Hearing impairment, cognition and speech understanding: exploratory factor analyses of a comprehensive test battery for a group of hearing aid users, the n200 study

Figures & data

Table 1. Summary test descriptions and measurement objectives for all tests variables.

Name (abbreviation)	Description	Measurement objective
Hearing tests
Pure-tone audiometry	Obtained air- and bone-conduction thresholds at 0.125 through 8 kHz	To measure hearing acuity
Threshold-equalizing noise – hearing level (TEN HL)	Obtained masked thresholds at 0.5, 1, 2 and 4 kHz	To identify dead regions of inner hair cells
Distortion product oto-acoustic emissions (DPOAE)	Assessed oto-acoustic emissions at 1, 2 and 4 kHz and at 40, 50 and 60 dB SPL	To measure integrity of outer hair cells
Temporal fine structure low frequency test (TSF-LF)	Judged which one of the two tones contained an interaural phase shift	To measure interaural phase difference thresholds for pure tones/general ability to use pitch information
Spectro-temporal modulation (STM) test	Judged which one of the two sound intervals contained spectro-temporal modulations	To measure modulation detection
Phonetically balanced (PB) word lists	Repeated verbally consonant-vowel-consonant monosyllabic words heard in quiet	To measure speech perception
Cognitive tests
Phonological tests
Consonant gating	Identified the consonants in vowel–consonant–vowel syllables	To assess individual skill in early identification of phonetic information
Vowel gating	Identified the vowels in consonant–vowel syllables	To assess individual skill in early identification of phonetic information
Vowel duration discrimination	Judged which one of the two sound tokens in each pair was longer	To assess individual ability to discriminate duration
Rhyme judgment	Judged whether or not two visually presented words rhymed	To assess phonological processing abilities
Semantic long-term memory access speed
Physical matching (PM) test	Judged whether or not two visually presented letters were identical	To measure long-term memory access speed
Lexical decision making (LD) test	Judged whether a string of three letters constituted a real word or not	To measure lexical access speed
Working memory
Non-word serial recall (NSR)	Repeated verbally lists of non-words shown on a screen	To measure phonological processing based on working memory for phonological information devoid of semantic information
Reading span test (RST)	Judged whether or not each visually presented sentence was sensible, and after a sequence of sentences, recalled either the first or the last word of all sentences in the sequence	To measure working memory, a test taxing memory storage and processing simultaneously
Semantic Word-Pair Test (SWPST)	Judged which one of the two visually presented words (word-pairs) was a living object, and after a sequence of word-pairs, recalled either the first or the second words of all word-pairs	To measure working memory that does not include syntactic elements in the processing and storage components
Visuo-spatial working memory test (VSWM)	Judged whether the two ellipsoid shapes visually presented in one of the squares in a 5 × 5 grid were identical, and after a sequence, recalled where in the grid the ellipsoid-pairs were presented	To measure non-verbal working memory
Executive and inference-making functions
Shifting test	Specified whether a number-letter pair contained an odd or even number in half of the trials and contained a capital or small letter in the other half of the trials	To measure shifting ability
Updating test	Recalled the last word presented in 4 out of 6 pre-defined categories	To measure updating ability
Inhibition test	Responded to any digit presented on a screen except when digit 3 appeared	To measure the ability to deliberate responses
Text reception threshold (TRT)	Repeated orally visually presented sentences, masked by bars	To measure reception threshold of masked text
Sentence completion test (SCT)	Filled in the missing words in each incomplete sentence	To assess context-bound verbal inference-making ability
Logical Inference-making test (LIT)	Answered to a question with help of two statements presented on screen simultaneously	To measure text-based inference-making ability
General cognitive functioning
Mini mental state examination (MMSE)	Eleven questions probing different mental or cognitive functions such as orientation to time and place, immediate recall, and attention	A screening test for dementia
Rapid automatized naming (RAN)	Named the shapes, colours, or shapes and colours of visual stimuli	A quick test of cognitive speed and dementia
Raven	Chose one out of the 6 alternatives to complete an overall visual pattern	To measure non-verbal reasoning ability (fluid intelligence)
Outcome tests
Swedish Hearing In Noise Test (HINT)	Repeated verbally sentences heard in noise	To measure speech recognition in noise threshold (50%) in noise
Hagerman sentences	Repeated verbally sentences heard in different conditions of noise and noise reduction settings	To measure speech recognition in noise threshold (50% and 80%) in noise
Samuelsson & Rönnberg	Repeated verbally sentences heard in noise in auditory only and audiovisual modalities, with or without contextual cues	To measure contextually cued speech recognition in noise
Auditory interference making (AIM)	Answered to a text-based question with help of a statement presented auditorily in noise	A text- and auditory-based test, measuring inference-making ability
Speech, Spatial and Qualities of hearing scale	Self-reported aided performance and abilities in speech perception, spatial hearing and qualities of hearing (50 questions in total)	Self-assessment of speech perception, spatial hearing and qualities of sound and hearing

Table 2. Summary of means and SDs for all the main dependent variables used in the factor analyses.

		M	SD	Range
Hearing variables
Air-conduction PTA4 (left) (dB HL)		39.09	10.88	11.25–75.00
Air-conduction PTA4 (right) (dB HL)		38.91	11.27	10.00–82.50
Bone-conduction PTA4 (left) (dB HL)		37.11	10.07	8.75–63.75
Bone-conduction PTA4 (right) (dB HL)		37.17	10.21	10.00–70.00
Threshold-Equalizing Noise and Hearing Level (TEN HL at 2 and 4 kHz in both ears, number of dead regions)		0.39	0.90	0–7
Distortion Product Oto-Acoustic Emissions (DPOAEs at 1, 2 and 4 kHz and at all levels in both ears,  number of emissions present)		2.12	1.14	0–5
Temporal Fine Structure sensitivity (TFS LF)		59.30	75.13	5.30–487.96
STM_threshold1_left (dB SNR)		−2.71	4.12	−14.33 to 0.97
STM_threshold2_left		−2.95	4.16	−13.00 to 0.93
STM_threshold3_left		−2.77	3.87	−13.33 to 0.90
STM_threshold1_right		−3.77	4.26	−14.67 to 0.97
STM_threshold2_right		−3.77	4.20	−15.00 to 0.96
STM_threshold3_right		−3.91	4.45	−16.00 to 0.97
Phonetically Balanced word test (PB, % correct)		94.75	5.92	68–100
Cognitive variables
Consonant gating (auditory) (average IP, in ms)		289	105	96–640
Vowel gating (auditory) (average IP, in ms)		223	86	112–376
Consonant gating (audiovisual) (average IP, in ms)		196	54	48–456
Vowel gating (audiovisual) (average IP, in ms)		208	81	64–432
Vowel duration discrimination (auditory, errors)		7.17	4.63	0.00–21.00
Vowel duration discrimination (audiovisual, errors)		7.09	4.93	0.00–26.00
Rhyme judgment (% correct)		87.27	11.20	47–100
Rhyme judgment (response time, in ms)		1685	404	985–3204
Physical matching (PM, response time, in ms)		976	207	552–1575
Lexical decision making (LD, response time, in ms)		969	187	652–1675
Non-word serial recall (NSR, max score = 42)		24.33	5.62	10–39
Reading span (RST, max score = 28)		16.07	3.83	5–26
Semantic word-pair span test (SWPST, max score = 42)		17.49	5.39	3–38
Visuo-spatial working memory (VSWM, max score = 42)		29.34	6.10	9–42
Shifting cost (in ms)		760	592	−837 to 2982
Updating task (max score = 16)		10.15	2.87	0–16
Inhibition task (error rates)		1.82	2.04	0–17
Text Reception Threshold (TRT, % unmasked text)		55.23	5.32	39.67–77.23
Sentence completion (SCT, % correct)		83.25	14.98	28.95–100.00
Logical Inference-making Test (LIT, % correct)		64.34	16.80	12–88
Mini Mental Test (max score = 30)		28.63	1.50	20–30
Rapid Automatised Naming (difference, in sec)		5.36	6.60	−13.40 to 32.85
Rapid Automatised Naming (RANCS, average response time, in sec)		60.35	10.95	37.80–110.63
Raven total score (max score = 24)		15.47	4.66	2–24
Outcome variables
Hearing-In-Noise Test (HINT, dB SNR)		−1.43	1.85	−4.82 to 12.00
Hagerman test (dB SNR)
Stationary noise
Linear amplification, no noise reduction	50%	−6.23	1.59	−10.78 to −1.89
	80%	−1.93	2.95	−8.00 to 9.56
Linear amplification, with noise reduction	50%	−11.22	1.66	−15.11 to −3.22
	80%	−5.67	3.12	−10.67 to 5.22
Fast-acting compression, no noise reduction	50%	−5.91	1.61	−10.00 to −1.67
	80%	−0.48	3.58	−7.11 to 13.44
Four-talker babble
Linear amplification, no noise reduction	50%	−0.94	1.69	−8.11 to 3.22
	80%	3.83	2.84	−1.78 to 12.89
Linear amplification, with noise reduction	50%	−7.93	1.57	−12.22 to −0.89
	80%	−2.33	3.10	−7.78 to 9.22
Fast-acting compression, no noise reduction	50%	−0.31	1.88	−6.78 to 6.11
	80%	4.88	2.87	−0.44 to 14.00
Samuelsson & Rönnberg (% correct)
Auditory, no contextual cues		22.99	16.83	0–83
Auditory, with contextual cues		26.25	17.63	0–96
Audiovisual, no contextual cues		59.04	19.28	0–96
Audiovisual, with contextual cues		61.85	18.83	0–93
Auditory Inference-Making (AIM, max = 16 correct)		70.97	17.96	25–100
Speech, Spatial and Qualities of hearing scale (SSQ, max = 500)		324.66	78.21	137.23–493.15

Figure 1. Hearing thresholds, means and SDs for the entire frequency range measured for the 200 hearing-impaired participants.

Figure 2. Insertion gain response curves for the linear amplifications (upper panel) and amplification with fast-acting compression (lower panel). Curves in solid lines represent insertion gain based on the average hearing thresholds at 125 through 8000 Hz. Curves in dotted lines represent insertion gain response based on hearing thresholds one standard deviation above/below average.

Figure 3. Overview of the exploratory factor analyses.

Table 3. Summary of all factor analyses.

		KMO	Explained variance (%)
HEARING factor analyses
LEVEL 1
	PTA	0.76	94.2
	STM	0.87	73.2
LEVEL 2
	Hearing global	0.57	32.1
COGNITION factor analyses
LEVEL 1
	Phonology	0.60	34.3
	Speed	0.62	70.6
	Working memory	0.74	53.0
	Executive functions	0.68	30.8
	General Cog. Function	0.50	43.7
LEVEL 2
	Cognition global	0.76	51.0
OUTCOME factor analyses
LEVEL 1
	Hagerman	0.91	57.1
	Samuelsson & Rönnberg	0.68	66.4
LEVEL 2
	Outcome global	0.52	43.8

Table 4. Summary of LEVEL 2 Factor analyses. The scale has been reversed for some variables (marked with *) such that higher values on all variables represent better HEARING, COGNITION, and speech in noise OUTCOME abilities. This was done to make the interpretations of the factors easier.

	Factor
HEARING factor analyses	SENSITIVITY	TEMPORAL FINE STRUC
LEVEL 1 Factor PTA*	0.91	0.05
TEN HL*	0.06	0.16
DPOAE*	−0.29	0.03
TFS-LF*	−0.29	0.92
LEVEL 1 Factor STM*	0.10	0.48
PB word test	0.37	0.34
COGNITION factor analyses	COGNITION
LEVEL 1 Factor Phonology*	0.59
LEVEL 1 Factor Speed*	0.53
LEVEL 1 Factor Working Memory	0.63
LEVEL 1 Factor Executive Functions*	0.92
LEVEL 1 Factor General Cog. Func.	0.43
OUTCOME factor analyses	CONTEXT	NO CONTEXT
HINT*	0.87	0.32
LEVEL 1 Factor Hagerman*	0.25	0.83
LEVEL 1 Factor Samuelsson   & Rönnberg	−0.52	0.08
Hannon & Daneman	−0.05	0.40
SSQ	−0.02	0.41

Table 5. Correlations among the LEVEL 2 components.

Variables	SENSITIVITY	TEMPORAL	CONTEXT	NO CONT.
COGNITION	0.17	0.37	0.20	0.44
SENSITIVITY		0.32	0.24	0.44
TEMPORAL			0.24	0.45
CONTEXT				0.36

All correlations are significant, the COGNITION-SENSITIVITY correlation is significant at p < 0.05 and the remaining correlations are significant at p < 0.001.

Table 6. Correlations among the LEVEL 2 components, with age partialled out.

Variables	SENSITIVITY	TEMPORAL	CONTEXT	NO CONT.
COGNITION	0.13	0.30	0.16	0.37
SENSITIVITY		0.29	0.22	0.42
TEMPORAL			0.20	0.38
CONTEXT				0.33

All but the COGNITION–SENSITIVITY correlation are significant; the 0.16 coefficient is significant at p < 0.05 level; the 0.20–0.22 coefficients are significant at p < 0.01, and the remaining coefficients are significant at p < 0.001.