Integrating eye tracking in virtual reality for stroke rehabilitation

This thesis reports on research done for the integration of eye tracking technology into virtual reality environments, with the goal of using it in rehabilitation of patients who suffered from stroke. For the last few years, eye tracking has been a focus on medical research, used as an assistive tool  to help people with disabilities interact with new technologies  and as an assessment tool  to track the eye gaze during computer interactions. However, tracking more complex gaze behaviors and relating them to motor deficits in people with disabilities is an area that has not been fully explored, therefore it became the focal point of this research. During the research, two exploratory studies were performed in which eye tracking technology was integrated in the context of a newly created virtual reality task to assess the impact of stroke. Using an eye tracking device and a custom virtual task, the system developed is able to monitor the eye gaze pattern changes over time in patients with stroke, as well as allowing their eye gaze to function as an input for the task. Based on neuroscientific hypotheses of upper limb motor control, the studies aimed at verifying the differences in gaze patterns during the observation and execution of the virtual goal-oriented task in stroke patients (N=10), and also to assess normal gaze behavior in healthy participants (N=20). Results were found consistent and supported the hypotheses formulated, showing that eye gaze could be used as a valid assessment tool on these patients. However, the findings of this first exploratory approach are limited in order to fully understand the effect of stroke on eye gaze behavior. Therefore, a novel model-driven paradigm is proposed to further understand the relation between the neuronal mechanisms underlying goal-oriented actions and eye gaze behavior.

The influence of sour taste and cold temperature in pharyngeal transit duration in patients with stroke

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stroke in ancient times - a reinterpretation of Psalms 137 : 5,6

Stroke was probably first described in Psalms 136: 5-6 of the Catholic Bible, and Psalms 137:5-6 of the Evangelical Bible. Based on the Portuguese, Spanish, English, German, Dutch, Russian, Greek, and original Hebrew Bible, the significance of this Psalm is the invocation of a punishment, of which the final result would be a stroke of the left middle cerebral artery, causing motor aphasia and right hemiparesis.

Gait training with partial body weight support during overground walking for individuals with chronic stroke: a pilot study

Background: It is not yet established if the use of body weight support (BWS) systems for gait training is effective per se or if it is the combination of BWS and treadmill that improves the locomotion of individuals with gait impairment. This study investigated the effects of gait training on ground level with partial BWS in individuals with stroke during overground walking with no BWS.Methods: Twelve individuals with chronic stroke (53.17 +/- 7.52 years old) participated of a gait training program with BWS during overground walking, and were evaluated before and after the gait training period. In both evaluations, individuals were videotaped walking at a self-selected comfortable speed with no BWS. Measurements were obtained for mean walking speed, step length, stride length and speed, toe-clearance, durations of total double stance and single-limb support, and minimum and maximum foot, shank, thigh, and trunk segmental angles.Results: After gait training, individuals walked faster, with symmetrical steps, longer and faster strides, and increased toe-clearance. Also, they displayed increased rotation of foot, shank, thigh, and trunk segmental angles on both sides of the body. However, the duration of single-limb support remained asymmetrical between each side of the body after gait training.Conclusions: Gait training individuals with chronic stroke with BWS during overground walking improved walking in terms of temporal-spatial parameters and segmental angles. This training strategy might be adopted as a safe, specific and promising strategy for gait rehabilitation after stroke.

Physiological and Stroke Parameters to Assess Aerobic Capacity in Swimming

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of gender on stroke rates, critical speed and velocity of a 30-min swim in young swimmers

Our objective was to analyze the effect of gender on the relationship between stroke rates corresponding to critical speed (SRCS) and maximal speed of 30 min (SRS30) in young swimmers. Twenty two males (GM1) (Age = 15.4 ± 2.1 yr., Body mass = 63.7 ± 12.9 kg, Stature = 1.73 ± 0.09 m) and fourteen female (GF) swimmers (Age = 15.1 ± 1.6 yr., Body mass = 58.3 ± 8.8 kg, Stature = 1.65 ± 0.06 m) were studied. A subset of males (GM2) was matched to the GF by their velocity for a 30 min swim (S30). The critical speed (CS) was determined through the slope of the linear regression line between the distances (200 and 400 m) and participant's respective times. CS was significantly higher than S30 in males (GM1 - 1.25 and 1.16 and GM2 - 1.21 and 1.12 m·s-1) and females (GF - 1.15 and 1.11 m·s-1). There was no significant difference between SRCS and SRS30 in males (GM1 - 34.16 and 32.32 and GM2 - 34.67 and 32.46 cycle·s-1, respectively) and females (GF - 34.18 and 33.67 cycle·s-1-1, respectively). There was a significant correlation between CS and S30 (GM1 - r = 0.89, GF - r = 0.94 and GM2 - r = 0.90) and between SRCS and SRS30 (GM1 - r = 0.89, GF - r = 0.80 and GM2 - r = 0.88). Thus, the relationship between SRCS and SRS30 is not influenced by gender, in swimmers with similar and different aerobic capacity levels. ©Journal of Sports Science and Medicine (2007).

Economics of climate change in Latin America and the Caribbean: summary 2009

Includes bibliography

The United States and Latin America and the Caribbean: Highlights of economics and trade

Foreword by Alicia Bárcena