Association of pediatric idiopathic intracranial hypertension with olfactory performance

To assess the association between pediatric Idiopathic intracranial hypertension (IIH) and olfactory performance.

A cross-sectional comparative study was conducted including 17 patients under 18 years diagnosed with IIH at a tertiary hospital and 17 healthy age- and sex-matched subjects. All participants underwent the semi-objective chemosensory Sniffin' Sticks test for evaluation of odor threshold (OT), indicative of peripheral olfactory function, and odor identification (OI), reflecting higher cognitive olfactory processing. Scores were compared and referred to the updated normative values. Demographic, clinical, and neuroimaging data were collected from the medical files. The patients with IIH were reassessed for olfactory function and clinical state at the subsequent follow-up, under treatment.

Compared to controls, the IIH group had a significantly lower mean OT score (6.41 ± 3.43 vs 10.21 ± 2.79, p = 0.001) and higher rate of OT score below the 10th percentile for age and sex according to the normative values (47.1% vs 0%, p = 0.001). There was no significant between-group difference in mean OI scores (9.82 ± 1.63, vs 10.59 ± 1.84, p = 0.290). OT scores were not associated with sex, age, body mass index, neuroimaging abnormalities, or lumbar puncture opening pressure. At the follow-up assessment, the OT scores were improved (9.36 ± 4.17 vs 6.7 ± 3.32, p = 0.027) whereas the OI scores were unchanged (9.88 ± 2.5 vs 9.69 ± 1.58, p = 0.432).

As reported in adults, children and adolescents with IIH appear to have a selective reversible deficit in olfactory detection threshold, which may imply a reduction in peripheral olfactory perceptual ability. Future studies should examine the predictive value of olfactory function for IIH.