title: [Oral diadochokinesis among Japanese aged over 55 years: analysis of standard values].
abstract: OBJECTIVE
  We investigated oral diadochokinesis (OD) among 212 Japanese aged over 55 years to assess the standard values of articulation ability.
  
  
  METHODS
  Each subject repeatedly produced the OD syllables /pa/, /ta/, and /ka/. Subjects were divided into three age-groups (55-64 years, 65-74 years, and over 75 years) and by gender to compare the number of OD syllables per second. We also calculated the lower limit of values that determined the standard range for OD syllables.
  
  
  RESULTS
  The number of all OD syllables in the over-75 age-group was significantly lower than in the 55-64 group. The number of OD /pa/ syllables in the over-75 group was significantly lower than in the 65-74 group. The number of OD /ta/ syllables in the 65-74 group was significantly lower than in the 55-64 group. The lower limit of the standard values for OD /pa/, /ta/, and /ka/ was, respectively, as follows: 4.9, 4.7, and 4.5 times in the 55-64 group; 3.8, 4.1, and 3.7 times in the 65-74 group; and 3.8, 3.3, and 2.6 times in the over-75 group. Among women, the number of OD /pa /, /ta/, and /ka/ syllables was significantly lower in the over-75 group than in other age-groups.
  
  
  CONCLUSIONS
  We demonstrated that the lower limit of standard OD values is a means of assessing articulation in elderly subjects. We found that OD /ta/ tends to decrease from age 65 years. The decline in articulation ability clearly begins earlier in women than in men.
authors: School of Health Science, Kyushu University of Health and Welfare.
authors: Shuichi
authors: S
authors: Hara
authors: Hiroko
authors: H
authors: Miura
authors: Kiyoko
authors: K
authors: Yamasaki
mesh_terms: D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013060:Speech / Q000502:physiology*