Figures and data in Poor coherence in older people's speech is explained by impaired semantic and executive processes

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7 figures, 3 tables and 2 additional files

Figures

Figure 1

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Process for computing coherence in speech samples.
https://doi.org/10.7554/eLife.38907.003

Figure 2

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Effects of age and task on speech rate and coherence *p<0.05; ***p<0.001.
https://doi.org/10.7554/eLife.38907.005

Figure 3

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Effects of semantic and executive abilities on coherence *p<0.05; **p<0.01; ***p<0.001.
https://doi.org/10.7554/eLife.38907.006

Figure 4

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(A) Principal components analysis identifying four latent speech factors. (B) Effects of semantic and executive abilities on factor scores. *p<0.05; **p<0.01; ***p<0.001.

https://doi.org/10.7554/eLife.38907.007

Figure 5

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Example trials from semantic tasks.

The correct response is highlighted in each case.

https://doi.org/10.7554/eLife.38907.008

Appendix 5—figure 1

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Results of tests of semantic processing.

Cong = congruent; Incon = incongruent; Lex Dec = lexical decision.

https://doi.org/10.7554/eLife.38907.018

Appendix 5—figure 2

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Reaction times on the manual secondary task.
https://doi.org/10.7554/eLife.38907.019

Tables

Table 1

Results of mixed effects models predicting global and local coherence.

https://doi.org/10.7554/eLife.38907.004

	Model 1			Model 2			Model 3
	B	Se	P	B	Se	P	B	Se	P
Global Coherence
(Intercept)	44.6	1.45	<0.001	44.6	1.43	<0.001	44.6	1.42	<0.001
Age	−2.30	0.54	<0.001	−1.97	0.50	<0.001	−0.68	0.73	.35
Task	−0.31	0.24	.20	−0.31	0.24	.20	−0.30	0.24	.21
Age*Task	−0.53	0.25	.056	−0.53	0.25	.052	−0.53	0.25	.052
Response length	−0.97	0.38	.014	−0.90	0.36	.016	−0.86	0.35	.019
Trails ratio				−1.61	0.45	<0.001	−1.71	0.42	<0.001
Semantic knowledge							−1.63	0.73	.028
Semantic selection							1.16	0.42	.007
Weak association							0.29	0.52	.58
Local Coherence
(Intercept)	26.8	1.36	<0.001	26.8	1.35	<0.001	26.8	1.34	<0.001
Age	−2.51	0.58	<0.001	−2.27	0.57	<0.001	−1.42	0.80	.081
Task	−0.16	0.34	.63	−0.16	0.33	.63	−0.16	0.34	.64
Age*Task	−0.55	0.32	.10	−0.55	0.32	.10	−0.55	0.32	.10
Response length	0.01	0.39	.98	0.09	0.38	.82	0.12	0.38	.74
Trails ratio				−1.16	0.45	.012	−1.23	0.43	.006
Semantic knowledge							−1.14	0.76	.14
Semantic selection							0.94	0.43	.034
Weak association							0.33	0.54	.54

Appendix 1—table 1

Demographic information and mean test scores for young and older participants.

https://doi.org/10.7554/eLife.38907.012

	Young adults	Older adults
N	30	30
Age	19.3 (2.2)	76.0 (8.3)
Sex M:F	8:22	15:15
Years of education	13.8 (0.9)	14.3 (3.0)
MMSE /30	28.8 (1.0)	29.2 (1.1)
Category fluency (items per category)	25.4 (5.4)**	21.1 (5.2)
Letter fluency (items per category)	12.9 (5.0)	16.4 (7.1)*
Trails A errors	0.1 (0.3)	0.1 (0.3)
Trails B errors	0.5 (1.0)	0.9 (1.4)
Trails A time (s)	26.9 (9.1)**	35.9 (11.7)
Trails B time (s)	46.2 (12.8)***	76.3 (34.9)
Trails ratio score (B time / A time)	1.84 (0.69)	2.12 (0.70)

Standard deviations are shown in parentheses. Asterisks indicate the significance of t-tests comparing young and older adults. *p<0.05; **p<0.01; ***p<0.001.

Appendix 3—table 1

Examples of high and low coherence responses.

https://doi.org/10.7554/eLife.38907.015

Example	Prompt	Response
Low GC (22), low LC (11). Older participant.	Which is your favourite season and why?	My favourite season is spring because it increases the amount of light that you receive from the sun. It’s not easy to know why the sun should get bigger but the more you think about it, the more you realise that it’s all because in earlier times, people worked out that the earth was a small ball and was affected by the sun, during its travels. In fact, if you’re listening to the test match you won’t hear anything from Australia unless you get up in the middle of the night and go through to the morning. And that seems to me to, for small boys anyway, is one of the main reasons why it’s quite effective to do that.
Low GC (26), high LC (37). Young participant.	Describe a typical visit to a restaurant.	I’d get changed. Once I’d got changed, I would get the bus or I would drive in with the family to a restaurant. We’d use the car. We’d drive through into town to get to the restaurant. We’d find a parking space and we’d have a longer walk into town. Once we get into town we’d go through, we’d go up past the bridges looking for a nice place, a place with a view. We’d walk through St. Andrews Square and look for somewhere with a balcony. We’d travel through maybe George Street to somewhere fancy to dine.
Moderate GC (44), low LC (16). Young participant.	What do people generally do when getting ready for work in the morning?	They usually, you know, get out of bed and stuff and then make their breakfast, and then make their lunch if they're going to be in for lunch as well. And get ready, put their clothes on, and then lock everything up again and leave, however they usually get there. So they might be on the bus or something. Like some people like to have a shower in the morning before work as well. I like to take the recycling out on the way to work, which is good. So they do lots of different things depending on what their work is and depending whether it's in the morning or they’re leaving at night time for work.
High GC (59), high LC (58). Older participant	Which is your favourite season and why?	My favourite season is spring which, where I live, is quite a dramatic season because there is a tremendous difference from winter, which is cold and everything is, all the flowers and plants appear to be dead, trees have no leaves. So once spring comes, the buds start coming on the trees, plants start bursting through the ground. The earliest ones are probably the snowdrops, followed by crocuses and daffodils and other spring bulbs. And then it moves on, as the spring develops, into the beautiful blossom of cherry and plum and I have a beautiful wild plum tree in my neighbour’s back garden, which I enjoy very much every spring. It’s my perfect spring tree. The weather generally begins to warm up a bit; we lose any likelihood of getting snow or ice, although it may still be wet and cold.