Ability-Based Optimization of Touchscreen Interactions

Eye fixation patterns of 21 dyslexic and 21 younger, nondyslexic readers were compared when they read aloud 2 texts. The study examined whether word-frequency and word-length effects previously found for skilled adult readers would generalize equally to younger dyslexic and nondyslexic readers. Significantly longer gaze durations and reinspection times were found for low-frequency and long words than for high-frequency and short words. The effects also showed up in the number of fixations on the target words. The effects did not differ significantly for the 2 experimental groups. The results run counter to the oculomotor dysfunction hypothesis of dyslexia. Instead, they support the view that both dyslexic and nondyslexic readers' eye fixation patterns reflect their difficulties in successfully identifying words in a text.

The purpose of this investigation was to determine the effects of healthy aging on the regularity of physiological tremor under rest and postural conditions. Additionally, we examined the contribution of mechanical reflex factors to age-related changes in postural physiological tremor. Tremor regularity, tremor-electromyographic (EMG) coherence, tremor amplitude, and tremor modal frequency were calculated for 4 age groups (young: 20-30 yr, young-old: 60-69 yr, old: 70-79 yr, and old-old: 80-94 yr) under resting and loaded postural conditions. There were 6 important findings from this study: 1) there were no differences between the young and elderly subjects for any of the dependent variables measured under the rest condition; 2) postural physiological tremor regularity was increased in the elderly; 3) postural physiological tremor-EMG coherence was also increased in the elderly, and there was a strong linear relation between peak tremor-EMG coherence in the 1- to 8-Hz frequency band and regularity of tremor. This relation was primarily driven by the increased magnitude of tremor-EMG coherence at 5.85 and 6.83 Hz; 4) enhanced mechanical reflex properties were not responsible for the increased magnitude of tremor-EMG coherence in the elderly subjects; 5) tremor amplitude was not different between the 4 age groups, but there was a slight decline in tremor modal frequency in the oldest age group in the unloaded condition; and 6) despite the increases in postural physiological tremor regularity and the magnitude of low frequency tremor-EMG coherence with age, there was a clear demarcation between healthy aging and previously published findings related to tremor pathology.