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.

Obstructive sleep apnea in epilepsy: a preliminary Egyptian study.

PURPOSE: The extent and clinical relevance of the association between epilepsy and sleep apnea are not previously studied in Egypt. What we wanted to know was the frequency of sleep apnea in Egyptian children with epilepsy and its influence on seizure frequency, other seizure characteristics, sleep complaint, and architecture. METHODS: All patients with epilepsy, aged up to 18 years, who underwent polysomnography were studied. Patients with any neurological disease apart from epilepsy, with psychiatric illness, had hypnotics, or sedatives or those with liver or kidney failure were excluded from the study. The patients were divided into two subgroups according to apnea/hypopnea index: group (1) patients without obstructive sleep apnea (OSA) and group (2) patients with OSA. For control group, we choose 12 healthy individuals, with age and sex matched to that of our patients. We studied the clinical characteristics of epilepsy, sleep history, and polysomnographic recording of the patients with epilepsy and the control. EEG digital and video monitoring was done for all patients. RESULTS: Eleven patients (42.3%) were found to have obstructive sleep apnea. Seizure frequency was significantly higher in the patients with OSA. Apart from apnea and hypopnea indices, all other sleep parameters did not differ between patients' subgroups. Hypopnea index in REM positively correlates with number of awaking. Apnea index in REM positively correlates with latency to deep sleep and to periodic leg movement. CONCLUSIONS AND RECOMMENDATIONS: Sleep apnea is frequent in patients with epilepsy. OSA may contribute to increase seizure frequency. We recommend investigating sleep apnea in all patients with epilepsy.

Trans-orbital sonography versus visual evoked potentials in acute demyelinating optic neuritis.

Optic neuritis (ON) is an inflammatory demyelinating condition that causes acute - usually monocular - visual loss. It is highly associated with multiple sclerosis (MS). In general, ON is a clinical diagnosis based upon the history and examination findings. OBJECTIVE: The aim was to assess the diagnostic accuracy of measuring optic nerve sheath diameter (ONSD) by ultrasound in acute optic neuritis. METHODS: This is a prospective observational study with matched controls carried out on 25 patients and 25 controls. All patients presented with first attack of an acute demyelinating ON. Both patients and controls were submitted to clinical assessment, pattern and flash visual evoked potential and trans-orbital sonography (TOS) to measure the optic nerve sheath diameter (ONSD). RESULTS: The ONSD was significantly thicker in patients with unilateral (0.6 ± 0.05 cm) and bilateral (0.6 ± 0.1 cm) optic neuritis compared to controls (0.52 ± 0.06 cm). P-value was < 0.001 and 0.04 respectively, with a cutoff value 0.57 cm. A significant negative correlation was found between the thickness of the ONSD and the visual acuity (r= -0.613, P-value <0.05). No correlation was found between the age of the patients and ONSD or between ONSD and latency of P-VEP. TOS showed 68% sensitivity and 88% specificity in diagnosing cases of ON. CONCLUSION: ONSD measured by TOS is a noninvasive, inexpensive bed-side test, which represent a supporting tool to confirm the clinical diagnosis of ON. Yet its sensitivity and specificity are lower than P-VEP.

Somatosensory Evoked Potentials as a Stand-Alone Tool During Spine Surgery: An Egyptian Preliminary Report.

PURPOSE: Monitoring of somatosensory evoked potentials (SSEPs) serves as an early warning system to detect spinal cord injury and is correlated with postoperative sensory findings. It is an indirect indicator of motor function. This study aimed to evaluate the usefulness of intraoperative SSEPs monitoring as a stand-alone tool during spinal surgeries when motor evoked potentials are not available, to prevent and predict new postoperative neurologic deficits. Motor evoked potentials were not used as the equipment needed to record them was not available at the time of this study. METHODS: This study included 50 patients, aged 14 to 67 years, undergoing extramedullary manipulations, decompression of an epidural abscess or neoplasm, removal of intramedullary tumor, or arteriovenous malformation or spine correction procedures. Somatosensory evoked potentials were analyzed for latency and peak-to-peak amplitude. Critical SSEP changes were defined as a 50% decrease in amplitude or a 10% increase in latency. RESULTS: Somatosensory evoked potentials had an overall sensitivity of 81.8%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 91.3%. CONCLUSIONS: Intraoperative SSEPs have proved to be highly sensitive and specific for iatrogenic injury, mechanical stress caused by cord traction/compression, dural traction, lowered systemic blood pressure, and cord hypothermia. The reversibility of intraoperative SSEP changes showed a highly significant relation to the number of cases with new postoperative deficits as well as type and site of pathologic study (P = 0.00, P = 0.01, and P = 0.00, respectively) but not with the level of pathologic study (P = 0.49).