Hamlet Suarez

Auditory Learning and Adaptation after Cochlear Implantation: A Preliminary Study of Discrimination and Labeling of Vowel Sounds by Cochlear Implant Users

This study examined two possible reasons underlying longitudinal increases in vowel identification by cochlear implant users: improved labeling of vowel sounds and improved electrode discrimination. The Multidimensional Phoneme Identification (MPI) model was used to obtain ceiling estimates of vowel identification for each subject, given his/her electrode discrimination skills. Vowel identification scores were initially lower than the ceiling estimates, but they gradually approached them over the first few months post-implant. Taken together, the present results suggest that improved labeling is the main mechanism explaining post-implant increases in vowel identification.This study examined two possible reasons underlying longitudinal increases in vowel identification by cochlear implant users: improved labeling of vowel sounds and improved electrode discrimination. The Multidimensional Phoneme Identification (MPI) model was used to obtain ceiling estimates of vowel identification for each subject, given his/her electrode discrimination skills. Vowel identification scores were initially lower than the ceiling estimates, but they gradually approached them over the first few months post-implant. Taken together, the present results suggest that improved labeling is the main mechanism explaining post-implant increases in vowel identification.

Postural response characterization in elderly patients with bilateral vestibular hypofunction

Abstract Conclusions: The measurement of the energy consumption (EC) of the bodys center of pressure (COP) to maintain the upright stance position was higher in elderly patients with bilateral vestibular hypofunction (BVH) compared with a control group and may be a valid parameter in the assessment of balance disorders. Objective: The aim of the study was to evaluate the energy consumption of the COP in elderly patients with BVH. Methods: The COP was recorded on a force platform (FP) for eight elderly patients with BVH related to aging and eight normal control group subjects. The EC of the COP was calculated using the discrete wavelet transform. The two groups were tested in standing position on the FP in three sensory conditions:1, eyes open; 2, eyes closed; and 3, standing on a foam pad placed on the force platform. Wilcoxons rank test and multi-factor analysis of variance were used, with the level of significance set at 0.05. Results: BVH patients showed higher values of EC of the COP signal measured in arbitrary units compared with the control group (conditions 1 and 2). None of the BVH patients could perform the test in condition 3. BVH patients had increased EC in the frequency band between 0.1 and 0.78 Hz when the visual information was canceled (condition 2).

Design and construction of a prototype system for gait analysis for research in subjects with balance problems

This work presents the design and construction of a prototype of a distributed system for gait analysis with the aim in helping diagnosis and rehabilitation treatment of elderly population with balance disorders. A suitable set of requirements for the recording and subsequent analysis of the human gait parameters were defined. The prototype should be able to record the movements of the body where it is placed, transmit the acquired data and work with complete autonomy during the time it takes to make records. The prototype was built on a PCB of reduced weight and dimensions. It was tested and compared with a commercial device and the results were satisfactory.

Vibrotactile aid and brain cortical activity.

Six profoundly deaf patients were studied with mapping evoked potentials (MEP) using an acoustic signal passed through the vibrotactile prosthesis. This stimulus produced an activation of the central sulcus brain cortex. When the proSthesis was placed in the presenternal area it showed N1 P1 potentials with higher voltage and a more defined cortical dipole inversion than when the prosthesis was placed in the arm or abdomen: thus the presternal stimulation is considered an adequate place for the use of vibrotactile stimulation. The MEP were recorded in 2 patients after a period of audiological training and they showed new earlier potentials. These suggest plastic changes in the processing of an acoustic signal sent from the presternal skin by the somatosensory pathway after training and involving learning procedures.