Table 1 Demographic, clinical and general neuropsychological data for the participant groups

  No. of participants, M/F

8/9

3/6

7/3

6/1

4/6

  Age, years

67.7 (5.2)

69.6 (9.2)

64.9 (7.6)

66.3 (6.1)

70.5 (8.9)

  Handedness (R/L/A)

16/0/1

8/1/0

10/0/0

7/0/0

9/1/0

  Education, years

16.2 (2.6)

14.9 (3.3)

14.8 (3.3)

15.1 (2.3)

14.0 (1.8)

  MMSE (total possible score of 30)

29.7 (0.5)

24.4 (5.1)

25.2 (5.3)

18.4 (8.0)

19.1 (5.1)

  Symptom duration, years

NA

3.6 (1.3)

5.3 (2.0)

3.3 (1.3)

6.1 (3.1)

  PTA best ear (N/mild/moderate)

4/11/0^a

1/6/1^b

4/6/0

3/2/1^b

2/5/0^c

  WASI Verbal IQ

127.6 (5.9)

76.4 (17.7)

67.5 (22.4)

60.6 (8.3)

91.8 (19.3)

  WASI Performance IQ

121.7 (13.7)

100.3 (21.8)

110.1 (21.8)

79.4 (13.1)

84.7 (20.3) ^b

  RMT Words (total possible score of 50)

48.4 (1.9)

40.3 (7.3) ^a

33.4 (5.7) ^d

31.0 (7.3) ^a

15.7 (3.5) ^b,e

  RMT Faces (total possible score of 50)

44.5 (4.4)

39.1 (4.0)^a

35.0 (6.2) ^c

31.7 (5.2)

18.2 (3.2) ^b,e

  Digit span forward (maximum)

7.2 (1.0)

4.6 (1.4)

7.2 (1.2)

4.0 (1.3) ^b

6.2 (0.9)

  Spatial span forward (maximum)

5.5 (0.8)^a

4.8 (1.2)

5.5 (0.9)

3.3 (0.8)

NA

  Digit span reverse (maximum)

5.1 (1.1)

3.0 (0.9) ^b

5.4 (2.1)

2.6 (0.9) ^a

3.8 (0.8) ^b

  Spatial span reverse (maximum)

5.4 (0.9)^a

3.8 (1.5)

5.2 (1.2)

3.0 (1.0)

NA

  Letter fluency (total)

18.4 (5.1)

6.2 (6.0)

10.2 (4.5) ^b

4.5 (6.5) ^c

9.9 (6.0)

  Category fluency (total)

25.6 (5.4)

9.7 (4.9)

17.6 (37.2) ^b

5.0 (7.5)

6.3 (4.9)

  Trails Making Test A (seconds)

31.8 (8.0)

71.3 (36.9)

45.1 (37.2)

79.2 (37.6) ^a

92.8 (40.6) ^a

  GDA Calculation (total possible score of 24)

13.6 (4.1)

6.0 (6.4) ^b

15.0 (7.3)^a

3.0 (2.2) ^c

3.4 (4.4) ^c

  VOSP Object Decision (total possible score of 20)

18.9 (1.0)

17.4 (1.9)

16.2 (3.1)

15.3 (2.6)

15.5 (2.3)

   PALPA-3 (total possible score of 36)

35.1 (1.1)^a

34.6 (2.3)

35.3 (1.0)

31.1 (5.2)

NA

   GNT (total possible score of 30)

27.1 (2.5)

13.8 (4.8) ^a

1.2 (2.2) ^d

9.3 (10.3)

12.7 (9.2) ^b

   BNT (total possible score of 30)

29.4 (0.6)^a

22.0 (5.0)

6.4 (5.2) ^a

9.9 (8.5)

NA

   BPVS (total possible score of 51)

48.3 (5.6)

33.3 (14.9)

9.5 (14.8)

29.3 (7.3)

40.1 (5.5) ^b

   Synonyms concrete (total possible score of 25)

24.5 (0.6)^a

19.0 (4.2) ^b

16.6 (3.3) ^c

17.7 (2.8)

NA

   Synonyms abstract (total possible score of 25)

24.5 (0.8)^a

19.3 (4.5) ^b

15.6 (3.6) ^c

17.8 (4.0) ^b

NA

   PALPA-55 (total possible score of 24)

23.9 (0.4)^a

19.1 (4.5)

22.3 (2.1)^c

15.7 (4.9)

NA

   Polysyllabic words (total possible score of 45)

44.8 (0.9)^a

35.1 (3.6) ^b

48.9 (0.6)

34.5 (2.6)

NA

   Short sentences (total possible score of 10)

9.7 (0.6)^a

4.0 (2.9) ^a

7.8 (1.7) ^a

4.6 (2.2)

NA

   BST (total possible score of 30)

26.6 (1.6)^a

14.2 (8.0)

13.0 (7.5) ^b

13.0 (7.3) ^b

NA