R2C is the most sensitive parameter in the blink reflex, which can help in the diagnosis of subclinical diabetic cranial neuropathy.

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Background: About 39-59% of individuals with idiopathic intracranial hypertension (IIH) have cranial nerve impairments of some kind, including single or multiple cranial nerve (CN) palsies. Objective: The aim of the current study was to assess clinical outcome after cerebrospinal fluid (CSF) tapping through blink reflex (BR). Patients and methods: A comparative study was carried out on 40 female patients with IIH, aged between 18 and 60 years, and 40 age and sex matched normal volunteers as a control group, between 2019 and 2021. Participants were subjected to blink reflex before and after therapeutic CSF tapping at Neuro-Diagnostic & Research Center (NDRC), Beni-Suef University Hospital. Results: Patients with IIH after CSF tapping showed significant decrease of latencies of BR {the ipsilateral R2 (R2i) from 31.6 (2.8) to 30.6 (2.1) ms (P=0.019) and contralateral R2 (R2c) from 35.2 (3.3) to 33.8 (2.5) ms (P=0.023). After CSF tapping, when compared patients to controls, the latencies of R2i 30.6 (2.1) to 29 (2.6) ms (P=0.005) and R2c 33.8 (2.5) to 32.2 (2.8) ms (P=0.007). Conclusion:The therapeutic CSF tapping improves latencies of R2i and R2c of BR and clinical outcome IIH.

The goal of our study was to clarify the possible effect of increased intracranial pressure on electrophysiological blink reflex in idiopathic intracranial hypertension (IIH) pateints . Subjects & Methods: 40 females;20 IIH patients and 20 age matched controls , after through neurological examination , were subjected to electrically elicited blink reflex (BR) . Results: There was a significant delay in ipsilatral R2 (R2i) and contralateral R2 (R2c) latencies with 31.6 (±2.8) msec and 35.2 (±3.3) msec among cases when compared to controls with 29 (±2.6) msec and 32.2 (±2.8) msec respectively with (P-value<0.001), while R1 latencies were 10.4(±1) msec in cases and 10.5(±0.6) in controls with no signifcant difference between the two groups (p-value=0.726) Conclusion: the increased intracranial pressure was proved to increase R2i and R2c latencies of blink reflex studies which may suggest subclinical facial nerve dysfunction in IIH patients whether through peripheral nerve compression or at the level of the reflex centers (lateral medullla)in IIH patients.

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 15ṁ 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.