Stroke Trajectory Research Articles

Model-based analysis of Chinese calligraphy images

A lot of research and development have been done on producing Chinese fonts with smooth outlines and solid colouring for computer displays and printing. Existing Chinese fonts however are not able to reproduce or convey the aesthetic properties of the characters produced by calligraphers. Ip and Wong proposed a parameterised brush model called the Virtual Brush, which enables efficient representation and generation of Chinese calligraphic writings such that the rendering is scalable in resolution and allows high quality publishing. While other researchers always focus on synthesis, we are working as a pioneer on the reverse problem— calligraphic image analysis. Given a static calligraphic image, it is a labour-intensive task to construct a set of 3-D geometric and writing model parameters to obtain a dynamic representation. It is therefore desirable to develop an automated approach to estimate the Virtual Brush parameters from images of Chinese calligraphy. This paper describes a methodology of a statistical-based approach with image processing techniques for the automatic estimation of the set of Virtual Brush writing parameters, such as the properties of brush hair and variations of ink deposition along a stroke trajectory, directly from an image of calligraphic writing. With our proposed approach, raw digitalised images of Chinese calligraphic writings could be analysed automatically for storage and subsequent synthesis for high quality publishing of Chinese characters in different styles and calligraphic artwork.

The clinical outcomes of neonatal and childhood stroke: review of the literature and implications for future research.

A detailed assessment of clinical outcomes after ischemic stroke in childhood is necessary to evaluate prognostic factors. Previous studies are difficult to compare because of differences in test instruments, study design, heterogeneity of cohorts and number of included cases. Depending on neurodevelopmental assessment methods, major and subtle/minor disabilities, especially in infants, may not have been detected. Most outcome studies reveal only limited information about behavioral changes and quality of life in children with ischemic stroke. Thus the assumption that children make a better recovery from stroke than adults due to the immature brain's capacity to reorganize function is not evidence-based. We systematically review the current literature with regard to the neurological and psychosocial development of affected children as well as their quality of life. Implications for future research strategies follow the review to encourage further clinical study of the neurobehavioral trajectory of childhood stroke.

The unfolding illness trajectory of stroke

Purpose: To describe the characteristics of the illness trajectory of stroke during the first year. Method: A qualitative, prospective case study design; repeated in-depth semi-structured interviews with nine mild to moderately affected stroke patients during the course of the first year. A total of 63 interviews were conducted. The interview data were transcribed verbatim and analysed as a text, using a hermeneutic approach. Results: A stroke is not necessarily experienced as an abrupt psychosocial crisis by the stroke patient. The adjustment process seems to be gradually evolving and prolonged over most of the first year following the cerebro-vascular accident (CVA). The illness trajectory may be divided into four phases, each with characteristic tasks and focal points. The adjustment process involves hard physical and psychosocial work on the part of patient. A necessary pre-requisite for adjustment is a realistic conception of the illness and its implications. This takes time and experience to achieve. Conclusions: The adjustment process following stroke is gradual and prolonged. In order to move away from the predominant functional rehabilitation approach towards a more comprehensive and better targeted service, increased understanding of the complexities of the adjustment process is necessary.

Family caregiver expectations and management of the stroke trajectory.

Less than 20% of stroke survivors enter rehabilitation or long-term care facilities after their stroke. Stroke recovery is extremely variable and the resulting uncertainty places a heavy burden on the survivors' family caregivers. According to the trajectory framework, chronic conditions have a defined course that can be shaped and managed. This grounded theory study, part of a larger research project, explored the expectations of family caregivers of the stroke trajectory and their management strategies. Thirteen family caregivers of stroke patients in a sparsely populated area participated in semi-structured interviews. The caregivers were without ideas about what the recovery of their loved ones would be like and had difficulty making projections about the trajectory. They used several strategies, however, in attempts to manage the stroke trajectory. They constructed a positive recovery, reconstituted family life, maintained family routines, created a safety net, and redoubled self-reliance. The findings have implications for how nurses support family caregivers of stroke survivors.

Virtual brush: a model-based synthesis of Chinese calligraphy

This paper describes the Virtual Brush, a model-based approach to synthesizing realistically Chinese calligraphic writings. This approach simulates the physical process of brush stroke creation using a parameterized model which captures (a) the writing brush 3D geometric parameters, (b) the brush hair properties and (c) the variations of ink deposition along a stroke trajectory. An analysis of some well-known Chinese brush writing styles is given, with a view to establishing the relationship of these writing styles and the modeling process of simulating these different writing styles. We present here our model formulation and the implementation of a software which is capable of simulating some typical calligraphic writing styles on a PC platform. This parameterized model allows a compact representation for brush-written characters which can be used to synthesize characters at different levels of detail, with various brush effects. The result is applicable for very high-quality publishing purpose. Additionally, by appropriately transforming and scaling the stroke trajectories which define a virtual brush character, this technique can be used as a novel approach for scalable font design and generation, in comparison with traditional vector fonts or imaging techniques. More interestingly, with suitable interfacing techniques Virtual Brush would allow users to “practice” calligraphy electronically.

Spousal interactions in alzheimer's disease and stroke caregiving: Relationship to care recipients' functional abilities and physical and emotional health*1

Background : Previous research suggests that the quantity and quality of interactions between caregivers and care recipients have an impact on health outcomes of ill persons. Building on the work of Bowlby (1988) and Wright, Hickey, Buckwalter, and Clipp (1995) , spousal interactions are conceptualized as adult attachment; it is argued that this attachment provides protective functions for ill spouses. Objectives : Our objectives in this study were to examine spousal interactions along two divergent illness trajectories, Alzheimer's disease (AD) and stroke, and to relate time 1 spousal interactions to care recipients' time 2 functional abilities and physical and emotional health. Study Design : This longitudinal pilot study compared 42 couples (84 spouses) equally divided between early phase AD, 12 weeks after stroke, and healthy controls. Baseline (time 1) data and 6-month follow-up data (time 2) were collected in home interviews. Measures included spousal interactions and illness characteristics of persons with AD and recipients of care after a stroke. Results : AD couples reported lower quantity and quality of interactions compared with stroke couples. Spousal interactions were positively correlated to physical and emotional health in AD care recipients and to functional abilities in stroke care recipients. Only AD care recipients' interactions were related to depression. Conclusions : Spousal interactions along the AD trajectory represented the protective function of attachment; along the stroke trajectory, reciprocal adult exchanges continued.

Spousal Interactions in Alzheimer's Disease and Stroke Caregiving: Relationship to Care Recipients' Functional Abilities and Physical and Emotional Health

BACKGROUND: Previous research suggests that the quantity and quality of interactions between caregivers and care recipients have an impact on health outcomes of ill per sons. Building on the work of Bowlby (1988) and Wright, Hickey, Buckwalter, and Clipp (1995), spousal interactions are conceptualized as adult attachment; it is argued that this attachment provides protective functions for ill spouses. OBJECTIVES: Our objectives in this study were to examine spousal interactions along two diver gent illness trajectories, Alzheimer's disease (AD) and stroke, and to relate time 1 spousal interactions to care recipients' time 2 functional abilities and physical and emotional health. STUDY DESIGN: This longitudinal pilot study compared 42 couples (84 spouses) equally divided between early phase AD, 12 weeks after stroke, and healthy controls. Baseline (time 1) data and 6-month follow-up data (time 2) were collected in home interviews. Measures included spousal interactions and illness characteristics of persons with AD and recipients of care after a stroke. RESULTS: AD couples reported lower quantity and quality of interactions compared with stroke couples. Spousal interactions were positively correlated to physical and emo tional health in AD care recipients and to functional abilities in stroke care recipients. Only AD care recipients' interactions were related to depression. CONCLUSIONS: Spousal interactions along the AD trajectory represented the protective function of attachment; along the stroke trajectory, reciprocal adult exchanges contin ued. (J Am Psychiatr Nurses Assoc [1998]. 4, 169-181)

Neural encoding of shape: responses of cutaneous mechanoreceptors to a wavy surface stroked across the monkey fingerpad.

1. The role of cutaneous mechanoreceptors in the tactile perception of shape was investigated. Objects whose surfaces were shaped as a pattern of smooth, alternating convex and concave cylindrical surfaces of differing radii of curvature were constructed such that there were no discontinuities in the slope of the surface. These "wavy surfaces" were stroked across the fingerpad of the anesthetized monkey and electrophysiological responses of slowly adapting type I mechanoreceptive afferents (SAs) and rapidly adapting type I mechanoreceptive afferents (RAs) were recorded. 2. For both SAs and RAs, each convexity indenting the skin evoked a burst of impulses and each concavity of the same curvature that followed elicited a pause in response. "Spatial event plots" (SEPs) of the occurrence of action potentials as a function of the location of the object on the receptive field were obtained and interpreted as the responses of a spatially distributed population of fibers. With increasing magnitude of curvature (equivalently, decreasing radius of curvature) of convexity, the mean width of the burst in the SEPs for each fiber type (representing the width of a region of skin containing active fibers) decreased and the mean discharge rate during the burst increased. Over a range of velocities of stroking from 1 to 40 mm/s, the number of RAs activated increased with velocity, whereas SAs were active at all velocities. For both SAs and RAs, the burst rates increased with velocity, whereas the widths of the bursts and pauses remained approximately invariant. Thus the spatial measures of burst or pause width provide a robust representation of the size of a feature on the object surface. 3. For a given velocity of stroking, the spatially distributed pattern of averaged discharge rates (spatial rate profile, SRP) provided a representation of the shape of the wavy surface. The distance between neighboring peaks in the SRP for individual RAs and SAs was approximately the same as the distance between the peaks of the wavy surface. The averaged SRP for a population of SAs provided a better representation of shape than that for RAs. Whereas active regions in the SEP can be isomorphic to the two dimensional form of the stimulus "footprint" in contact with the skin surface, the SRP, which in addition encodes the features of the stimulus in the third dimension normal to the skin surface, is not isomorphic to the stimulus shape. 4. When the sizes as well as the shapes of objects are varied, it is hypothesized that a central processing mechanism extracts the invariant property of shape from the slopes of the rising and falling phases of an SRP that has been normalized for overall differences in discharge rates. These differences would be expected to occur with variations in the parameters of stimulation such as compressional force, stroke trajectory, and stroke velocity. It was shown that a common feature of the mean SRP for SAs evoked by each wavy surface convexity, regardless of its radius, was the constancy of the slope from the base to the peak and from the peak to the base. Thus a possible code for the constant curvature of a cylinder is the constancy of the slopes along the rising and declining phases of the triangular-shaped spatial response profile evoked in the SA population by the cylindrical convexity.

Managing an Uncertain Illness Trajectory in Old Age: Patients' and Physicians' Views of Stroke

Uncertainty is a central feature of a chronic illness trajectory, resulting from questions about the effects of the illness on daily life, what symptoms mean, and what the future holds. When chronic illness occurs late in life, uncertainty is magnified, and serious questions arise about whether the individual will be able to weather the disruption and go on with daily life. This article examines illness trajectories from two vantage points, that of older persons who have had a stroke and that of physicians who care for stroke patients, by means of interviews with 36 persons who had strokes and with 20 physicians. Physicians' views of stroke were informed not only by knowledge of physiological processes but also by biomedical ideologies and cultural meanings associated with their patients' ages and impairments. People who had strokes focused on recovery; they assumed the trajectory was open to manipulation if they worked hard enough. The vague medical response to uncertainty affected patients' interpretations; what they were not told shaped their expectations about recovery as much as what they were told. The uncertain trajectory of stroke in old age is one example of how illness experience is affected by cultural attitudes about age, biomedical ideologies, the provision of health care services, and economically driven health policies. The anticipation of recovery by persons who have had strokes and the letdown when recovery does not occur reflect critical dilemmas in biomedicine and in society itself that have implications for health policy.

Oriental character font design by a structured composition of stroke elements

Oriental characters (such as Chinese, Korean, and Japanese characters) are composed of several strokes, and the shape of each stroke is determined by a brush sweep. In the paper, a new representation scheme is proposed for the design of stroke-structured fonts. This approach (called a structured composition of stroke elements) reflects the characteristics of oriental characters; each character is constructed as a set of strokes, and each stroke is represented by primitive features called stroke elements. Since the construction of an exact brush sweep is computationally quite expensive, we suggest a simple approximation method. The outlines of stroke pens are used to represent the starting, ending, and bending of a stroke. The positions of seed pens are interpolated to generate the skeleton curve of a stroke trajectory. The outline of each stroke is generated automatically from the stroke elements. The boundary of each character is constructed by merging these stroke outlines. This approach has various advantages: the font design becomes much simpler, the necessary storage space is greatly reduced, and the font variation becomes much more flexible.

Expressive brush strokes

Expressive brush strokes are modeled using a technique based on variable offset approximation of uniform cubic B-splines. The trajectory of a brush stroke is represented as a 3D cubic B-spline and each bristle as a 3D offset cubic B-spline of this trajectory. The first two coordinates are the spatial position coordinates and the third coordinate represents the shade of each bristle. This technique facilitates the process of inputting data, simplifies the computation task, and provides some advantages in the animation process of brush strokes.