NORAM--an instrument used in the assessment of hypernasality: a clinical investigation.

The speech of 102 patients with complete unilateral and bilateral cleft lip and palate and 40 noncleft subjects was analysed using the NORAM (Nasal Oral Ratio Meter) instrument. The results obtained were compared with the perceptual judgments made by experienced listeners. A significant correlation was found between the NORAM values and the listener judgments. The NORAM instrument can thus be used as a complement to listener judgments in assessing hypernasality. A discussion of the acoustic and phonetic aspects of the differences between the instrumental and perceptual results is presented.