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Biomedical subjects

K Wessel

Publications and source records attributed to K Wessel.

At least 55 records · Page 3Linked to original sources
PubMed1997

Acute exacerbation of multiple sclerosis increases plasma levels of S-100 protein.

OBJECTIVES: To determine whether an increase in plasma concentration of S-100 protein can serve as a marker for acute exacerbation of multiple sclerosis. MATERIAL AND METHODS: The plasma level of S-100 protein was investigated in 28 patients suffering from multiple sclerosis. Of these, 17 patients were admitted for acute exacerbation and 11 patients had a stable disease with no clinical signs for acute exacerbation. S-100 protein concentrations in plasma were determined with an immunofluorometric sandwich assay. RESULTS: Plasma concentrations were significantly elevated in patients who were examined within 7 days after the onset of acute exacerbation (n = 6). S-100 levels of patients 8 to 28 days after the onset of acute exacerbation (n = 11) did not differ from healthy controls (n = 120). Eleven patients with multiple sclerosis without acute exacerbation had moderately elevated plasma levels. CONCLUSION: The plasma concentration of S-100 protein is a sensitive although unspecific indicator of neuronal damage and may be of use as a marker of disease activity in multiple sclerosis.

Acute Disease↗
PubMed1997

Basilar branch disease presenting with progressive pure motor stroke.

OBJECTIVES: Isolated infarcts of the pons cause well definable neurological syndromes with distinct pathomechanism, clinical course and prognosis. PATIENTS AND RESULTS: We report 8 cases suffering from a pure motor hemiparesis that was severely progressive within the 1st 3 days and unresponsive to aspirin. A relatively good recovery was observed in all patients, however, stroke recurrence occurred in 2 cases within 3 months and resulted in pseudobulbar paralysis and tetraparesis. MRI displayed unilateral (n=6) and bilateral (n=2) ventromedial pontine infarctions (VPI). Angiographic evaluation (n=4) or color Duplex examination (n=4) revealed atherosclerotic lesions but no basilar artery occlusion. CONCLUSION: Although VPI due to basilar branch disease may clinically mimic a classical lacunar syndrome, it is related to a particular pathogenetic mechanism different from microangiopathy or embolism. In contrast to the MRI feature of lacunes, VPI typically extend to the basal surface of the pons. The progressive pattern, ending up in a relative uniform clinical picture, is probably caused by propagating thrombosis.

Aged↗
PubMed1997

Self-paced versus metronome-paced finger movements. A positron emission tomography study.

To evaluate the hypothesis that self-paced movements are mediated primarily by the supplementary motor area, whereas externally triggered movements are mainly affected by the lateral premotor cortex, different movements in 6 healthy volunteers were studied while changes in regional cerebral blood flow (rCBF) were measured using positron emission tomography (PET) and 15O-labeled water. Subjects made a series of finger opposition movements initiated in a self-paced manner every 4 to 6 seconds, and separately, made continuous finger opposition movements at a frequency of 2 Hz paced by a metronome. The primary motor cortex, lateral area 6, cerebellum on both sides, and caudal cingulate motor area, and the putamen and thalamus on the contralateral side were more active during the metronome-paced movements. The increases in rCBF in these areas are likely the result of the larger number of movements per minute made with the externally triggered task. The anterior supplementary motor area and rostral cingulate motor area in the midline, prefrontal cortices bilaterally, and lobus parietalis inferior on the ipsilateral side were more active during the self-paced movements. Increases in rCBF in those areas, which include medial premotor structures, may be related to the increased time devoted to planning the movement in this condition.

Adult↗
PubMed1997

How to make an impression on members of Congress.

Individuals elect Members of Congress, and individuals can also affect what those elected officials do once in office. It is vitally important that agencies and individuals get involved in influencing what their representatives and senators do, as those congressional votes will have a direct impact on how the home care and home care aide industry does business.

Aged↗
PubMed1996

Enhancement of inhibitory mechanisms in the motor cortex of patients with cerebellar degeneration: a study with transcranial magnetic brain stimulation.

The excitatory state of the primary motor cortex can be studied by measuring either the postexcitatory inhibition after transcranial magnetic single stimulation (pI-S) or the refractory period with magnetic double stimulation (rP-D). The cerebellum may influence the excitability of the motor cortex by cerebellar inputs and outputs from side loops of transcortical projections. Therefore, we studied pI-S and rP-D in 24 patients with autosomal dominant cerebellar ataxia or idiopathic cerebellar ataxia, who were allocated to one group (Group A) with mild to moderate ataxia (n = 11) and to another group (Group B) with severe ataxia (n = 13). The results were compared with those obtained in 21 normal age-matched control subjects. The central motor conduction time (CMCT) was delayed in approximately half of the patients, demonstrating that the degenerative process, beyond the cerebellum, also affects the pyramidal tract. Mean CMCT was significantly delayed only in patients of Group B. pI-S was prolonged in 10 of our 24 patients; incidence of pathology in pI-S did not differ between the two patient groups. In 5 patients with normal CMCT, pathological pI-S results were found. Mean pI-S was prolonged in the whole patient group and in both subgroups as well. rP-D was prolonged in two patients of Group B only, but mean rP-D was significantly prolonged in the whole patient group. Prolonged postexcitatory inhibition and refractory period may be a consequence of a transient facilitation of cortical inhibitory interneurons, which results in a decreased excitability of primary motor cortex in patients with cerebellar degeneration.

Adult↗
PubMed1996

Somatotopic motor representation in the human anterior cerebellum. A high-resolution functional MRI study.

Though somatotopic encoding of function is a prominent feature in brain structures involved in sensori-motor processing, it has not been well established for the human cerebellum. We delineated the representation of hand, foot and tongue movements in the anterior cerebellar lobe of eight healthy subjects using dynamic high-resolution MRI sensitized to changes in cerebral blood oxygenation (CBO). Activation was determined by pixel-by-pixel correlation of signal intensity time courses with the performance protocol. All subjects showed task-related signal increases in an ipsilateral region during distal limb movements. For the hand task, the centre of activation was located in the intermediate hemispheric portion of Larsell lobules H IV-V. Foot movements activated areas within the central lobule, Larsell lobules II-III, medial and anterior to the corresponding hand areas in all subjects. Responses for tongue movements were less consistent across subjects but found in areas posterior to the respective individual hand representation.

Adult↗
PubMed1996

Online help: cancer patients participate in a computer-mediated support group.

This study investigated a computer mediated support group of six breast cancer patients. For a three-month period, patients used home computers to connect to a computer bulletin board on which they read messages from and posted messages to each other. The patients had no difficulty learning to use the computer and used it an average of one hour a week. The patients discussed their medical conditions, shared personal concerns, and offered support. This online approach provided many features of traditional face-to-face support groups.

Adult↗
PubMed1996

Speech timing in ataxic disorders: sentence production and rapid repetitive articulation.

We studied syllabic timing in patients with ataxia (10 with cerebellar atrophy, 6 with Friedreich's ataxia) under two conditions: in a "natural" sentence production context and in the context of a rapid syllable repetition task. The two tasks included comparable articulatory maneuvers. We measured syllable durations from the speech signal and analyzed variables describing average syllabic rate and within-trial variation of syllable durations. Among the observed measures, slowed syllable repetition was a particularly powerful predictor of the severity of dysarthric impairment. In sentence production, patients often performed at normal syllabic rates. Irregular pacing of syllable repetitions was frequent. Different patterns of between-articulator variation emerged in the two tasks. All patients except one were slower in rapid repetitive articulation than in sentence production. These data suggest that sentence production and rapid repetitive articulation are governed by basically different motor processes. The disproportionate slowing of ataxic patients in the repetitive task can be ascribed to adaptation to novel motor tasks being impaired in cerebellar disease.

Adolescent↗
PubMed1995

Double-blind crossover study with levorotatory form of hydroxytryptophan in patients with degenerative cerebellar diseases.

OBJECTIVE: To determine whether treatment with the levorotatory form of hydroxytryptophan (L-5-hydroxytryptophan), a controversial experimental drug, can improve the conditions of patients with ataxia. DESIGN: A double-blind crossover study with the levorotatory form of hydroxytryptophan was performed in 39 patients with degenerative cerebellar diseases. SETTING: Patients were selected from an ongoing prospective follow-up study at two university hospitals. PATIENTS: We studied 19 patients with Friedreich's ataxia, 13 with cerebellar atrophy, and seven with olivoponto-cerebellar atrophy. INTERVENTION: The levorotatory form of hydroxytryptophan was given orally in a dose of 1000 mg/d. Each treatment phase, with the levorotatory form of hydroxytryptophan or the placebo, lasted 10 months, after which the treatment of patients was crossed over to the other phase. MAIN OUTCOME MEASURES: Ataxia was documented and quantified by using a clinical score, posturography, and measurement of grip force and the rapid-syllable repetition rate. RESULT: The levorotatory form of hydroxytryptophan had no significant effect on cerebellar symptoms. CONCLUSION: Long-term treatment with a high dose of the levorotatory form of hydroxytryptophan does not improve the conditions of patients with ataxia.

5-Hydroxytryptophan↗
PubMed1995

Regional cerebral blood flow during a self-paced sequential finger opposition task in patients with cerebellar degeneration.

The brain regions controlling self-paced sequential finger movements in patients with cerebellar degeneration were studied by measuring changes in regional cerebral blood flow (rCBF) in eight patients using bolus injections of H2(15)O and PET. The results were compared with those obtained in eight normal age-matched control subjects. Patients and control subjects performed a self-paced sequential finger opposition task with the right hand, completing a sequence of movements every 4-6 s. Both groups had strong increases in the adjusted rCBF contralaterally in the primary motor cortex (M1) and ventral premotor area (PMv), in the caudal supplementary motor area (SMA) and cingulate motor area (CMA), and bilaterally in the prefrontal cortex (PFC), the lobus parietalis inferior (LPI), putamen and cerebellum. The cerebellum, PMv, rostral CMA, PFC and LPI were more active in the control subjects than in the patients, and the M1, SMA, caudal CMA and putamen were more active in the patients than in the control subjects. The reduced activity of the cerebellar neurons in the patients produced a complex pattern of rCBF increases and decreases in other brain regions. Our results suggest that for the preparation and execution of sequential finger movements, patients with cerebellar degeneration use a medial premotor system, including the SMA and caudal CMA, as well as the M1 and putamen, rather than the PMv, PFC, LPI and rostral CMA.

Adult↗
PubMed1995

[Coping pattern and adjustment in multiple sclerosis].

A questionnaire (FKV/LIS) was used to study the coping process in 210 patients with multiple sclerosis. By cluster analysis of five coping modes, patients could be divided into two groups of approximately the same size: cluster 1 presented with higher values for "active coping; self-affirmation; religiousness" and lower values for "depression" and "trivialization". In cluster 2, on the other hand, values were higher for "depression" and "trivialization" whereas values were lower for "active coping; self-affirmation; religiousness". Patients in cluster 1 were significantly more contented with life. Mean age and mean duration of illness were higher in cluster 1, suggesting a time-dependent change in the coping process with improvement in adaptation in the course of the disease. The extent of social support was higher in cluster 1. The consequences for psychological intervention are discussed.

Adaptation, Psychological↗
PubMed1995

Crossed R1 response of the blink reflex in peripheral facial palsy.

A patient with regenerated Bell's palsy showed a crossed R1 component of the blink reflex recorded from the healthy side while stimulating the affected side. Our observation supports the hypothesis that a short-circuit trigemino-facial pathway crossing the midline exists in normal subjects which is not activated under normal conditions, but may be engaged following peripheral facial nerve disease.

Adult↗
PubMed1994

Perturbation of precision grip in Friedreich's ataxia and late-onset cerebellar ataxia.

Perturbations of precision grip were tested in 7 patients with Friedreich's ataxia (FA) and 11 patients with late-onset cerebellar ataxia (CA). Subjects were instructed to hold a small compressible manipulandum between thumb and index finger and to resist any perturbation of maintained finger position. A sudden increase of load induced a displacement of fingers until this was stopped by subjects' active intervention. The amount of initial displacement emerged as a highly sensitive parameter to differentiate the clinical subgroups: Responses in FA patients were missing or massively delayed, whereas displacements in CA patients were normal or only moderately abnormal. This discrimination of impaired hand function in FA and CA patients has not been possible by using only tasks of isometric grip force control. We concluded that our task relies more on intact sensory afferents, which are known to be impaired in FA, than on cerebellar function. In a second task the stiffness of the maintained grip was determined. On the average, preresponse stiffness was lower in FA patients as compared with CA patients and normal controls. However, stiffness appeared to be an independent parameter that did not influence the amount of displacement in the perturbation task.

Adolescent↗
PubMed1994

Movement-related cortical potentials preceding sequential and goal-directed finger and arm movements in patients with cerebellar atrophy.

To determine the influence of cerebellar involvement on the preparatory state of the cerebral cortex for voluntary movements, we studied the movement-related cortical potentials (Bereitschaftspotential, BP) preceding sequential and goal-directed finger and arm movements in patients with cerebellar atrophy (CA). The first task (paradigm 1) consisted of a sequential finger movement at a self-paced rate of every 3 sec or longer, in which patients and control subjects pushed rapidly 7 keys on a keyboard in a sequence visually predetermined on a screen. The second task (paradigm 2) consisted of a goal-directed self-paced movement with visual feedback on a screen. In both paradigms, control subjects and patients had distinct movement-related cortical potentials, but peak amplitudes (close to movement onset) were reduced in the patient group (paradigm 2), whereas in the overall analysis the mean amplitude 600-800 msec before movement onset (NS1) was larger in the patient group (paradigms 1 and 2). Accordingly, the difference (NS2) between peak amplitude and NS1 was smaller in the patient group (paradigms 1 and 2). Whereas control subjects' peak amplitude (paradigm 2) and NS2 (paradigm 1) were focused at Cz, this topographical differentiation was abolished in the patient group. The onset of the BP was earlier in the patients than in the control subjects (paradigms 1 and 2). Our results suggest that pathways from the cerebellum to the cortex do play a role in generating movement-related cortical potentials. A strong input from the cerebellum seems to be crucial for the generation of a normal motor potential close to the movement onset, reflecting a specific deficit in patients with CA. Patients with CA may try to compensate for their motor deficits by a longer cortical activation preceding voluntary movements (earlier onset of the BP). The increased NS1 could be the result of larger effort, by which patients try to compensate for their motor deficits as well.

Adult↗
PubMed1994

Thalamic stroke: correlation of clinical symptoms, somatosensory evoked potentials, and CT findings.

We studied 18 patients with a single ischemic thalamic lesion, who had somatosensory disturbances and/or central pain in the opposite hemibody, by correlating their clinical symptoms, somatosensory evoked potentials (SEPs), and computed tomography (CT) findings. Patients were divided into three groups: (1) those with somatosensory deficits, central pain, and abnormal SEPs, which comprised two thirds of the patients (classic thalamic pain syndrome), (2) those with somatosensory deficits, no central pain, and abnormal SEPs (analgetic thalamic syndrome), and (3) those with almost normal sense perception, central pain, and normal SEPs (pure algetic thalamic syndrome). CT evidence of a paramedian or anterolateral thalamic lesion might be an indicator for the development of central pain, because these types of infarctions occurred only in patients with the classic thalamic syndrome or the pure algetic thalamic syndrome. The differentiation of the thalamic syndrome into three subtypes is of prognostic value, because patients with a loss of cortical SEPs and a posterolateral ischemic thalamic lesion on the CT scan probably will not exhibit central pain.

Aged↗
PubMed1993

Thrombosis of the right vein of Labbé: radiological and clinical findings.

A rare case of aseptic thrombosis of the right vein of Labbé in a young woman is reported. Cerebral venous thrombosis was suggested by computed tomography and confirmed by angiography. Mild left-sided neurological deficits resolved almost completely. The combination of a nonspecific clinical picture with an atypical lesion on CT may favour the diagnosis of cortical venous thrombosis.

Adult↗
PubMed1993

CT in autosomal dominant and idiopathic cerebellar ataxia.

Signs of atrophy on cranial CT were investigated in 35 patients diagnosed as suffering from autosomal dominant (n = 21) or idiopathic (n = 14) cerebellar ataxia. Thirteen patients with a pure cerebellar syndrome were examined after at least 4 years of disease (mean duration 10.5 years) and were classified as cerebellar atrophy (CA). Twenty-two patients with additional non-cerebellar signs were classified as olivo-ponto-cerebellar atrophy (OPCA). Four (30%) of the patients with CA had atrophy of the brain stem in addition. Of the 22 patients with OPCA, 9 (40%) had atrophy of the cerebellum only. In patients with CA or OPCA correlation of clinical signs with severity of atrophy on CT was poor. Atrophy on CT often fails to differentiate autosomal dominant or idiopathic cerebellar ataxias in CA or OPCA: patients with CA can also have atrophy of the brain stem and patients with OPCA do not necessarily show brain stem atrophy.

Adult↗