Introduction and aims of the work: Cochlear hearing loss is associated with damage to hair cells in the cochlea. Cochlear dead zones are regions where the inner hair cells and/or adjacent neurons are not functional. The presence of a DR can have several consequences for the perception of loudness, pitch and speech, even with the provision of proper amplification. The two most commonly used methods to detect DR are: measurement of PTCs and measurement of masked thresholds of a sinusoid in threshold-equalizing noise. Fast PTC test is a fast computer based method that aims to assess the frequency selectivity of the cochlea and detect dead regions. In this work we applied TEN test and f-PTC on subjects with cochlear hearing loss to diagnose dead regions. Subjects and methods: Experiment 1: The sharpness of the PTCs (Q10) and the typical shift of tips of the PTCs for 16 normal hearing subjects, when the tip frequency is estimated for the average of a forward and reverse sweep were obtained. The results were used to determine the mean, standard deviation and 95% confidence interval of the shifts in normal hearing subjects. Experiment 2: Thirty two adult hearing impaired patients were evaluated for the presence of dead regions by TEN and f-PTC test and HA satisfaction was assessed using IOI-HA questionnaire. Experiment 3: 10 adults with the same inclusion criteria as the previous experiment were assessed by f-PTC and Q10 values were compared to normative data. Conclusions and recommendations: f-PTC test is an easy fast method to diagnose DRs, estimate edge frequency and frequency resolution. DRs were found to be more common with a hearing loss of high frequency configuration. There was a good correlation between the results of the TEN test and f-PTC. Q10 values (as a measure of frequency resolution) showed abnormality despite the absence of DR. Presence or absence of dead regions was not related to age or gender or slope of audiogram. There was a good correlation between the results of the TEN test and f-PTC test. Applying the TEN test and the f-PTC before HA fitting would save the hassles of a refitting.