, which frequently coexist. We emphasize the concept of 'primary' poststroke fatigue, which may develop in the absence of depression or a significant cognitive sequela, and which may be linked to attentional deficits resulting from specific damage to the reticular formation and related structures involved in the subcortical attentional network. In the patients with excellent neurological and neuropsychological recovery, poststroke fatigue may be the only persisting sequela, which may severely limit their return to previous activities. The recognition of poststroke fatigue may be critical during recovery and rehabilitation after stroke.

Fatigue↗
PubMed2001

Predictive value of neurochemical monitoring in large middle cerebral artery infarction.

BACKGROUND AND PURPOSE: Space-occupying brain edema is a life-threatening complication in patients with large hemispheric stroke. Early identification of patients at risk is necessary to decide on invasive therapies such as decompressive hemicraniectomy or hypothermia. To assess potential predictors of malignant brain edema by measurement of intracranial pressure (ICP) and microdialysis in patients with large hemispheric stroke and different clinical course. METHODS: In an ongoing prospective clinical study, an ICP and microdialysis probe were placed into the parenchyma of the ipsilateral frontal lobe of 10 patients. Extracellular concentrations of glutamate, lactate, pyruvate, and glycerol were measured continuously. Repeated cranial CT scans were scrutinized for size of infarction and presence of mass effect. RESULTS: The dynamics of the different substances varied in accordance with the clinical course, size of infarction, and local brain edema: Increase in ICP and in glutamate concentration and lactate-pyruvate ratio was followed by massive edema and large infarcts; generally low and stable ICP and substrate concentrations were found in patients without progressive space-occupying infarcts. CONCLUSIONS: In patients with large hemispheric infarction, bedside monitoring with microdialysis is feasible and might be helpful together with ICP recording to follow the development of malignant brain edema.

Adult↗
PubMed2000

Mechanisms of arachidonic acid induced glial swelling.

Accumulation of arachidonic acid (AA) in the brain during ischaemia may contribute to development of brain oedema. In this study we investigated the effect of selected drugs on AA-induced cytotoxic brain oedema in C6 glioma cells. Suspended C6 glioma cells were preincubated with drugs and AA (0.1 mM) was added. When no drug was administered cell volume increased immediately after the addition of AA with a maximum cell swelling of 13.1+/-1.9% at 15 min (mean +/- S.E. M.). Preincubation of cells with BW 755C, a dual inhibitor of cyclo- and lipoxygenases, showed no reduction in cell swelling from AA, whereas superoxide dismutase, amiloride and the protein kinase inhibitor H-9370 led to a significant attenuation of volume increase (p<0.05). The role of Na(+) ions during cell swelling from AA was evaluated after pretreatment of C6 glioma cells with ouabain. This resulted in a reversal of cell swelling (p<0.01). We conclude that there is potential involvement of free radicals, signal transduction systems and intracellular accumulation of Na(+) ions in glial cell swelling from AA.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed2000

Effect of hypothermia on the volume of rat glial cells.

1. The cell volume of suspended C6 glioma cells and primary cultured rat astrocytes was measured at normothermia (37 degrees C), and at mild (32 degrees C) and moderate (27 degrees C) hypothermia by flow cytometry with electrical cell sizing. 2. Under control conditions (37 degrees C), C6 glioma cells had a volume of 809 +/- 29 microm3. Moderate hypothermia (27 degrees C) led to rapid cell swelling, with a maximum volume of 113.1 +/- 1.3 % of control being achieved after 50 min. After rewarming to 37 degrees C, cell volume recovered very slowly and incompletely (to 107.2 +/- 0.4 % of control). Less severe hypothermia (32 degrees C) led to a smaller increase in cell volume (108.7 +/- 0.5 % of control). 3. The maximal cell swelling response and the kinetics of swelling were similar in C6 glioma cells and primary cultured astrocytes. 4. Hypothermia-induced cell swelling was dependent on the presence of extracellular Na+ and was reduced by the Na+-H+ antiporter inhibitor EIPA. 5. The underlying mechanisms of hypothermia-induced cell swelling are an intracellular accumulation of Na+ by (1) differential effects of hypothermia on the membrane permeabilities of Na+ and K+ and (2) activation of the Na+-H+ antiporter by a shift of its activation curve to a more alkaline value.

Animals↗
PubMed2000

Interhemispheric transfer of visual motion information after a posterior callosal lesion: a neuropsychological and fMRI study.

Interhemispheric transfer of visual information was investigated behaviourally and with functional magnetic resonance imaging (fMRI) 6 months after a lesion of the posterior two-thirds of the corpus callosum. On tachistoscopical left hemifield presentation, the patient was severely impaired in reading letters, words and geographical names and moderately impaired in naming pictures and colours. In contrast, interhemispheric transfer of visual motion information, tested by verbal report of the direction of short sequences of coherent dot motion presented within the left hemifield, was preserved. The pattern of cerebral activation elicited by apparent motion stimuli was studied with fMRI and compared to that of normal subjects. In normal subjects, apparent motion stimuli, as compared to darkness, activated strongly striate and extrastriate cortex. When presented to one hemifield only, the contralateral calcarine region was activated while regions on the occipital convexity, including putative area V5, were activated bilaterally. A similar activation pattern was found in the patient with a posterior callosal lesion; unilateral left or right hemifield stimulation was accompanied by activation in the contralateral and ipsilateral occipital convexity. Ipsilateral hemifield representation in the extrastriate visual cortex is believed to depend on callosal input. Our observation suggests that this is not the case for visual motion representation and that other, probably parallel, pathways may mediate visual motion transfer after posterior callosotomy.

Adult↗
PubMed2000

Contribution of anion transporters to the acidosis-induced swelling and intracellular acidification of glial cells.

This study examines the contribution of anion transporters to the swelling and intracellular acidification of glial cells from an extracellular lactacidosis, a condition well-known to accompany cerebral ischemia and traumatic brain injury. Suspended C6 glioma cells were exposed to lactacidosis in physiological or anion-depleted media, and different anion transport inhibitors were applied. Changes in cell volume and intracellular pH (pH(i)) were simultaneously quantified by flow cytometry. Extracellular lactacidosis (pH 6.2) led to an increase in cell volume to 125.1 +/- 2.5% of baseline within 60 min, whereas the pH(i) dropped from the physiological value of 7.13 +/- 0.05 to 6.32 +/- 0.03. Suspension in Cl(-)-free or HCO(3)(-)/CO(2)-free media or application of anion transport inhibitors [0.1 mM bumetanide or 0.5 mM 4, 4'-diisothio-cyanatostilbene-2,2'-disulfonic acid (DIDS)] did not affect cell volume during baseline conditions but significantly reduced cell swelling from lactacidosis. In addition, the Cl(-)-free or HCO(3)(-)/CO(2)-free media and DIDS attenuated intracellular acidosis on extracellular acidification. From these findings it is concluded that besides the known activation of the Na(+)/H(+) exchanger, activation of the Na(+)-independent Cl(-)/HCO(3)(-) exchanger and the Na(+)-K(+)-Cl(-) cotransporter contributes to acidosis-induced glial swelling and the intracellular acidification. Inhibition of these processes may be of interest for future strategies in the treatment of cytotoxic brain edema from cerebral ischemia or traumatic brain injury.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗