Developmental stuttering is a speech disorder in fluency characterized by repetitions, prolongations, and silent blocks, especially in the initial parts of utterances. Although their symptoms are motor related, people who stutter show abnormal patterns of cerebral hemispheric dominance in both anterior and posterior language areas. It is unknown whether the abnormal functional lateralization in the posterior language area starts during childhood or emerges as a consequence of many years of stuttering. In order to address this issue, we measured the lateralization of hemodynamic responses in the auditory cortex during auditory speech processing in adults and children who stutter, including preschoolers, with near-infrared spectroscopy. We used the analysis–resynthesis technique to prepare two types of stimuli: (i) a phonemic contrast embedded in Japanese spoken words (/itta/ vs. /itte/) and (ii) a prosodic contrast (/itta/ vs. /itta?/). In the baseline blocks, only /itta/ tokens were presented. In phonemic contrast blocks, /itta/ and /itte/ tokens were presented pseudo-randomly, and /itta/ and /itta?/ tokens in prosodic contrast blocks. In adults and children who do not stutter, there was a clear left-hemispheric advantage for the phonemic contrast compared to the prosodic contrast. Adults and children who stutter, however, showed no significant difference between the two stimulus conditions. A subject-by-subject analysis revealed that not a single subject who stutters showed a left advantage in the phonemic contrast over the prosodic contrast condition. These results indicate that the functional lateralization for auditory speech processing is in disarray among those who stutter, even at preschool age. These results shed light on the neural pathophysiology of developmental stuttering.

Forty stutterers and 40 nonstutterers were tested for susceptibility to delayed auditory feedback (DAF) while reading passages under amplified delay conditions. Susceptibility to DAF of stutterers was significantly higher than that of nonstutterers. In the nonstuttering group, men were more susceptible to DAF than women, but in the stuttering group, there was no significant difference between sexes. There was also no significant difference in DAF susceptibility between stuttering men and nonstuttering men. Nonstuttering women were least susceptible to DAF. A Susceptibility Index (SI) was found to discriminate speaker sensitivity to DAF and was interpreted to suggest that stutterers rely on auditory feedback for speech control more than nonstutterers.

Left unilateral spatial neglect in mild to moderate AD may be rather common if tested with the line bisection test. Rightward errors over 10 mm suggest right temporoparietal dysfunction. In AD, three or more bisections of 200 mm lines in the center presentation are recommended for detection of neglect. Patients with AD but without neglect may have difficulty in shifting attention into the peripheral sector of the egocentric space.

The purpose of this study is to examine the variability in sensory test of tactile results using Semmes-Weinstein monofilament (SWM). At present, several methods for measuring the tactile sensitivity are clinically used in diabetic peripheral neuropathy screening. One of these methods is a touch test that uses a device with nylon SWMs, i.e., SWMs embedded in a plastic handle. A small pushing force is applied at the handle to bow the filaments. Because of its ease and simplicity, the SWM test is conducted at the patient's bedside in a hospital. However, previous studies have reported some problems with this test. Studies have shown variations in the measured data, and it is uncertain whether these variations are caused by mechanical properties of the nylon fiber or by the motion of the operator's hands. We carried out two experiments to examine the effect of (1) the variability caused by the human operator conducting the SWM test on the test results and (2) the number of compressions of the SWM on the test results. In experiment 1, we measured the velocity of the operator's hand motion and the buckling force of the SWMs. The results showed variability in the hand motion of the operator conducting the SWM tests. In experiment 2, we measured the buckling force of the SWMs under a controlled velocity. We compared the buckling force of the SWMs through a number of trials. These results showed that the buckling force gradually decreases as the number of test cycles increase. In conclusion, we find that the accuracy of the SWM tests is a factor of the number of test cycles. Additionally, manual training for standardizing skills of medical staff members needs to be developed. Furthermore, the characteristics of the SWMs deteriorated over time. In future work, we aimto find a solution to minimize the variability in the SWM test results and develop a new testing system that uses tactile sensibility for diabetic peripheral neuropathy screening.

The purpose of this study is to develop smart equipment to quantify plantar tactile sensibility for early diagnosis and tracking of peripheral neuropathy caused by diabetes mellitus. In this paper, we present new testing equipment composed of a plantar tactile stimulation platform with a moving contactor to stretch the skin tangentially, a response switch for each tactile stimulus, a motor control box, and a personal computer for psychophysical data processing. This testing equipment offers more precise measurements and is easy to use compared to conventional testing tools such as von Frey monofilaments, pin-prick testing devices, and current perception threshold testers. Using our testing equipment, we showed that the plantar tactile threshold for the tangential stretching stimulus on the first metatarsal head of the feet ranges from approximately 10 to 60 μm for subjects without diabetic foot problems. Meanwhile, the plantar tactile threshold of some subjects suspected of having diminished protective sensation by the Semmens-Weinstein monofilament testing is approximately 100 μm or more. These preliminary results suggest that our testing equipment based on the plantar sensation elicited by lateral stretching of skin has the potential for quantitative diagnosis in subjects suspected of suffering from neuropathy, and for monitoring changes over time to sustain quality of life.