title: Odour perception following bilateral damage to the olfactory bulbs: a possible case of blind smell.
abstract: BACKGROUND
  Unconsciously detected chemicals may affect human behaviour (Kirk-Smith et al., 1983; Stern and McClintock, 1998; Zucco et al., 2009), likeability judgements (Li et al., 2007) and brain activity (Lorig et al., 1990; Sobel et al., 1999). No studies, however, have investigated blind smell - the hypothetical olfactory counterpart of blindsight (Weiskrantz et al., 1974).
  
  
  METHODS
  In this report, free and cued olfactory identification of suprathreshold odorants varying in irritancy (i.e., low or no irritant odours versus irritant odours), and taste identification abilities, were examined in patient MB who had undergone surgery for a meningioma. Post-operative imaging revealed encephalomalacia in the left gyrus rectus, with ablation of the left olfactory bulb and damage to the right, subcortical abnormality on the left near the orbital cortex, and damage to a small section of the right gyrus rectus.
  
  
  RESULTS
  On free identification MB, while denying a capacity to smell the odours, still correctly identified some and detected others significantly above chance. In contrast, awareness always accompanied correct detections of irritant odours. Cued odour identification was at chance and no taste impairments were observed.
  
  
  CONCLUSIONS
  We suggest, tentatively, that MB's unusual pattern of awareness when detecting and identifying odours relative to irritant odours may represent an example of 'blind smell'.
authors.affiliation: Dipartimento di Psicologia Generale, Università di Padova, Italy. zucco@unipd.it
authors.forename: Gesualdo M
authors.initials: GM
authors.lastname: Zucco
authors.forename: Massimo
authors.initials: M
authors.lastname: Prior
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Sartori
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Stevenson
mesh_terms: D000328:Adult; D001364:Awareness / Q000502:physiology; D002540:Cerebral Cortex / Q000293:injuries / Q000473:pathology; D003399:Craniotomy / Q000009:adverse effects; D004678:Encephalomalacia / Q000000981:diagnostic imaging / Q000523:psychology; D006801:Humans; D007509:Irritants; D008279:Magnetic Resonance Imaging; D008297:Male; D008579:Meningioma / Q000601:surgery; D009483:Neuropsychological Tests; D019635:Neurosurgical Procedures / Q000009:adverse effects; D009812:Odorants; D009830:Olfactory Bulb / Q000293:injuries*; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000523:psychology; D011597:Psychomotor Performance / Q000502:physiology; D011859:Radiography; D021641:Recognition, Psychology / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D012903:Smell / Q000502:physiology*
chemical_list: D007509:Irritants