Objective: Revised diagnostic criteria for idiopathic intracranial hypertension (IIH) were proposed in part to reduce misdiagnosis of intracranial hypertension without papilledema (WOP) by using 3 or 4 MRI features of intracranial hypertension when a sixth nerve palsy is absent. This study was undertaken to evaluate the sensitivity and specificity of the MRI criteria and to validate their utility for diagnosing IIH in patients with chronic headaches and elevated opening pressure (CH + EOP), but WOP. Methods: Brain MRIs from 80 patients with IIH with papilledema (WP), 33 patients with CH + EOP, and 70 control patients with infrequent episodic migraine were assessed in a masked fashion for MRI features of intracranial hypertension. Results: Reduced pituitary gland height was moderately sensitive for IIH WP (80%) but had low specificity (64%). Increased optic nerve sheath diameter was less sensitive (51%) and only moderately specific (83%). Flattening of the posterior globe was highly specific (97%) but had low sensitivity (57%). Transverse venous sinus stenosis was moderately sensitive for IIH WP (78%) but of undetermined specificity. A combination of any 3 of 4 MRI features was nearly 100% specific, while maintaining a sensitivity of 64%. Of patients with CH + EOP, 30% had 3 or more MRI features, suggesting IIH WOP in those patients. Conclusion: A combination of any 3 of 4 MRI features is highly specific for intracranial hypertension and suggests IIH WOP when present in patients with chronic headache and no papilledema.

Background and Purpose: Previous work demonstrates that older adults have a lower response in the middle cerebral artery velocity (MCAv) to an acute bout of moderate intensity exercise when compared to young adults. However, no information exists regarding MCAv response to exercise post-stroke. We tested whether MCAv response to an acute bout of moderate intensity exercise differed between participants 3 months post-stroke and an age-and sex-matched control group of older adults (CON). A secondary objective was to compare MCAv response between the stroke and non-stroke affected MCAv. Methods: Using transcranial Doppler ultrasound, we recorded MCAv during a 90-second baseline (BL) followed by a 6-minute moderate intensity exercise bout using a recumbent stepper. Heart rate (HR), end tidal CO2 (PETCO2) and beat-to-beat mean arterial blood pressure (MAP) were additional variables of interest. The MCAv response measures included: BL, peak response amplitude (Amp), time delay (TD), and time constant (τ). Results: The Amp was significantly lower in the stroke affected MCAv compared to CON (p < 0.01) and in the non-affected MCAv and compared to CON (p = 0.03). No between-group differences were found between TD and τ. No significant differences were found during exercise for PETCO2, and MAP while HR was lower in participants with stroke. (p < 0.01). Within the group of participants with stroke, no differences were found between the stroke-affected and non-stroke affected side for any measures. Discussion and Conclusions: Resolution of the dynamic response profile has the potential to increase our understanding of the cerebrovascular control mechanisms and test cerebrovascular response to physical therapy driven interventions such as exercise. Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1).

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