Table 9.

The thresholds corresponding to the first four Principal Components

Principal Component (PC)	Frequency (in Hz)
	250	500	1000	2000	4000	8000
PC1: Flat hearing loss	42	41	40	39	42	44
	45	45	42	42	45
PC2: High tone sensorineural loss	37	38	48	69	82	79
	46	46	55	76	89
PC3: Air-bone gap (flat)	78	77	75	71	75	76
	31	35	42	45	47
PC4: Air-bone gap (predominant at low tone)	50	59	76	76	50	32
	29	55	82	85	52