Background
Methods
Reappraisal of ERP abnormalities in ASD based on previously published studies
Study | Demographics: final N (age range: mean ± SD), males %) | EEG system/Reference | Stimuli | Task | N170 latency face superiority (effect size d/g*) | N170 amplitude face inversion (effect size d/g*) | P1 amplitude face inversion (effect size d/g*) | Other ERP findings |
---|---|---|---|---|---|---|---|---|
Tye et al., 2013 [31] | ASD: 19 (8–13:11.7 ± 1.7, 100%) ASD + ADHD: 26 (8–13:10.6 ± 1.7, 100%) ADHD: 18 (8–13:10.5 ± 1.9, 100%) TD: 26 (8–13:10.6 ± 1.8, 100%) | 62 Acticap/Average | Female faces upright/inverted with gaze direct/averted
No fixation cross
| Count flags among fixation | ASD/ASD + ADHD vs. TD + ADHD: d = 0.38, n.s. | n.s. | Enhanced N170 amplitude in Left Hemisphere | |
Churches et al., 2012 [30] | ASD: 10 (30 ± 6.2, 100%) TD: 13 (30 ± 4.8, 100%) |
32 Neuroscan/Nose
| Faces/face-like objects/non-face stimuli
No fixation cross
| Motor response on flower | n.s. | Smaller N170 amplitude for non-face like objects | ||
Webb et al., 2012 [29] | ASD: 32 (18–44:23.1 ± 6.9, 94%) TD: 32 (18–43:23.7 ± 6.7, 91%) | 128 EGI/Average | Faces/houses, upright/inverted, scrambles faces | Motor response on scrambled faces | 0.56/0.54 | n.s. | +, p < 0.05 | Face inversion effect on P1/N170 slope: d = 0.63/g* = 0.61 |
McPartland et al., 2011 [27] | ASD: 36 (11.2 ± 3.4, 89%) TD: 18 (12.6 ± 2.4, 83%) | 256 EGI/Average | Faces/houses, upright/inverted (inverted houses not analyzed) | Motor response on repeated stimuli | 0.63/0.61 | 0.41/0.40 | −0.10/−0.10, n.s. | |
Hileman et al., 2011 [28] |
ASD: 27 (9.4–17.4:13.2 ± 2.7, 85%)
TD: 22 (9.0–16.9:14.3 ± 2.0, 82%)
|
128 EGI/Average
|
Emotional faces, upright/inverted vehicle
No fixation cross
|
Count female faces/left pointing cars
|
−0.65/− 0.63, n.s.
|
−0.43/− 0.42, n.s.
|
1.09/1.05
|
Strange data: positive N170, no face inversion effect even in TD
|
Churches et al., 2010 [26] | ASD: 12 (31.4 ± 6.7, 100%) TD: 13 (29.3 ± 4.6, 100%) |
32 Neuroscan/Nose
| Faces/Chairs
No fixation cross
| Stimulus repetition detection task | n.s. | Modulation by attention | ||
O’Connor et al., 2007 [25] | ASD: 15 (18–41:23 ± 4, 100%) TD: 15 (19–37:18 ± 15,100%) | 128 EGI/Average | Sad/neutral faces/eyes/months/objects | Motor response on sad | 0.67/0.63 | |||
Webb et al., 2006 [24] | ASD: 27 (2.7–4.5:3.7 ± 0.3) TD: 18 (2.7–4.5:3.7 ± 0.6) DD: 18 (2.7–4.5:3.7 ± 0.4) % of males not reported | 64 EGI/Average | Familiar and unfamiliar faces and objects
No fixation cross
| No task | 0.56/0.54 | N170 precursor Larger ERPs to objects | ||
McPartland et al., 2004 [16] | ASD: 9 (15–42:21 ± 8, 89%) TD: 15 (16–37:24 ± 6, 93%) | 128 EGI/Average | Faces/furniture, upright/inverted, butterflies as targets (inverted furniture not analyzed)
No fixation cross
| Count butterflies | 1.19/1.10 | 0.18/0.17, n.s. | ||
Dawson et al., 2005 [45] | Parents of ASD: 21 (29–52:38.5, 48%) Parents of TD: 21 (28–51:38.9, 38%) | 128 EGI/Average | Faces, inverted/upright, chairs
No fixation cross
| Count scrambled faces | 0.62/0.59 | Smaller N170 amplitude in Right Hemisphere for faces |
New data collection
Subjects
Autism spectrum disorders, ASD | Unaffected siblings, US | Unaffected controls, UC | Unaffected fathers, UF | |
---|---|---|---|---|
n
| 49 | 36 | 53 | 18 |
Age, years | 15.2 ± 2.7 | 15.5 ± 2.5 | 15.5 ± 2.0 | 44.1 ± 7.1 |
SRS | 90 ± 31 | 23 ± 18 | 21 ± 17 | 29 ± 14 |
Caucasian | 92% | 89% | 76% | 94% |
Right-handed | 78% | 83% | 86% | 83% |
Multiplex family | 35% | 6% | 0% | 100% |
Medication free | 27% | 58% | 83% | No data |
Task performance | 69–100 | 78–100 | 75–100 | 84–100 |
95 ± 7 | 96 ± 6 | 96 ± 6 | 98 ± 4 |
Experimental procedure
EEG recording and analysis
Statistical analysis
Results
Reappraisal of ERP abnormalities in ASD based on previously published studies
New data collection
Effects of stimulus type and orientation
N170 latency | N170 amplitude | P1 latency | P1 amplitude | P1/N170 slope | |
---|---|---|---|---|---|
General effects | |||||
Type | ++++ | ++++ | ++++ | +++± | ++++ |
++=± | ++++ | ==== | ++++ | ++++ | |
Orientation | ++++ | ++++ | ++++ | ++++ | ++++ |
++++ | =±++ | +++± | ==== | ==== | |
Hemisphere | ==== | ==== | ++++ | ==== | ++++ |
==== | ==== | ==== | ==== | ==== | |
Type X orientation | ==±= | ==== | ++++ | ++++ | ++++ |
++=± | ==++ | ==== | ==== | ±±== | |
Type X hemisphere | +++= | ++++ | ==== | ==±= | ±+++ |
==== | ==== | ==== | ==== | ==== | |
Orientation X hemisphere | ==±= | ++++ | ==== | ±=±+ | ±=±= |
==== | ==== | ==== | ==== | ==== | |
Type X orientation X hemisphere | ==== | ==== | ===+ | ===± | ==== |
==== | ==== | =±=+ | ==== | ==== | |
Group differences (ASD/US/UC) | |||||
Group | ==== | ==== | ===± | ==== | ==== |
Type X group | =±== | ==== | ==== | ±=== | ==== |
Orientation X group | ==== | ===+ | ==== | ==== | =±== |
Hemisphere X group | ==== | ==== | ==== | ===± | ==== |
Type X orientation X group | ==== | ==== | ==== | ==== | ==== |
Type X hemisphere X group | ==== | ==== | ==== | ±=== | ==== |
Orientation X hemisphere X group | ±=== | ==== | ==== | ==== | ==== |
Type X orientation X hemisphere X group | ==== | ==== | ==== | ==== | ==== |
Group comparisons
Hypotheses | Reference scheme | Group difference, t/p/d | Main effect, t/p | |||||
---|---|---|---|---|---|---|---|---|
ASD vs. UC | UC vs. US | US vs. ASD | ASD | UC | US | UF | ||
1. Face over objects superiority effect (difference between N170 latency for face and houses upright at P8) | Nose | 1.12/.13/.22 | .42/.34/.09 | 1.56/.06/.34 | .91/.18 | 2.52/< .01 | 3.52/< .01 | 1.40/.09 |
REST | 1.43/.08/.28 | .72/.23/.16 |
1.92/.03/.42
| 1.88/.03 | 4.64/< .01 | 4.07/< .01 | 2.28/.02 | |
Average |
2.50/< .01/.49
| .88/.19/.19 | 1.53/.06/.34 | 1.68/.05 | 7.10/< .01 | 4.85/< .01 | 2.86/< .01 | |
Vertex | 1.25/.10/.25 | .23/.41/.05 | 1.05/.15/.23 | 1.93/.03 | 4.03/< .01 | 4.6/< .01 | 2.03/.03 | |
2. Face inversion effect on P1/N170 slope (difference between face upright and face inverted at P8) | Nose | .84/.20/.17 | .39/.34/.08 | .48/.31/.10 | 4.17/< .01 | 5.10/< .01 | 5.99/< .01 | .99/.17 |
REST |
1.95/.02/.39
| 1.22/.12/.26 | .68/.25/.10 | 3.72/< .01 | 6.07/< .01 | 4.59/< .01 | 1.14/.14 | |
Average | 1.32/.09/.26 | 1.44/.08/.31 | .06/.47/.01 | 3.02/< .01 | 6.92/< .01 | 4.03/< .01 | .53/.30 | |
Vertex | 1.46/.07/.29 | 1.28/.10/.28 | .24/.41/.05 | 3.03/< .01 | 6.58/< .01 | 3.89/< .01 | .72/.24 | |
3. Post hoc follow-up*: Inversion effect on N170 amplitude (difference between upright and inverted stimuli—face and houses—at P8/P7) | Nose | .19/.85/.04 | .30/.77/.06 | .09/.93/.02 | 2.60/.01 | 3.62/< .01 | 2.87/.01 | .99/.34 |
REST | 1.64/.10/.32 | .44/.66/.09 | 1.03/.31/.23 | 3.25/< .01 | 4.66/< .01 | 1.23/.22 | .28/.78 | |
Average |
2.11/.04/.42
| 1.79/.08/.39 | .24/.81/.05 | 1.99/.05 | 3.33/< .01 | 1.42/.16 | .61/.55 | |
Vertex |
3.11/< .01/.62
|
1.98/.05/.43
| .92/.36/.11 | .39/.70 | 3.79/< .01 | 1.99/.05 | .15/.88 |