3.1.3. Statistical Analyses

The Z-score was calculated following the fluency calibration of Cardebat [23]. This calibration takes into account the type of fluency as well as the gender, age and education level of the participants. Cochlear implant auditory gain was calculated as the difference between post-implant Pure Tone Audiometry (PTA) and pre-implant PTA. The Shapiro-Wilk test was used to check the normal distribution of the data. Since the data followed the normal distribution, a paired-sample t-test was used to compare the Z-score of preand post-implantation fluencies. In order to compare the differences in Z-scores of postimplantation and pre-cochlear implantation phonemic fluencies and post-implantation and pre-cochlear implantation semantic fluencies between acquired and congenital deafness, we used an independent samples t-test and a Mann Whitney test according to the distribution of the data. Pearson correlations were performed to analyse the relationship between differences in fluency scores and implant gain. Significant results are reported as *p* < 0.05 (*p* < 0.05 \*, *p* < 0.01 \*\*, *p* < 0.001 \*\*\*).

#### *3.2. Results*

Of the 43 subjects, one subject was below the pathological threshold (Z = −2) in phonemic fluency post cochlear implantation. For semantic fluency, 2 subjects were below the pathological threshold pre- and post-cochlear implantation. One participant went from a non-pathological to a pathological Z-score after implantation. One participant went from a pathological to a non-pathological Z-score after implantation.

Table 4 shows the results of the pre- and post-cochlear implantation Z-scores in the two fluency conditions (phonemic and semantic).


**Table 4.** Phonemic and semantic fluency Z-score results pre and post cochlear implantation.

The results show a higher Z-score for post-implantation phonemic fluency than for pre-implantation phonemic fluency. The *p*-value shows that the result is significant (*p* = 0.024 \*). In semantic fluency, the post-implantation Z-score is slightly higher than the pre-implantation Z-score, but this value is not significant (*p* = 0.863).

Table 5 describes the results of the differences in the post and pre cochlear implantation Z-scores according to the origin of the deafness (acquired deafness or congenital deafness).

**Table 5.** Results of Z-score differences in post- and pre-cochlear implant phonemic fluency and postand pre-cochlear implant semantic fluency between acquired and congenital deafness.


The differences in phonemic fluency Z-scores post implant and pre implant show a gain for both groups. The mean is higher in the group of subjects with acquired hearing loss than in the group with congenital hearing loss.

The difference in semantic fluency Z-scores post implant and pre implant shows a small gain for the group of subjects with an acquired hearing loss. For subjects with congenital hearing loss the difference in semantic fluency Z-scores post implantation and pre cochlear implantation shows a small loss. No significant difference was found between the two groups in the post-implantation condition in either fluency (*p* = 0.751 and *p* = 0.692).

Figure 2 shows the distribution of the differences in Z-scores (in phonemic and semantic fluency) post and pre-implant and implant gain.

**Figure 2.** Distribution of post- and pre-implantation Z-score differences and implant gain.

Figure 3 shows the distribution of pre-implantation phonemic and semantic Z-score differences and implant gain.

**Figure 3.** Distribution of pre-implant phonemic and semantic Z-score differences and implant gain.

The results show no correlation between pre-implantation phonemic and semantic Z-score differences and implant gain (*r* = 0.119, *p* > 0.05).
