Hearing aid experience and background noise affect the robust relationship between working memory and speech recognition in noise

Figures & data

Table1. Means (and SDs) of background variables, Hagerman and working memory tests.

	Noise	2–5 years (n = 66)	5–10 years (n = 40)	10 years or above (n = 42)	All participants (n = 148)
Age* (year)		59.68 (7.12)	62.3 (7.69)	63.43 (8.27)	61.45 (7.74)
PTA* (dB HL)		34.77 (9.49)	39.44 (7.69)	47.62 (10.24)	39.68 (10.66)
Daily hearing aid usage (h)		9.39 (5.76)	9.03 (5.64)	11.66 (5.19)	9.97 (5.63)
Years of education		13.26 (3.34)	13.18 (3.40)	13.65 (4.02)	13.28 (3.48)
Hagerman*** (dB SNR)	SSN	−5.60 (1.98)	−5.54 (1.49)	−4.28 (1.96)	−5.21 (1.93)
	4T	−0.95 (1.84)	−0.67 (1.36)	0.55 (1.65)	−0.45 (1.78)
Rhyme judgment (% correct)		87.07 (11.04)	86.73 (11.85)	87.19 (12.54)	87.01 (11.62)
Lexical access (reaction time, ms)		970.66 (183.38)	993.18 (238.49)	961.74 (168.80)	974.09 (194.76)
Physical matching (reaction time, ms)		979.26 (198.01)	998.15 (209.00)	966.51 (207.49)	980.64 (202.64)
Reading span (# of correct recall, max 28)		16.11 (3.34)	15.93 (3.78)	16.52 (4.17)	16.18 (3.69)
Semantic word-pair (# of correct recall, max 42)		18.06 (5.41)	17.20 (4.65)	16.93 (5.07)	17.51 (5.11)
VSWM (# of correct recall, max 42)		30.15 (5.80)	28.63 (6.92)	29.19 (5.88)	29.47 (6.13)
Weighted score of WMC (z-score)		0.19 (1.74)	−0.15 (1.68)	−0.00 (1.55)	−0.04 (1.67)

Asterisks indicate variables that were significantly different between subgroups.

*p < 0.05.

***p < 0.001.

Table 2. Correlations between speech recognition thresholds obtained in SSN and 4 T and individual working memory tests together with the weighted score of WMC.

Hearing aid experience	Noise	Reading span	Semantic word-pair	VSWM	Weighted score	Correlation comparison
All participants	SSN	−0.23**	−0.15	−0.21*	−0.26**	z = 2.39*
(n = 148)	4T	−0.28**	−0.26**	−0.29**	−0.37**
2–5 years	SSN	−0.37**	−0.33**	−0.37**	−0.44**	z = 0.57
(n = 66)	4T	−0.36**	−0.40**	−0.37**	−0.47**
5–10 years	SSN	−0.33*	0.09	−0.06	−0.14	z = 1.77
(n = 40)	4T	−0.43**	−0.11	−0.26	−0.37*
10 years or above	SSN	−0.08	0.06	−0.10	−0.06	z = 1.73
(n = 42)	4T	−0.21	−0.07	−0.22	−0.25
With age partialled out
All participants	SSN	−0.14	−0.10	−0.13*	−0.17*
	4T	−0.20*	−0.22**	−0.13**	−0.29**
2–5 years	SSN	−0.31*	−0.26*	−0.32**	−0.38**
	4T	−0.29*	−0.34**	−0.33**	−0.41**
5–10 years	SSN	−0.17	0.21	0.17	0.10
	4T	−0.31	−0.03	−0.09	−0.20
10 years or above	SSN	−0.04	−0.02	0.02	−0.08
	4T	−0.23	−0.15	−0.12	−0.19
With age and PTA partialled out
All participants	SSN	−0.20*	−0.07	−0.12	−0.18*
	4T	−0.27**	−0.21**	−0.22**	−0.32**
2–5 years	SSN	−0.32*	−0.22	−0.28*	−0.35**
	4T	−0.30*	−0.31*	−0.29*	−0.38**
5–10 years	SSN	−0.17	0.21	0.18	0.11
	4T	−0.30	−0.03	−0.08	−0.20
10 years or above	SSN	−0.08	0.01	−0.07	−0.07
	4T	−0.25	−0.14	−0.20	−0.29

The strength of correlations obtained in SSN and 4 T were compared for all participants and within each subgroup using the Fisher r-to-z transformation. Correlations with age alone and age together with PTA partialled out are also shown. These partial correlations show a similar pattern to the non-partialled ones and hence not used in the subsequent analyses.

*p < 0.05.

**p < 0.01.

Table 3. Results of the regression analyses (backward elimination).

Hearing aid experience	Noise	Regression model	Significant predictors	Eliminated predictors	Sig	R^2	Adj R^2	R^2 change	B	Std err b	beta	Partial corr
2–5 years	SSN	Full model			***	0.45	0.41
			–	Semantic word-pair				0.00
			–	Age				−0.02
			–	VSWM				−0.02
		Best model			***	0.41	0.39
			PTA	–	***				0.66	0.12	0.53	0.56
			Reading span	–	**				−1.06	0.35	−0.30	−0.30
	4T	Full model			***	0.45	0.40
			–	Reading span				−0.01
			–	VSWM				−0.02
			–	Age				−0.00
		Best model			***	0.42	0.39
			PTA	–	***				0.09	0.02	0.44	0.42
			Semantic word-pair	–	*				−0.48	0.19	−0.26	−0.25
5–10 years	SSN	Full model			**	0.43	0.35
			–	PTA				−0.01
			–	VSWM				−0.03
			–	Reading span				−0.04
			–	Semantic word-pair				−0.03
		Best model			***	0.32	0.30
			Age	–	***				0.11	0.03	0.56	0.56
	4T	Full model			**	0.40	0.32
			–	VSWM				0.00
			–	PTA				−0.00
			–	Semantic word-pair				−0.00
		Best model			***	0.40	0.37
			Age	–	**				0.09	0.02	0.49	0.51
			Reading span	–	*				−0.36	0.19	−0.26	−0.31
10 years or above	SSN	Full model				0.15	0.03
			–	Semantic word-pair				−0.00
			–	VSWM				−0.00
			–	Reading span				−0.01
			–	PTA				−0.06
			–	Age				−0.08
	4T	Full mode			*	0.27	0.17
			–	Semantic word-pair				−0.00
			–	VSWM				−0.02
			–	Age				−0.04
		Best model			**	0.21	0.17
			PTA	–	**				0.07	0.02	0.42	0.41
			Reading span	–	*				−0.12	0.06	−0.29	−0.30

All full models and the best models which are significant model are shown.

*p ≤ 0.05.

**p < 0.01.

***p < 0.001.