Biomedical subjects

A Hähnel

Publications and source records attributed to A Hähnel.

6 recordsLinked to original sources

PubMed2003

[Referral by a general practitioner versus self-referral to a specialist practice. A comparison using chronic venous insufficiency as an example].

BACKGROUND AND OBJECTIVE: The gate-keeping role of general practitioners (GPs) is currently the topic of much debate in Germany. Currently it is possible for patients in Germany to see a specialist either through referral by their GP or directly through self-referral. To determine whether the gate-keeping role of GPs has a filtering effect, we compared patients referred by their GPs with self-referred patients presenting with suspected chronic venous insufficiency (CVI) to a specialist practice. PATIENTS AND METHODS: From September to December 2001, we prospectively recruited 316 patients seen for suspected CVI in a specialist practice for vascular surgery and phlebology. Symptoms and clinical findings were recorded using a standardized form. RESULTS: 58.2 % of patients were referred by their GPs. These patients were on average 6 years older and presented at a more advanced stage of disease than self-referred patients. No difference was found between patients with and without referral with respect to the symptoms reported or the therapy recommended by the specialist. CVI was excluded in 7.1 % of patients with a referral and in 6.8 % of those without a referral. CONCLUSIONS: The majority of patients consulting a specialist were referred by their GP. The more advanced disease stage of these patients indicates that a filtering process occurs in referral by GPs. However, the share of patients without referrals in whom CVI could be excluded was low and not significantly different from that of patients with referrals. This indicates that misdiagnosis due to self-referral is relatively modest. A cost reduction effect in a gate-keeper system could therefore only be small.

Adult↗

PubMed2001

Using temporal information to construct, update, and retrieve situation models of narratives.

Four experiments explored how readers use temporal information to construct and update situation models and retrieve them from memory. In Experiment 1, readers spontaneously constructed temporal and spatial situation models of single sentences. In Experiment 2, temporal inconsistencies caused problems in updating situation models similar to those observed previously for other dimensions of situation models. In Experiment 3, merely implied temporal order information was inferred from narratives, affecting comprehension of later sentences like explicitly stated order information. Moreover, inconsistent temporal order information prevented the creation and storage in memory of an integrated situation model. In Experiment 4, a temporal inconsistency increased processing time even if readers were unable to report the inconsistency. These results confirm the significance of the temporal dimension of situation models.

Adult↗

PubMed1999

[Strategic focusing of attention during narrative reading].

In 2 experiments based on the constructionist view of text comprehension, we investigated whether readers are able to strategically use, in a problem solving matter, spatial and temporal information that varies in its relevance to the goals of the protagonists. In order to accomplish this, we varied the specificity of the protagonists' goal descriptions. Both experiments consisted of a reading section, a test, and a questionnaire, and differed only in respect to when the questionnaire was administered. The results of both experiments showed that readers were able to use spatial and temporal information of narrative texts in a strategic matter, and they even did so without explicit instruction. This focus of attention, however, was not uniformly reflected in the reading times. Memory data showed a clear disadvantage for temporal information as compared to spatial information. This was the case even though both types of information had been equally well identified in the questionnaire as crucial to the problem solving process of the protagonist.

Attention↗

PubMed1997

The metrics of spatial situation models.

The authors investigated the metrics of spatial distance represented in situation models of narratives. In 3 experiments, a spatial gradient of accessibility in situation models was observed: The accessibility of objects contained in the situation model decreased with increasing spatial distance between the object and the reader's focus of attention. The first 2 experiments demonstrated that this effect of spatial distance was purely categorical rather than Euclidean: Accessibility depended on the number of rooms located between the object and the focus of attention, not on the size of the rooms. Experiment 3 revealed, however, that participants were able to use information about Euclidean distance in a secondary task when necessary. The implications of these results for theories of narrative comprehension and hierarchical versus nonhierarchical theories of spatial memory are discussed.

Adult↗

PubMed1990

[Clinical value of antibody titers to Borrelia burgdorferi and titer course in neurologic disease pictures].

Over a period of 3 years, antibody titres against Borrelia burgdorferi in serum were determined for 492 patients with a wide spectrum of neurological diseases. Using the ELISA technique, we found elevated titres against Borrelia burgdorferi in about 20% of these patients. Cranial nerve paresis was often the leading symptom of an acute Neuroborreliosis. In a number of cases the diagnosis was indicated only by an elevated IgG titre in the patient's serum, or a decrease in the titre level following antibiotic treatment. The IgG titres are, however, unsuitable for control of therapy. Non-specific parameters of inflammation such as blood sedimentation rate (BSC), C-reactive protein (CRP), serum-electrophoresis or leucocyte count are also unsuitable in evaluating the therapeutic effect or for confirming the diagnosis. The most important diagnostic criterion is the demonstration of Borrelian antibodies, synthesised locally in cerebrospinal fluid (CSF). A spirochaete index above 2 suggests autochthonous intrathecal antibody production. This procedure corresponds to the determination of intrathecally produced Treponema pallidum antibodies in neurolues from quantitative TPHA values and total IgG in serum and CSF (ITpA Index according to Prange).

Adolescent↗

PubMed1989

Effective treatment of chronically progressive multiple sclerosis with low-dose cyclophosphamide with minor side-effects.

Twenty-one multiple sclerosis (MS) patients with a chronically progressive course were treated with a low dose of cyclophosphamide (CY). The control group consisted of 21 MS patients with a chronically progressive course who received the standard treatment (ACTH or cortisone). The control group consisted of patients who preferred the standard therapy because of its beneficial effects. In contrast, the patients of the CY group wanted to try a new therapy because the standard therapy was not effective. Thus before starting the study the progression of the disease was faster in the CY group than in the standard therapy group. As regards age, sex and degree of disability, the two groups were comparable. For 20 of the 21 patients in the CY group the degree of disability (Kurtzke scale) remained stable over 1 year; for 2 of the 20 stable patients there was even an improvement. In the standard therapy group, 7 out of 21 patients were stable over 1 year, while 14 showed progressive disability. A quantitative neurological score at the beginning and 1 year after the therapy showed a nearly identical difference between the CY group and the control group. The changes of the patients' abilities in daily-life activities (which were observed and recorded by the nurses) were similar to the Kurtzke scale data obtained by the physicians. The beneficial effect of CY in chronically progressive MS was thus highly significant (P less than 0.001). The side-effects of low-dose CY were fewer than those of ACTH.

Adult↗