title: Decline of gustatory sensitivity with the progression of Alzheimer's disease.
abstract: BACKGROUND
  Patients with Alzheimer's disease (AD) manifest various impairments in eating behavior. However, few previous studies have directly investigated the gustatory function of AD patients, and results have been inconsistent.
  
  
  METHODS
  Thirty-two AD patients (Clinical Dementia Rating (CDR) 0.5/1/2, respectively 11/15/6 patients) and 22 normal control participants were examined to measure detection and recognition thresholds of the four elemental tastes (sweet, salty, sour, and bitter), and their ability to discriminate between tastes. Effects of demographic and clinical factors (age, sex, histories of alcohol and tobacco consumption, and CDR grade) on gustatory threshold were examined using ordinal logistic regression analysis. Performance was compared between AD and control groups.
  
  
  RESULTS
  Total threshold values (the sum of threshold grades for the four tastes) for detection and recognition of tastes were significantly higher in the AD group. Detection thresholds for sweet, salty, and bitter, and recognition thresholds for sweet and sour, were also significantly higher in the AD group. Ordinal logistic regression analysis revealed that CDR grade was the only factor that significantly affected both total threshold values. Regarding taste discrimination, there were no significant differences between the AD group and control group.
  
  
  CONCLUSIONS
  These findings suggest that progression of dementia severity accompanies gustatory decline. Although it seemingly paradoxical, weight loss and preference for sweet tastes are frequently, often simultaneously, observed in AD. Gustatory dysfunction may be partially involved in these symptoms. Thus, the nutritional care of patients with AD could be improved by making the taste of meals stronger, while controlling calorie and mineral intake.
authors.affiliation: Department of Clinical Rehabilitation,Osaka Prefecture University Graduate School of Comprehensive Rehabilitation,Habikino-City,Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Sakai
authors.affiliation: Department of Neuropsychiaty,Faculty of Life Sciences,Kumamoto University,Kumamoto-City,Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Ikeda
authors.affiliation: Department of Phychiatry,Osaka University Graduate School of Medicine,Suita-City,Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kazui
authors.affiliation: Department of Psychiatry,Asakayama Hospital,Sakai-City,Japan.
authors.forename: Kazue
authors.initials: K
authors.lastname: Shigenobu
authors.affiliation: Department of Clinical Rehabilitation,Osaka Prefecture University Graduate School of Comprehensive Rehabilitation,Habikino-City,Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishikawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology*; D016022:Case-Control Studies; D018450:Disease Progression; D004408:Dysgeusia / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D013649:Taste / Q000502:physiology*; D013652:Taste Threshold
keywords: Alzheimer’s disease; clinical rating scale; gustatory threshold