Cognitive function and quantitative electroencephalogram analysis in subjects recovered from COVID-19 infection.

BACKGROUND & OBJECTIVES: Objective assessment of post-COVID-19 cognitive dysfunction is highly warranted. This study aimed to evaluate the cognitive dysfunction of COVID-19 survivors with cognitive complaints, both clinically and neurophysiologically, using Quantitative Electroencephalogram (QEEG). METHODS: This case-control study was conducted on 50 recovered subjects from COVID-19 infection with cognitive complaints and 50 age, sex, and educational-matched healthy controls. Both groups were subjected to the following neurocognitive tests: Paired associate learning Test (PALT) and Paced Auditory Serial Addition Test (PASAT). The neurophysiological assessment was also done for both groups using QEEG. RESULTS: COVID-19 survivors had significantly lower PALT scores than controls (P < 0.001). QEEG analysis found significantly higher levels of Theta / Beta ratio in both central and parietal areas in patients than in the controls (P < 0.001 for each). The interhemispheric coherence for the frontal, central, and parietal regions was also significantly lower in patients than in the control group regarding alpha and beta bands. There were statistically significant lower scores of PALT and PASAT among cases with severe COVID-19 infection (P = 0.011, 0.005, respectively) and those who needed oxygen support (P = 0.04, 0.01, respectively). On the other hand, a statistically significantly lower mean of frontal alpha inter-hemispheric coherence among patients with severe COVID-19 infection (P = 0.01) and those needing mechanical ventilation support (P = 0.04). CONCLUSION: Episodic memory deficit is evident in COVID-19 survivors with subjective cognitive complaints accompanied by lower inter-hemispheric coherence in frontal regions. These clinical and neurophysiological changes are associated with hypoxia and COVID-19 severity.

Neurophysiological visual assessment in patients with idiopathic intracranial hypertension: visual evoked potential and multifocal field electroretinography.

BACKGROUND: Determining the cause of visual deterioration in idiopathic intracranial hypertension (IIH) patients is of clinical necessity. This study aimed to study the effect of chronic increased ICP on the retina and optic nerve through objective electrophysiological measures in chronic IIH patients. METHODS: Thirty patients with chronic IIH and thirty age and sex-matched healthy controls were included in this study. Papilledema grade and CSF pressure were evaluated in the patients' group. Both groups were submitted to visual evoked potentials (VEP) and multifocal electroretinogram (mfERG). RESULT: The mean value of P100 latencies of the right and left on two check sizes, 1 deg and 15m in chronic IIH patients, was significantly delayed than controls (P-value < 0.001 for each). Chronic IIH patients showed a significantly lower amplitude of the right and left R1, R2, R3, R4 & R5 compared to controls (P-value < 0.001, < 0.001) (P-value < 0.001, < 0.001) (P-value < 0.001, < 0.001) (P-value < 0.001, = 0.001) (P-value = 0.002, < 0.001), respectively. Also, patients showed a significantly delayed peak time of the right and left R1 and R2 compared to controls (P-value < 0.001, < 0.001) (P-value = 0.001, = 0.009), respectively. There was a significant positive correlation between each of CSF pressure and papilledema grade with right and left PVEP latencies. In contrast, there was no statistically significant correlation between either CSF pressure or papilledema grade and PVEP amplitudes in both eyes. CONCLUSION: In chronic IIH patients, both optic nerve dysfunction and central retinal changes were identified, supported by VEP and the mfERG findings.

Effect of Biofeedback Corrective Exercise on Reaction Time and Central Somatosensory Conduction Time in Patients With Forward Head Posture and Radiculopathy: A Randomized Controlled Study.

Objective: The purpose of this study was to examine the effect of 8 weeks of biofeedback on reaction time and central somatosensory conduction time in patients with forward head posture and cervical radiculopathy. Methods: We performed a double-blinded randomized controlled trial. Seventy patients with forward head posture and cervical radiculopathy were randomly distributed into study and control groups. The study group received biofeedback forward head posture corrective exercise for 8 weeks, while the control group did not receive any treatment. The main outcome measures were reaction time and central somatosensory conduction time. The secondary outcome measures were the craniovertebral angles, nerve conduction time at N13 and N20, referred arm pain, and neck disability index. Results: After 4 weeks, there were nonsignificant differences between both groups in reaction time and central somatosensory conduction time (P > .05); while there were significant differences between both groups in N13, N20, craniovertebral angle, referred arm pain, and neck disability index scores (P < .05). After 8 weeks, there were significant differences between both groups in all outcome measures (P < .05). Conclusion: In this study, participants receiving biofeedback forward head posture corrective exercise improved both reaction time and central somatosensory conduction time after 8 weeks when compared to a control, nontreatment group.

Blink reflex in type 2 diabetes mellitus.

PURPOSE: An evaluation of the extent of damage of the central nervous system in diabetes mellitus is of high value in current research. Electrophysiological abnormalities are frequently present in asymptomatic patients with diabetes mellitus. Diabetic cranial neuropathy is one of the complications of the disease. Blink reflex is used to diagnose subclinical cranial neuropathy. The objective is to test the utility of blink reflex in detecting subclinical cranial nerve involvement in patients with type 2 diabetes mellitus. METHODS: Forty patients with type 2 diabetes mellitus, aged from 30 to 60 years examined clinically and neurologically. Blink reflex and nerve conduction studies for the upper and lower limbs were performed and compared with 20 matched normal controls. RESULTS: Diabetic patients with peripheral neuropathy showed significant prolonged distal latency and reduced amplitudes of the R2C response compared with the control, patients without peripheral neuropathy showed insignificant changes. Alteration of R2 correlated with the type of treatment and the duration of the disease. In patients without peripheral neuropathy, ulnar sensory distal latencies showed significant positive correlation with R2I latency, whereas its Conduction Velocity (CV) showed significant positive correlation with R2C amplitudes and negative correlation with R2C latency. CONCLUSIONS: R2C is the most sensitive parameter in the blink reflex, which can help in the diagnosis of subclinical diabetic cranial neuropathy.