title: Unilateral olfactory sensitivity in multiple sclerosis.
abstract: It is not known whether lateralized olfactory sensitivity deficits are present in MS. Since projections from the olfactory bulb to the olfactory cortex are largely ipsilateral, and since both functional imaging and psychophysical studies suggest that the right side of the brain may be more involved in olfactory processing than the left, we addressed this issue by administering well-validated tests of odor detection, along with tests of odor identification, to each side of the nose of 73 MS patients and 73 age-, gender-, and race-matched normal controls. We also determined, in 63 of the MS patients, whether correlations were present between the olfactory test measures and MRI-determined lesions in brain regions ipsilateral and contralateral to the nose side that was tested. No significant left:right differences in either olfactory sensitivity or identification were present, although in both cases mean performance was lower in the MS than in the control subjects (ps<0.0001). Scores on the two sides of the nose were positively correlated with one another (threshold r=0.56, p<0.0001; Identification r=0.71, p<0.0001). The percent of MS patients whose bilateral test scores fell below the 10th percentile of controls did not differ between the odor identification and detection threshold tests. Both left and right odor identification and detection test scores were weakly correlated with lesion volumes in temporal and frontal lobe brain regions (r's<0.40). Our findings demonstrate that MS does not differentially influence odor perception on left and right sides of the nose, regardless of whether sensitivity or identification is being measured. They also indicate that tests of odor identification and detection are similarly influenced by MS and that such influences are associated with central brain lesions.
authors: Department of Psychiatry and Department of Psychology & Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada.
authors: Kimberley P
authors: KP
authors: Good
authors: Smell and Taste Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Otorhinolarynology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
authors: Isabelle A
authors: IA
authors: Tourbier
authors: Smell and Taste Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Otorhinolarynology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
authors: Paul
authors: P
authors: Moberg
authors: Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
authors: Jennifer L
authors: JL
authors: Cuzzocreo
authors: Department of Radiology, Johns Hopkins Hospital, Baltimore, MD, United States.
authors: Rena J
authors: RJ
authors: Geckle
authors: Department of Radiology, Johns Hopkins Hospital, Baltimore, MD, United States.
authors: David M
authors: DM
authors: Yousem
authors: Center for Neuroscience and Regenerative Medicine, Henry Jackson Foundation, Bethesda, MD, United States.
authors: Dzung L
authors: DL
authors: Pham
authors: Smell and Taste Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Otorhinolarynology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States. Electronic address: richard.doty@uphs.upenn.edu.
authors: Richard L
authors: RL
authors: Doty
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology*; D009483:Neuropsychological Tests; D009812:Odorants; D000857:Olfaction Disorders / Q000209:etiology*; D012684:Sensory Thresholds / Q000502:physiology*
keywords: Brain laterality; Magnetic resonance imaging; Multiple sclerosis; Olfaction; Sex differences; Threshold; UPSIT