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Biomedical subjects

A Zieger

Publications and source records attributed to A Zieger.

13 recordsLinked to original sources
PubMed1998

Differentiation of autonomic nervous activity in different stages of coma displayed by power spectrum analysis of heart rate variability.

The analysis of heart rate (HR) variability offers a noninvasive method to investigate autonomic nervous system activity in comatose patients. We analyzed three components of the HR variability in a group of comatose patients: the low-frequency band (LF), representing mainly sympathetic influence, the mid-frequency band (MF), representing sympathetic and parasympathetic influence, and the high-frequency band (HF), representing the parasympathetic influence. A value for sympathovagal balance was defined as LF/HF and MF/HF ratio. Moreover, the skin conductance level (SCL) and the skin conductance resistance (SCR) variability were recorded. The patient group consisted of 22 patients with traumatic brain injuries. Coma depth was assessed by the Glacow Coma Scale and artifact-free HR, SCL, and SCR were measured 75 times in the patient group. The results documented a significant gain in sympathetic nervous system activity corresponding with the state of emerging from coma. This gain was most pronounced in the HF component of the HR and in the sympathovagal balance between LF/HF. The findings in SCL and SCR variability endorsed this result. It is concluded that emerging from coma is accompanied by an increasing influence of the sympathetic nervous system on HR control. This leads to a change in the sympathovagal balance, i.e., a reintegration of parasympathetic and sympathetic activity.

Adolescent↗
PubMed1998

[New research and considerations in managing minimally conscious coma patients].

The "Wachkoma", minimally conscious state (synonyms in use: "apallic syndrome", "vegetative state"), is a severe, complex condition arising from brain damage of diverse etiologies, for which definitional consensus does not exist internationally; it gives rise to frequent misdiagnosis and carries substantial insecurities concerning treatment outcomes. In the framework of expanding early rehabilitation, however, recent years have seen a distinct shift away from a defect-oriented, reductionist view towards a relational-medicine based understanding of patients with severe brain damage, seeking to gain a comprehensive perception of the patient's altered physical existence and taking a multidisciplinary--nursing, medical, therapeutic and neuropsychological--perspective which includes the patient's relatives and family. Historically, a transition is under way away from the classical brain-pathology focus toward a neuropsychologically grounded, differentiated perspective. Along with in-depth differential diagnostics and assessment of rehab potentials (early intervention diagnostics), comprehensive intervention measures are initiated as early as possible by an interdisciplinary team. These include "coma stimulation" measures, body language forms of interaction ("dialogue management"), and technical communication devices. By building long-term care assistance in ambulatory and residential service delivery systems ("small social network"), social reintegration of these very severely affected patients is attempted, involving the familial and social resources available. Recurrently raised within the bioethical discourse, demands to consider doctor-assisted dying or food withdrawal are to be rejected from a clinical, medical and social-ethical perspective.

Brain Damage, Chronic↗
PubMed1995

Unconscious activation of motor responses in a hemiplegic patient with anosognosia and neglect.

Unconscious processing of environmental stimuli has been convincingly demonstrated for a large number of neuropsychological syndromes. However, only few studies have successfully recorded on-line the activation of the autonomous or the motoric nervous systems. The activation of the motor system by unconscious stimuli would be a strong argument that information processing in the brain is not organized into two serial steps (stimulus identification first, response selection second). This would argue for parallel processes of stimuli identification routines and response selection mechanisms on the basis of only provisionally worked out stimulus features. Investigating an anosognostic patient we found electrodermal activity (EDA) and electromyographic responses (EMG) to bimanual tasks, mental imagery, and to the request to execute specific actions. But overt behavior remained hemiplegic and the patient was unable to feel any kind of control of her paralyzed left arm and hand. Generally, the data can be interpreted along the lines of a theory of two different routes to action, leaving the unconscious selection of action patterns intact, whereas the intentional triggering of overt behavior with the left hand and arm was impossible for the patient.

Brain↗
PubMed1994

Usefulness of bioelectric impedance and skinfold measurements in predicting fat-free mass derived from total body potassium in children.

Despite the increasing use of tetrapolar whole-body bioelectric impedance (BI) analysis in the assessment of body composition, its usefulness in estimating fat-free mass (FFM) has not been evaluated in comparison with conventional skinfold anthropometry in children. We therefore compared 1) the intraobserver and interobserver reproducibility of BI and skinfold measurements and the derived FFM estimates, and 2) the predictability of FFM as calculated from measurements of total body potassium (TBK) using 40K spectrometry by equations based on either BI or skinfold measurements in 112 healthy children, adolescents, and young adults aged 3.9 to 19.3 y. A best-fitting equation to predict TBK-derived FFM from BI and other potential independent predictors was developed and cross validated in two randomly selected subgroups of the study population by stepwise multiple regression analysis. Although the technical error associated with BI measurements was much smaller than that of skinfold measurements, the reproducibility of BI-derived FFM estimates (intraobserver coefficient of variation [CV], 0.39%; interobserver CV, 1.23%) was only slightly better than that of FFM estimates obtained by use of weight and two skinfold measurements (0.62% and 1.39%, respectively). The cross validation procedure yielded the following best-fitting prediction equation: FFM = 0.65 x (height2/impedance) + 0.68 x age + 0.15 (R2 = 0.975, root mean square error = 1.98 kg, CV = 5.8%, 95% limits of agreement = -11.1% to +12.4%). Conventional anthropometry, using published equations to estimate FFM from skinfolds, slightly over-estimated TBK-derived FFM, but predicted FFM with precision similar to the best-fitting equation involving BI. Previously published FFM equations incorporating BI predicted TBK-drived FFM with variable predictive precision and accuracy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Early rehabilitation of coma patients on the neurosurgical intensive care station. On the philosophy and practice of interdisciplinary cooperation].

The concept of early rehabilitation is an important task of humanity for neurosurgical intensive care patients emerging from coma. In Germany only little experience in this field has been reported, although the concept of early rehabilitation is well known in the other western European countries and the USA. In connection with the author's teaching activities at the pedagogical and psychological departments of the University of Oldenburg, an interdisciplinary concept of communicative "cooperative dialogues" was established for early rehabilitation, beginning in the earliest phases of coma at the neurosurgical intensive care unit. Although the results could not be evaluated statistically yet, the clinical course and outcome of emergence from primary or postoperative coma have improved rapidly by single patients, based on mobilization of neuronal plasticity and self-organized processes. Because of a significant lack of possibilities of early rehabilitation in the northwestern part of Germany, especially for young head injured adults, our efforts will continue. The philosophy and practice of early rehabilitation propose a new interpretation of neurosurgical patients emerging from coma, i.e. a dynamic process of a "second human creation". Early rehabilitation is an important task for the neurosurgically working doctor. Also for the neurosurgical profession the concept of early rehabilitation has to be integrated interdisciplinary to medical teaching at university level as soon as possible.

Activities of Daily Living↗
PubMed1989

Practical co-table for direct coronal CT scanning.

Direct coronal CT scanning can be efficiently performed by a new co-table equipment, which requires a comfortable prone positioning of the patient, whereby the patient must only extend his head slightly. The co-table-unit is linked to the original CT table board directly within a few minutes, coming through the opening of the gantry from the rear. This practical co-table method serves to reduce motion artifacts and to improve image quality significantly. By this method coronal follow-up CT scans are exactly reproducable.

Humans↗
PubMed1984

Nontraumatic intracerebellar hematomas: prognostic value of volumetric evaluation by computed tomography.

Thirty-two consecutive cases of nontraumatic intracerebellar hematomas detected by computed tomography are reviewed. A strong correlation was found between the clinical course and the volumetrically calculated size of the hematomas. Prompt evacuation has the best prognosis in cases that have an acute or subacute course (hematoma size, 22.5 to 66 cm3). Conservative treatment was most successful in chronic cases (hematoma size, 8 to 16 cm3). Surgical treatment should be the treatment of choice in very acute cases also (hematoma size, over 70 cm3) if the hematoma is diagnosed immediately after the onset of bleeding. Early detection and volumetric evaluation by computed tomography have great prognostic value for managing nontraumatic intracerebellar hematomas.

Adolescent↗
PubMed1980

Subdural hematoma associated with dural metastatic tumor.

Two cases of subdural hematoma associated with dural metastasis are reported. The computed tomographic and angiographic features are presented. The possible pathogenetic mechanism is discussed. Our cases support the idea of obstruction of dural capillaries by neoplastic cells and subsequent subdural bleeding.

Carotid Arteries↗
PubMed1979

[On relapsing paraneoplastic cerebral embolism. Case report and survey of literature (author's transl)].

The disease of a 34-year-old patient with relapsing cerebral embolisms, endocarditis, thrombophlebitis and hypercoagulopathy had the characteristics of paraneoplastic syndromes described and discussed in literature. Autopsy yielded a clinically unrecognised, dedifferentiated adenocarcinoma of the bronchial system. At an early stage of the disease cerebral embolisms had produced severe cerebral neurological signs with varying manifestations. This influenced not only the clinical picture and course of the disease to a considerable extent, but also focussed diagnostic attention on these signs to such a degree that the possibility of a masked carcinoma did not seem to suggest itself. The assumption of paraneoplastic linkups is supported by experimental and postmortem examinations on metabolic and immunological remote action of tumours on cardiac valves and on the vascular and coagulation system. However, the exact pathogenetic details are still largely unknown.

Adenocarcinoma↗