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In case of presbyopia or cataract the "artificial accommodation system" represents one future possibility to durably restore the ability to accommodate. The work presented describes recent progress in the development of the artificial accommodation system. Major advances were achieved in the fields of the actuator system for the active optics, the pupil near reflex sensor, the communication system, the power supply system as well as in system integration. Beside the technical advances, first trials were performed to implant the artificial accommodation system into animals. These trials showed that the new lens shaped design and the C-shaped haptics are beneficial for implantation and secure fixation of the implant inside the capsular bag.

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Obstructive sleep apnea (OSA) is a sleep disorder with a high prevalence that causes pathological changes in cardiovascular regulation during the night and also during daytime. We investigated whether the treatment of OSA at night by means of continuous positive airway pressure (CPAP) improves the daytime consequences. Twenty-eight patients with OSA, 18 with arterial hypertension, 10 with normal blood pressure, were investigated at baseline and with three months of CPAP treatment. Ten age and sex matched healthy control subjects were investigated for comparisons. We recorded a resting period with 20min quiet breathing and an exercise stress test during daytime with ECG and blood pressure (Portapres). The bicycle ergometry showed a significant reduction of the diastolic blood pressure at a work load of 50W and 100W (p<0.05 and p<0.01, respectively) and a decrease of the heart rate recovery time after the stress test (p<0.05). These results indicate a reduction of vascular resistance and sympathetic activity during daytime. The coupling analysis of the resting periods by means of symbolic coupling traces approach indicated an effect of the CPAP therapy on the baroreflex reaction in hypertensive patients where influences of the systolic blood pressure on the heart rate changed from pathological patterns to adaptive mechanisms of the normotensive patients (p<0.05).

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BACKGROUND: Confocal laser scanning microscopy (CLSM) allows the in vivo analysis of nerve structures of the human cornea. In this way, pathological alterations of the peripheral nervous system that also affect the corneal subbasal nerve plexus (SNP) can be diagnosed non-invasively and possibly earlier than with other methods. The field of view of in vivo CLSM images of the cornea (ca. 0.4 × 0.4 mm²) is not sufficient for a reliable assessment. Two phenomena make the image assessment difficult: the presence of ridge-like tissue deformations in the neighbourhood of the SNP and image distortions that are induced by involuntary and unavoidable eye movements during image acquisition. This paper presents an image processing method for generating undistorted images of the SNP with an extended field of view. METHODS: The presented method has been tested on five volunteers. Eight focus image stacks have been taken and processed from each subject using a Heidelberg Retina Tomograph with Rostock Cornea Module (HRT). An image registration scheme specifically adapted to the image acquisition system corrects the non-linear motion-induced image distortions and reconstructs a volume from each focus image stack. The epithelial basal boundary surface including the SNP appears as a distinctive hyper-reflective layer inside the reconstructed volume. Extracting this continuous layer generates a depth map and finally a two-dimensional image of the SNP. A final fusion step of the single reconstructed SNP images leads to laterally extended images. RESULTS: Out of 40 focus image stacks, 34 have been fully processed into two-dimensional SNP reconstruction images. Six focus image stacks could not be transformed into volumes because of extremely fast eye movements during the image acquisition that prevented the complete image registration of the stacks. The 34 SNP reconstruction images depict an average area of 94.7 % ( ±â€Š6.2 %) with respect to the field of view of a single HRT image. The final fusion of the reconstructed images resulted in an average increase of the image area by a factor of 2.6 (ranging from 2.2 to 3.1). CONCLUSION: The presented image processing algorithms are capable of correcting the motion-induced image distortions and of generating larger two-dimensional images of the SNP even in presence of severe tissue deformations. These images provide the basis for a more reliable assessment of the corneal nerve fibres.

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Directional coupling analysis of time series is an important subject of current research. In this paper, a method based on symbolic dynamics for the detection of time-delayed coupling in biosignals is presented. The symbolic coupling traces, defined as the symmetric and diametric traces of the bivariate word distribution, allow for a more reliable quantification of coupling and are compared with established methods like mutual information and cross recurrence analysis. The symbolic coupling traces method is applied to appropriate model systems and cardiological data which demonstrate its advantages especially for nonstationary and noisy data. Moreover, the method of symbolic coupling traces is used to analyze and quantify time-delayed coupling of cardiovascular measurements during different sleep stages. Significant different regulatory mechanisms are detected not only between the deep sleep and the other sleep stages but also between healthy subjects and patients. The proposed method may help to indicate pathological changes in cardiovascular regulation and also effects of continuous positive airway pressure therapy on the cardiovascular system.

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Sleep is a physiological process with an internal program of a number of well defined sleep stages and intermediate wakefulness periods. The sleep stages do modulate the autonomous nervous system and thereby the sleep stages are accompanied by different regulation regimes for the cardiovascular and respiratory system. The differences in regulation can be distinguished by new analysis techniques on the recorded signals. In addition to normal sleep regulation some sleep disorders affect the cardiovascular and respiratory regulation. The most prevalent disorder linked to sleep and changes in the autonomous system is obstructive sleep apnea. In patients with obstructive sleep apnea marked short term changes in cardiovascular and respiratory regulation are observed during sleep. These abnormalities in regulation are further differentiated between the sleep stages. For long term changes obstructive sleep apnea is recognized as a major risk factor for arterial hypertension. Treatment of obstructive sleep apnea lowers blood pressure during the night and over time also lowers blood pressure during daytime. In this study we investigated 18 patients with sleep apnea and normal blood pressure, 10 patients with sleep apnea and arterial hypertension and 10 normal subjects as controls. Both patient groups were tested with cardiorespiratory polysomnography before and under CPAP therapy. The effects on cardiovascular and respiratory regulation during sleep and daytime are investigated in the three groups.

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Age-related ailments like presbyopia and cataract are increasing concerns in the aging society. Both go along with a loss of ability to accommodate. A new approach to restore the patients' ability to accommodate is the Artificial Accommodation System. This micro mechatronic system will be implanted into the capsular bag to replace the human crystalline lens. Depending on the patients' actual need for accommodation, the Artificial Accommodation System autonomously adapts the refractive power of its integrated optical element in a way that the projection on the patients' retina results in a sharp image. As the Artificial Accommodation System is an active implant, its subsystems have to be supplied with electrical energy. Evolving technologies, like energy harvesting, which can potentially be used to power an implant like the Artificial Accommodation System are at the current state of art not sufficient to power the Artificial Accommodation System autonomously [1]. In the near future, therefore an inductive power supply system will be developed which includes an energy storage to power the Artificial Accommodation System autonomously over a period of 24 h and can be recharged wirelessly. This Paper describes a new possibility to optimize the secondary coil design in a solely analytical way, based on a new figure of merit. Within this paper the developed figure of merit is applied to optimize the secondary coil design for the Artificial Accommodation System.

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Presbyopia and cataract are gaining more and more importance in the ageing society. Both age-related complaints are accompanied with a loss of the eye's ability to accommodate. A new approach to restore accommodation is the Artificial Accommodation System, an autonomous micro system, which will be implanted into the capsular bag instead of a rigid intraocular lens. The Artificial Accommodation System will, depending on the actual demand for accommodation, autonomously adapt the refractive power of its integrated optical element. One possibility to measure the demand for accommodation non-intrusively is to analyse eye movements. We present an efficient algorithm, based on the CORDIC technique, to calculate the demand for accommodation from magnetic field sensor data. It can be shown that specialised algorithms significantly shorten calculation time without violating precision requirements. Additionally, a communication strategy for the wireless exchange of sensor data between the implants of the left and right eye is introduced. The strategy allows for a one-sided calculation of the demand for accommodation, resulting in an overall reduction of calculation time by 50 %. The presented methods enable autonomous microsystems, such as the Artificial Accommodation System, to save significant amounts of energy, leading to extended autonomous run-times.

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In this paper a new approach for restoring human accommodation is presented. It is an artificial accommodation system based on the latest results of microtechnology, electronics and automatic control. The concept of the overall system is described and the results obtained for the different subsystems are discussed.

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In order to restore the ability of accommodation of the human eye, a lens implant manufactured by micro system technology can be used. This highly integrated Artificial Accommodation System contains sensitive electronics as well as moving components in order to adapt its refractive power. One challenge of the production of this system is the encapsulation. It has to be a biocompatible and long-term reliable package. In this paper the advantages of a hermetic glass package over other approaches of encapsulation are introduced. Concepts of production for a glass package are presented. The package is thereby optimised to be placed in the optical path of the eye, but it can also be used for the encapsulation of other implants.

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Sleep is a complex regulated process with short periods of wakefulness and different sleep stages. These sleep stages modulate autonomous functions such as blood pressure and heart rate. The method of symbolic coupling traces (SCT) is used to analyze and quantify time-delayed coupling of these measurements during different sleep stages. The symbolic coupling traces, defined as the symmetric and diametric traces of the bivariate word distribution matrix, allow the quantification of time-delayed coupling. In this paper, the method is applied to heart rate and systolic blood pressure time series during different sleep stages for healthy controls as well as for normotensive and hypertensive patients with sleep apneas. Using the SCT, significant different cardiovascular mechanisms not only between the deep sleep and the other sleep stages but also between healthy subjects and patients can be revealed. The SCT method is applied to model systems, compared with established methods, such as cross correlation, mutual information, and cross recurrence analysis and demonstrates its advantages especially for nonstationary physiological data. As a result, SCT proves to be more specific in detecting delays of directional interactions than standard coupling analysis methods and yields additional information which cannot be measured by standard parameters of heart rate and blood pressure variability. The proposed method may help to indicate the pathological changes in cardiovascular regulation and also the effects of continuous positive airway pressure therapy on the cardiovascular system.

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The parameters of heart rate variability and blood pressure variability have proved to be useful analytical tools in cardiovascular physics and medicine. Model-based analysis of these variabilities additionally leads to new prognostic information about mechanisms behind regulations in the cardiovascular system. In this paper, we analyze the complex interaction between heart rate, systolic blood pressure, and respiration by nonparametric fitted nonlinear additive autoregressive models with external inputs. Therefore, we consider measurements of healthy persons and patients suffering from obstructive sleep apnea syndrome (OSAS), with and without hypertension. It is shown that the proposed nonlinear models are capable of describing short-term fluctuations in heart rate as well as systolic blood pressure significantly better than similar linear ones, which confirms the assumption of nonlinear controlled heart rate and blood pressure. Furthermore, the comparison of the nonlinear and linear approaches reveals that the heart rate and blood pressure variability in healthy subjects is caused by a higher level of noise as well as nonlinearity than in patients suffering from OSAS. The residue analysis points at a further source of heart rate and blood pressure variability in healthy subjects, in addition to heart rate, systolic blood pressure, and respiration. Comparison of the nonlinear models within and among the different groups of subjects suggests the ability to discriminate the cohorts that could lead to a stratification of hypertension risk in OSAS patients.

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In the paper, a new adaptive hand prosthesis developed in the Institute of Applied Computer Sciences of the Forschungszentrum Karlsruhe is described. Starting from the state-of-the-art, the requirements of the hand prosthesis are derived and the realisation of the new prosthesis is shown. Finally the results obtained are discussed.

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BACKGROUND: Use of an implantable mechatronic microsystem (artificial accommodation system) is a novel approach to restoration of the accommodative capacity of the human eye. One such system, based on the triple-optic approach, has been selected for investigation of its suitability. METHODS: Optical modelling of the dioptric apparatus is carried out by means of an optical simulation tool. Postoperative refractive compensation plus at least 3 dpt of accommodation are required. RESULTS: An axial shift of 300 microm or less is achieved for the entire range of biometric data ascertained before surgery. In addition, the defined requirements made of optical imaging quality are met. CONCLUSIONS: The triple-optic approach is basically suitable for application in the restoration of accommodative capacity. It seems that flexure hinges could be used in association with conducting polymers as actuator material. One question that is still open concerns the deformability of such implants as this relates to minimally invasive corneal incisions.

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A new experimental hand prosthesis design is presented that differs from that of conventional prostheses. With the objective of addressing consumers' requirements, functionality was increased and cosmetic appearance became more natural. By integrating a hydraulic system with 8 small fluidic actuators at the digit joints, different important grasping patterns of everyday life can be performed. These are: power grasp, hook grasp, precision grasp, lateral pinch, and a posture to operate a keyboard with the extended index. As a result of multi-articulation and the inherent compliancy of the actuators, objects can be grasped adaptively. Moreover, a vibrotactile feedback system makes the prosthesis controllable without visual attention. For a more natural appearance, the hand is covered by a cosmetic silicone rubber glove. The hands are designed for performing activities of everyday life, including office work. The new hand design can help closing the gap between purely cosmetic hands and functional hands.

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