Normative Data for the Maryland CNC Test

Background: The Maryland consonant-vowel nucleus-consonant (CNC) Test is routinely used in Veterans Administration medical centers, yet there is a paucity of published normative data for this test. Purpose: The purpose of this study was to provide information on the means and distribution of word-recognition scores on the Maryland CNC Test as a function of degree of hearing loss for a veteran population. Research Design: A retrospective, descriptive design was conducted. Study Sample: The sample consisted of records from veterans who had Compensation and Pension (C&P) examinations at a Veterans Administration medical center (N = 1,760 ears). Data Collection and Analysis: Audiometric records of veterans who had C&P examinations during a 10 yr period were reviewed, and the pure-tone averages (PTA4) at four frequencies (1000, 2000, 3000, and 4000 Hz) were documented. The maximum word-recognition score (PBmax) was determined from the performance-intensity functions obtained using the Maryland CNC Test. Correlations were made between PBmax and PTA4. Results: A wide range of word-recognition scores were obtained at all levels of PTA4 for this population. In addition, a strong negative correlation between the PBmax and the PTA4 was observed, indicating that as PTA4 increased, PBmax decreased. Word-recognition scores decreased significantly as hearing loss increased beyond a mild hearing loss. Although threshold was influenced by age, no statistically significant relationship was found between word-recognition score and the age of the participants. Conclusions: Results from this study provide normative data in table and figure format to assist audiologists in interpreting patient results on the Maryland CNC test for a veteran population. These results provide a quantitative method for audiologists to use to interpret word-recognition scores based on pure-tone hearing loss.