Assessment of the Olfactory Function in Patients With Idiopathic Intracranial Hypertension Using the Sniffin’ Sticks Test: A Case‐Control Study

Abstract

Objective Despite the lack of recognition in clinical practice, there is increasing evidence that patients with idiopathic intracranial hypertension may suffer from hyposmia. The current case‐control study aims to evaluate olfactory dysfunction in a large series of patients with idiopathic intracranial hypertension. Methods All subjects, 44 idiopathic intracranial hypertension patients and 57 healthy controls, underwent olfactory function assessment using standardized “Sniffin’ Sticks” test at a tertiary referral center of a university hospital. Threshold, discrimination, identification, and total threshold‐discrimination‐identification scores have been determined and analyzed statistically. Results Idiopathic intracranial hypertension patients had significantly lower threshold (6.5 [3.69] vs 8 [1.88], P < .001, 95% CI [−2.250, −0.750]) and threshold‐discrimination‐identification scores (29.75 [5.56] vs 32.5 [5.25], P = .003, 95% CI [−4.250, −0.750]). Twenty‐five patients (57%) were diagnosed with hyposmia. Test scores of patients with active idiopathic intracranial hypertension (n = 18) were not statistically different from patients with inactive disease (n = 26), except for discrimination score (14 [2.50] vs 11 [2.25], P = .005, 95% CI [−3.000, −1.000]). Although idiopathic intracranial hypertension patients with a cerebrospinal fluid opening pressure of ≥330 mmH2O had lower test scores, the difference was significant only for total threshold‐discrimination‐identification scores (28.5 [5.50] vs 30.5 [4.38], P = .044, 95% CI [0.750, 5.500]). Multiple regression analysis revealed that test scores were related to disease activity, cerebrospinal fluid opening pressure, papilledema, headache, and medication. Conclusion Our clinical study revealed significant olfactory dysfunction in patients with idiopathic intracranial hypertension compared with healthy controls. Future research should employ larger samples to search for usability of olfactory testing in clinical management of patients with idiopathic intracranial hypertension.

Stauungspapille, Pseudotumor cerebri und idiopathische intrakranielle Hypertension – Was gibt es Neues?

“…Neben dem visuellen System wurde 2008 auch eine Affektion des olfaktorischen Systems bei IIH nachgewiesen [34]. Bei 25 von 44 IIH-Patienten (57 %) wurde zuletzt in einer Fallkontrollstudie eine Hyposmie diagnostiziert, unabhängig davon, ob die Erkrankung gerade aktiv oder inaktiv war [35]. Ob das olfaktorische System jedoch von Nutzen ist für das klinische Management von IIH-Patienten, müssen größer angelegte Studien noch zeigen.…”

Association of pediatric idiopathic intracranial hypertension with olfactory performance

“…Olfactory dysfunction has been associated with some neurological [ 11 ] and psychiatric disorders [ 12 , 13 ], and its evaluation has gained increasing interest with the development of novel quantitative standardized tools. Cumulative reports have suggested an association of IIH with olfactory dysfunction in adults [ 5 , [14] , [15] , [16] ], and some authors proposed that olfactory impairment might serve as a more sensitive predictor of IIH than other clinical features [ 5 ]. However, none of the studies conducted to date included patients younger than 18 years.…”