ABSTRACT
We investigated the level of hearing tolerance in patients with first-episode psychosis (FEP) and panic disorder (PD) as compared to two different groups of healthy controls (HC, HC2), one for each experiment, because we used two distinct psychophysical paradigms. We evaluated auditory discomfort of 28 volunteers (14 with FEP and 14 HC) in the first study and of 42 volunteers (21 with PD and 21 HC2) in the second study. We presented 20 sounds: 16 pure-tone frequency sweeps (specially designed for use with FEP) and 11 s or 13 s musical sequences from the very beginning of the music "Play the Game" (PLAY) from Queen and its reverses. The first procedure used a Likert-like 0-10 scale ranging from "nothing bad" to "too bad" where volunteers made vertical marks along a horizontal line according to their discomfort. The second procedure involved subjective magnitude estimation online due to the SARS-COV-19 pandemic. Sounds were placed online and played by PD and HC2 volunteers themselves after having listened to the standard (the first 8 s from RADIO, "Radio Ga Ga" by Queen). Then, PD and HC2 volunteers were asked to assign values equal to, or multiples of 10 that felt like, or proportional to, their hearing "discomfort" in comparison with Sound 00 (RADIO). Our findings showed that FEP volunteers assign more discomfort to the 16 specially designed frequency sweep stimuli that appear not to affect HC, HC2, and PD. On the other hand, musical sequences from PLAY caused strong discomfort to PD in the reverse mode, but did not seem to affect HC, HC2, and FEP. Further experiments using the exact same paradigm with FEP and PD are needed to explore these findings.
ABSTRACT
Awareness of perceptual and sensory changes that might occur in visual, auditory, proprioception, and other senses, in the early stages towards the First Episode Psychosis (FEP), and their subsequent sensorial evolution as the disturb progresses deeper into an acute episode, might be a key element for interrupting the process. In the present study, we investigated hearing discomfort/tolerance to 16 given sound streams. Sixteen people diagnosed with FEP, participated in the experiment. Sixteen frequency sweeps varying in modulation envelopes (sawtooth, sine), order (ascending, descending), duration (4s, 8s), and range (50-8000 Hz, 2-8 kHz) were presented randomly, but always in the same sequence, to FEP and healthy controls (HC). The level of discomfort was estimated by the participant by making a mark across a continuous line whose extremes read "nothing bad" (left) and "too bad" (right). Results showed that ascending sine pure frequency sweeps (p < 0.01) and descending sine pure frequencies sweeps (p < 0.01) caused the maximum discomfort in FEP. Other variables also showed differences between FEP and HC, and FEP were always more intolerant to such pure frequency sweeps than HC. We conclude that this might be useful for very early assessment of people at risk, people with FEP, and people with schizophrenia.
ABSTRACT
In this study, we compared visual pictorial size perception between healthy volunteers (CG) and an experimental group (EG) of people diagnosed with schizophrenia. We have been using paintings by Salvador Dalí and Rorschach plates to estimate visual pictorial size perception. In this transversal, ex post facto, and quasi-experimental study, we observed differences between EG and CG. Schizophrenic in-patients perceived sizes about 1.3-fold greater than healthy volunteers (p=0.006), implying that pictorial size perception is altered in some way in schizophrenia. Considering the present and previous results, this measurement of diameter size of first pictorial perception may be a useful estimate of some aspects of perceptual alterations that may be associated with psychotic symptoms in prodromal and acute schizophrenic episodes and other related mental states. Eventually, this may help in preventing people from evolving to acute episodes.
ABSTRACT
Previous studies have shown that multiple sclerosis (MS) affects the visual system, mainly by reducing contrast sensitivity (CS), a function that can be assessed by measuring contrast sensitivity function (CSF). To this end, we measured both the CSF for sine-wave gratings and angular frequency stimuli with 20 participants aged between 21 and 44 years, of both genders, with normal or corrected to normal visual acuity. Of these 20 participants, there were 10 volunteers with clinically defined MS of the relapsing-remitting clinical form, with no history of optic neuritis (ON), as well as 10 healthy volunteers who served as the control group (CG). We used a forced-choice detection paradigm. The results showed reduced CS to both classes of stimuli. Differences were found for sine-wave gratings at spatial frequencies of 0.5, 1.25, and 2.5 cycles per degree (cpd) (P < 0.002) and for angular frequency stimuli of 4, 24, and 48 cycles/360° (P < 0.05). On the one hand, comparing the maxima of the respective CSFs, the CS to angular frequency stimuli (24 cycles/360°) was 1.61-fold higher than that of the CS to vertical sine-wave gratings (4.0 cpd) in the CG; for the MS group, these values were 1.55-fold higher. On the other hand, CS in the MS group attained only 75% for 24 cycles/360° and 78% for 4.0 cpd of the 100% CS estimates found for the CG at the peak frequencies. These findings suggest that MS affects the visual system, mostly at its maximum contrast sensitivities. Also, since angular frequencies and sine-wave gratings operate at distinct levels of contrast in the visual system, MS seems to affect CS at both high and low levels of contrast.