Assessment of amblyopic children undergoing occlusion therapy by pattern visual evoked potentials and contrast sensitivity tests.

Background: Amblyopia is a case where one or less commonly, both eyes have impaired visual performance, even with the best optical correction and no visible disease of the visual system. Objectives: To assess contrast sensitivity tests (CST) and pattern visual evoked potentials (PVEP) results in amblyopic children who have already started occlusion therapy for durations ranging from 6 to 12 months. Methods: This cross-sectional study was conducted on 200 eyes of 50 patients with monocular amblyopia and 50 age and sex matched controls. Both patients and controls underwent ophthalmological assessment, PVEP, and CST. Results: There was no statistically significant difference in the results of P100 latencies of qualitative PVEP in amblyopic eyes compared to non-amblyopic eyes and control eyes, while the qualitative CST showed a highly statistically significant difference, being affected in 98% of amblyopic eyes compared to unaffected eyes (4%) and control eyes (4%). The maximum contrast level and minimal contrast level of quantitative CST were significantly lower in amblyopic eyes compared to non-amblyopic and control eyes. The cutoff value of maximal contrast level at mean frequencies of 2.5 ± 0.9 Hz, and a range of (1.1-4.1) for amblyopic eyes is ≤21 dB, while the cutoff value of minimal contrast level at mean frequencies of 13.4 ± 2.6 Hz, and a range of (6.7-18) for amblyopic eyes is ≤12 dB. Conclusion: Detection of amblyopia by CST is a noninvasive and easy procedure, which represents a promising tool to support the diagnosis of amblyopia.

Role of pattern electroretinogram in assessment of retinal dysfunction in hypertensive patients.

BACKGROUND: Hypertension is a major health problem in both developing and developed countries. Hypertension causes retinal structural and functional impairment within the ganglion cell layer. Pattern electroretinogram (PERG) offers an objective simple tool for assessment of retinal ganglion cell function.Aim of the work: To assess retinal dysfunction in hypertensive patients with or without signs of retinopathy using PERG. MATERIALS AND METHODS: This is a case control study, including ninety-eight eyes. Twenty-eight eyes of healthy subjects served as a control group (group I) and seventy eyes of patients with systemic hypertension, who were further subdivided into group II including 39 eyes of hypertensive patients with normal fundus and group III including 31 eyes of patients with signs of hypertensive retinopathy. All subjects were subjected to ophthalmological examination and electrophysiological assessment using PERG. RESULTS: PERG implicit times were significantly prolonged and amplitudes were significantly reduced in patients with established hypertensive retinopathy. PERG abnormalities were detected in 96.8% of hypertensive retinopathy patients and 79.5% of hypertensive patients with normal fundus. CONCLUSIONS: PERG can objectively assess retinal dysfunction in hypertensive patients and may be considered a promising tool for early detection of hypertensive retinopathy.

Role of multifocal electroretinogram in assessment of early retinal dysfunction in hypertensive patients.

PURPOSE: To investigate localized retinal dysfunction in hypertensive patients using multifocal electroretinogram (mfERG) and to assess its sensitivity as an early predictor for the development of retinopathy in hypertensive patients. METHODS: Ninety-eight eyes were included in this case-control study. Twenty-eight eyes of healthy subjects served as a control group (group I). Seventy eyes belonged to patients with systemic hypertension assigned into two groups; group II including 39 eyes of hypertensive patients with normal fundus and group III including 31 eyes of patients with signs of hypertensive retinopathy. All participants were subjected to complete ophthalmic and electrophysiological examination using mfERG. N1 and P1 wave amplitudes and implicit times from the central hexagon and four concentric rings across the visual field were analyzed. RESULTS: mfERG amplitudes were significantly reduced in hypertensive group with retinopathy than in controls. N1 amplitude was significantly reduced in the most eccentric ring in eyes of hypertensive patients with normal fundus. CONCLUSION: mfERG is a sensitive objective tool for assessment of retinal dysfunction in hypertensive patients. mfERG amplitude is a promising predictor for early development of retinopathy in systemic hypertension.

Sleep disorders in children and adolescents on regular hemodialysis.

Sleep disorders in children with chronic kidney disease have been assessed in a limited number of studies. Our aim was to characterize the types of sleep disorders in children on regular hemodialysis and to detect the predictors of sleep efficiency in those children. Forty children and adolescents on regular hemodialysis and another 40 age- and gender-matched control groups were interviewed to answer a questionnaire-based survey, a modified Epworth Sleepiness Scale, to assess excess daytime sleepiness. Also, they underwent an overnight in-laboratory polysomnography to assess total sleep time, sleep efficiency, sleep staging, apnea/hypopnea index, and periodic limb movement index. We found poor sleep efficiency in 20% of cases, and periodic limb movement index higher than 5 in 45%, and apnea/hypopnea index higher than 5 in 40%. There was significant negative correlation between sleep efficiency on one hand, and serum potassium, serum creatinine, and sleep onset on other hand (p < 0.001, p < 0.001, and p < 0.001, respectively). There was significant decrease in hemoglobin, serum iron, and transferrin saturation in patients with excess daytime sleepiness (p < 0.001, p = 0.003, and p = 0.010, respectively). By using multivariate linear regression analysis, we found that serum creatinine was the single independent predictor of sleep efficiency.Conclusion: Poor sleep quality is not uncommon in hemodialysis children. Our results show a lower frequency of sleep disorders in comparison with previous studies. There is a strong association between kidney dysfunction and poor sleep quality in HD children.What is known:• Sleep disturbances can adversely affect a child's daytime performance.• Sleep disorders in children with chronic kidney disease have been assessed in only a limited number of studies.What is new:• Poor sleep quality is not uncommon in hemodialysis children.• There is a strong association between kidney dysfunction and poor sleep quality in hemodialysis children.

Electrophysiological Assessment of the Impact of Mobile Phone Radiation on Cognition in Persons With Epilepsy.

PURPOSE: Serious concerns about the effect of mobile phone radiation on cognition are growing. This study aimed to assess the possible effect of mobile phone radiation in persons with epilepsy and in normal subjects. METHODS: The amplitude and reaction time of auditory event-related potentials (P300) and occipital alpha frequency were compared before and after exposure with a 30-minute call in 30 persons with epilepsy and in 30 control subjects. Alpha power was monitored before, during, and after exposure to mobile phone radiation. Moreover, correlations with clinical aspects were analyzed. RESULTS: Increased reaction time and decreased P300 amplitude were more evident in persons with epilepsy. A significant decrease in alpha power was noted in control subjects and persons with epilepsy and was associated with an increased bilateral alpha frequency. In persons with epilepsy, such changes significantly correlated with the time since the last seizure and with the therapy regimen. CONCLUSIONS: Thirty-minute exposure to mobile phone radiation has a significant effect on the electrophysiological correlates of cognition, especially in persons with epilepsy.

Role of concentric needle Single Fiber Electromyography in detection of subclinical motor involvement in carpal tunnel syndrome.

BACKGROUND: Conventional motor nerve conduction studies are usually normal in early and mild carpal tunnel syndrome (CTS). Single-fiber electromyography (SFEMG) measures the mean consecutive difference (MCD) as an expression of the variability in impulse transmission over the motor endplates and along the nerve fibers distally to the last branching point and along the muscle fibers.Application of concentric needle SFEMG in a group of CTS patients who showed pure sensory abnormalities in nerve conduction studies to examine for subclinical motor involvement. METHODS: Thirty CTS patients having only sensory involvement proved clinically and by conventional electrophysiological studies were included in addition to 30 control subjects. Concentric needle SFEMG was performed to the abductor pollicis brevis (APB), abductor digiti minimi (ADM), and extensor digitorum communis (EDC) muscles. RESULTS: There was a statistically significant difference in the MCD between the patient and control groups in the APB only (p = 0.038). CONCLUSIONS: The results suggest the presence of a subclinical motor median neuropathy at the wrist in patients with early and mild carpal tunnel syndrome and highlight the validity of the concentric needle SFEMG in early neuropathies. TRIAL REGISTRATION: PACTR201802002971380 registered 12 February 2018, retrospectively registered.

Axonal degeneration of the ulnar nerve secondary to carpal tunnel syndrome: fact or fiction?

The distribution of sensory symptoms in carpal tunnel syndrome is strongly dependent on the degree of electrophysiological dysfunction of the median nerve. The association between carpal tunnel syndrome and ulnar nerve entrapment is still unclear. In this study, we measured ulnar nerve function in 82 patients with carpal tunnel syndrome. The patients were divided into group I with minimal carpal tunnel syndrome (n = 35) and group II with mild to moderate carpal tunnel syndrome (n = 47) according to electrophysiological data. Sixty-one age- and sex-matched subjects without carpal tunnel syndrome were used as a control group. There were no significant differences in ulnar sensory nerve peak latencies or conduction velocities from the 4(th) and 5(th) fingers between patients with carpal tunnel syndrome and the control group. The ulnar sensory nerve action potential amplitudes from the 4(th) and 5(th) fingers were lower in patients with carpal tunnel syndrome than in the control group. The ratios of the ulnar sensory nerve action potential amplitudes from the 4(th) and 5(th) fingers were almost the same in patients with carpal tunnel syndrome as in the control group. These findings indicate that in patients with minimal to moderate carpal tunnel syndrome, there is some electrophysiological evidence of traction on the adjacent ulnar nerve fibers. The findings do not indicate axonal degeneration of the ulnar nerve.