Renato Zanetti | UFMG - The Federal University of Minas Gerais (original) (raw)

Papers by Renato Zanetti

Introduction: The Perception Sensory Threshold (ST) for sinusoidal current stimuli at 5, 250, and... more Introduction: The Perception Sensory Threshold (ST) for sinusoidal current stimuli at 5, 250, and 2,000 Hz
is commonly used in the assessment of peripheral nerve fibers (C, Aδ, and Aβ, respectively). However, the
neuroselectivity of these frequencies is far from consensus. In addition, Reaction Time (RT) measurements
suggest that 2,000 Hz stimuli excite Aβ-fibers, 250 Hz Aβ- or Aδ-fibers, as well as 5 Hz Aβ-, Aδ- or C-fibers.
Therefore, we suppose that the sinusoidal current neuroselectivity may be better observed if ST and RT
parameters are jointly evaluated. In addition, we have investigated whether there are other sets of frequencies
that could be used. Methods: Thus this work investigates ST and RT for stimuli with frequency ranging from 1
to 3,000 Hz, on 28 healthy subjects aged from 19 to 44 years old (27.1 ± 5.49). ST and RT dissimilarity among
different frequencies was evaluated applying bi-dimensional Fisher Quadratic Discriminant. Results: The
lowest classification error (3.6%) was obtained for 1, 250, and 3,000 Hz. Error for 5, 250, and 2,000Hz was
16.7%. Stimulation frequency at 1 Hz evoked more sensations related to C-fibers (53% of reports) than to
Aβ-fibers (36%). However, this behavior did not repeat itself at 5 Hz (only 21% of perceptions were related
to C-fibers against 64% to Aβ-fibers). Sensations related to Aβ-fibers prevailed for the highest frequencies
presented to the subjects (2,000 Hz – 82% and 3,000 Hz – 93%). Mean RT values showed a decreasing
trend with frequency. Conclusion: These results suggest that frequencies 1, 250, and 3,000 Hz are more
neuroselective than 5, 250, and 2,000 Hz for the evaluation of peripheral sensitive fibers. Furthermore, they
show RT usefulness.

Introduction: The Perception Sensory Threshold (ST) for sinusoidal current stimuli at 5, 250, and... more Introduction: The Perception Sensory Threshold (ST) for sinusoidal current stimuli at 5, 250, and 2,000 Hz
is commonly used in the assessment of peripheral nerve fibers (C, Aδ, and Aβ, respectively). However, the
neuroselectivity of these frequencies is far from consensus. In addition, Reaction Time (RT) measurements
suggest that 2,000 Hz stimuli excite Aβ-fibers, 250 Hz Aβ- or Aδ-fibers, as well as 5 Hz Aβ-, Aδ- or C-fibers.
Therefore, we suppose that the sinusoidal current neuroselectivity may be better observed if ST and RT
parameters are jointly evaluated. In addition, we have investigated whether there are other sets of frequencies
that could be used. Methods: Thus this work investigates ST and RT for stimuli with frequency ranging from 1
to 3,000 Hz, on 28 healthy subjects aged from 19 to 44 years old (27.1 ± 5.49). ST and RT dissimilarity among
different frequencies was evaluated applying bi-dimensional Fisher Quadratic Discriminant. Results: The
lowest classification error (3.6%) was obtained for 1, 250, and 3,000 Hz. Error for 5, 250, and 2,000Hz was
16.7%. Stimulation frequency at 1 Hz evoked more sensations related to C-fibers (53% of reports) than to
Aβ-fibers (36%). However, this behavior did not repeat itself at 5 Hz (only 21% of perceptions were related
to C-fibers against 64% to Aβ-fibers). Sensations related to Aβ-fibers prevailed for the highest frequencies
presented to the subjects (2,000 Hz – 82% and 3,000 Hz – 93%). Mean RT values showed a decreasing
trend with frequency. Conclusion: These results suggest that frequencies 1, 250, and 3,000 Hz are more
neuroselective than 5, 250, and 2,000 Hz for the evaluation of peripheral sensitive fibers. Furthermore, they
show RT usefulness.