The Effect of Refractive Error Correction on Stereopsis

Purpose: The present study aimed to assess the effect of refractive error (RE) correction on stereopsis. Materials and Methods: A total of 62 participants underwent comprehensive ophthalmic examinations, which included measurements of visual acuity, RE, stereopsis, ocular alignment, as well as examinations of the anterior and posterior ocular segments. Stereopsis was evaluated using the TNO random dot stereogram booklet at a distance of 33cm, both with and without RE correction. The results were then compared to evaluate the impact of RE correction on stereopsis. Results: Our findings revealed that correcting one diopter of the spherical and spherical equivalent components of RE led to a significant improvement in stereopsis, with improvements of 30.884 and 30.373 seconds of arc, respectively (P = 0.001). However, the correction of other components of RE did not demonstrate a statistically significant effect on improving stereopsis. Additionally, we found no significant correlation between different types and severities of refractive errors and stereopsis. Conclusion: Correcting the spherical and spherical equivalent components of refractive error may enhance stereopsis across various types of refractive errors

Effect of Transcranial Direct Current Stimulation on Auditory-Verbal Memory in Healthy Elderly

Background and purpose: Auditory-verbal memory decreases with age. One method to compensate this weakness is transcranial direct current stimulation. The current study investigated the effect of Anodal Transcranial Direct Current Stimulation on auditory-verbal memory performance of healthy elderly people. Materials and methods: In a randomized clinical trial, 42 healthy subjects with no history of cognitive problems were divided into experimental and control groups (n=21 per group). All participants received 10 sessions of electrical stimulation at 2 mA. In order to evaluate the auditory-verbal memory of the subjects, the Persian version of the Rey Auditory Verbal Learning Test (RAVLT) was used before and after electrical current delivery. Results: In experimental group, the mean scores for all stages of the RAVLT, were found to be significantly different after electrical stimulation compared to those before stimulation (P<0.05). Also, the mean scores for all stages of the RAVLT showed significant differences between the control group and experimental group after electrical stimulation (P< 0.05) except in the reminder stage after the intervention (P= 0.075).  Conclusion: Anodal Transcranial Direct Current Stimulation affects the electrical potential of nerve cells membrane in the dorsolateral prefrontal cortex (DLPFC) and increases neural activity of nerve cells in that area, which can lead to improvements in auditory-verbal memory

The Relationship between Sensory Processing Disorder and Quality of Sleep in Children with Autism Spectrum Disorder and Learning Disorder from 6 to 14 Years' Old

Introduction: Sensory problems can affect the functioning of individuals in a variety of daily activities in different aspects. One of these aspects of daily activity is the quality and quantity of sleep. Sensory processing perhaps is the most basic psychological element that determine how individuals perceive and respond to environmental stimuli. Given this, this study aimed to investigate the effect of sensory processing disorder on sleep quality of children with autism spectrum disorder and learning disorder. Materials and Methods: The present study was a descriptive cross-sectional study. The study was performed on 23 children with autism spectrum disorder and 20 children with learning disorder from 6 to 14 years' old. Two Child Sleep Habits Quality (CSHQ) and Sensory profile 2 questionnaires were used for data collection. Data were analyzed by Mann-Whitney U test in SPSS 22 software. Results: The results of data analysis showed that children with ASD have lower sleep quality than children with specific learning disorder (P=0/033). Children with autism also received higher scores on sensory profile 2 subtests except visual and olfactory processing than children with specific learning disorders. In children with ASD the highest scores are related to Sensory Sensitivity (45.83) and sensory registration (45.17) and lowest score is related to visual processing (10.96). However, children with specific learning disorders have highest score in sensory registration (43.40) and lowest score in body position processing (8.55). Conclusion: The findings of the study emphasized children with poor sleep quality had sensory processing disorder and sleep quality were reduced. There was a significant relationship between sensory registration (P=0.005) and sensory sensitivity (P=0.012) with sleep quality. Therefore, it seems necessary to support children in considering proper sensory diet and taking measures to resolve their sensory problems and thus improve their sleep patterns. Keywords: Autism Spectrum Disorder; Learning Disorder; Quality of Sleep; Sensory Processing Disorde

Comparing human electrocochleography responses to click and chirp stimuli

Background and Aim: It is not known how electrocochleography components of action potentials (AP) and summating potentials (SP) are changed in response to CE-chirp stimulus using extra-tympanic electrodes. This study was done for comparing summating potentials and action potentials specifications in response to CE-chirp and click stimuli.Methods: Electrocochleography components of action potentials and summating potentials were recorded in 16 normal hearing subjects (8 men and 8 women) aged 22-30 years (mean: 26.7 with SD 2.5 years) with audiometric (250-8000 Hz) hearing thresholds of 15 dB HL or better in response to click and CE-chirp stimulus at 90 dB nHL. Amplitude, duration, latency and area of summating potentials and action potentials and SP/AP amplitude and area ratios were compared.Results: Among the measured parameters, action potentials amplitude in response to CE-chirp stimulus (0.41 with SD 0.26 µV ) was significantly smaller than action potentials amplitude in response to click (0.61 with SD 0.29 µV ) stimulus (p<0.005). Relative frequency of detecting summating potentials in response to CE-chirp (68.7%) was lower than (100%) click (p<0.005).Conclusion: Recording electrocochleography component of summating potentials and action potentials with CE-chirp stimulus at high intensity level in normal hearing individuals shows no advantage over click stimulus. Small amplitude of summating potentials as a major problem of extra-tympanic electrocochleography cannot be solved using CE-chirp stimulus