1. Effects of fetal alcohol syndrome on facial shape
Christian Peter Klingenberg
Faculty of Life Sciences University of Manchester

2. Can we quantify these facial features?
(from Wikipedia)
Can we quantify these facial features?
Can facial shape be used for diagnosis?
Are there other effects on facial shape?

3. Mutsvangwa T, Douglas TS (2007) Morphometric analysis of facial landmark data to characterize the facial phenotype associated with fetal alcohol syndrome. J Anat 210:209–220.

4. Sample sizes (individuals with complete and usable data)
Location
FAS
Controls
African Americans 9 11
Cape Town 49 54
Finland 40
North American Caucasians 14 18

5. Landmarks used in the study
This is a subset of an original landmark set designed for computing distances
Moore, E. S., Ward, R. E., Wetherill, L. F., Rogers, J. L., Autti-Rämö, I., Fagerlund, Å., Jacobson, S. W., Robinson, L. K., Hoyme, H. E., Mattson, S. N., Foroud, T. and CIFASD (2007) Unique facial features distinguish fetal alcohol syndrome patients and control in diverse ethnic populations. Alcoholism Clinical and Experimental Research 31, 1707–1713.

6. Extracting shape information: Procrustes superposition
Original landmark configurations
1. Change scale so that all configurations have the same size
2. Superposition of the centers of gravity on a single point
3. Rotation to minimize the dispersion of corresponding points

8. Shape change associated with the canonical variate 2
(Change by 5 units in positive direction: control to FAS)

9. Discriminant scores (all countries pooled)
106 / 137 correct
103 / 112 correct
Discriminant scores (all countries pooled)
Direct computation
104 / 137 correct
100 / 112 correct
Cross-validation

10. Discriminant scores (Cape Town only)
50 / 54 correct
48 / 49 correct
Discriminant scores (Cape Town only)
Direct computation
45 / 54 correct
44 / 49 correct
Cross-validation

11. Shape change associated with FAS in the Cape Town sample
(Actual difference in average shapes: control to FAS)

12. Facial shape differentiates between FAS and control groups.
Individuals can be assigned to the correct group with approximately 75% reliability or better.
Prospect: different set of landmarks, improving the coverage of midface and upper lip.

13. Discriminant scores (Finland only)
46 / 54 correct
38 / 40 correct
Discriminant scores (Finland only)
Direct computation
37 / 54 correct
30 / 40 correct
Cross-validation

14. Shape change associated with FAS in the Finnish sample
(Actual difference in average shapes: control to FAS)

15. Correction for effects of size: allometry
Single group
Two groups

16. Allometry: regression of shape on size

17. Allometric regression
Shape change for an increase of centroid size by 100mm

18. Canonical variate analysis of size-corrected shape data

19. Shape change associated with the canonical variate 2 of size-corrected shape data
(Change by 5 units in positive direction: control to FAS)

20. Discriminant scores (from size-corrected data, all countries)
Direct computation
120 / 137 correct
108 / 112 correct
Cross-validation

21. 53 / 54 correct
49 / 49 correct
Discriminant scores (Cape Town only, after size correction by pooled within- group regression)
Direct computation
51 / 54 correct
49 / 49 correct
Cross-validation

22. Shape change associated with FAS in the Cape Town sample (after size correction by pooled within-group regression)
(Actual difference in average shapes: control to FAS)

23. 54 / 54 correct
40 / 40 correct
Discriminant scores (Finland only, after size correction by pooled within- group regression)
Direct computation
51 / 54 correct
40 / 40 correct
Cross-validation

24. Shape change associated with FAS in the Finnish sample (after size correction by pooled within-group regression)
(Actual difference in average shapes: control to FAS)

25. Size-correction by pooled within-group regression of shape on size greatly increases the performance of discriminant functions.
Problem: this method of size correction uses information on group membership, and is therefore not applicable in the diagnostic context.
Other methods of size correction do not improve the performance of discriminant functions by much.

26. Mean asymmetry of facial shape
(Asymmetry is exaggerated 10-fold for better visibility.)

27. Discriminant scores for facial asymmetry (Cape Town only)
49 / 54 correct
40 / 49 correct
Discriminant scores for facial asymmetry (Cape Town only)
Direct computation
40 / 54 correct
35 / 49 correct
Cross-validation

28. Difference of asymmetry associated with FAS in the Cape Town sample
(Asymmetry is exaggerated 10-fold for better visibility.)

29. Discriminant scores for facial asymmetry (Finland only)
46 / 54 correct
36 / 40 correct
Discriminant scores for facial asymmetry (Finland only)
Direct computation
37 / 54 correct
25 / 40 correct
Cross-validation

30. Difference of asymmetry associated with FAS in the Cape Town sample
(Asymmetry is exaggerated 10-fold for better visibility.)

31. FAS also affects facial asymmetry.
This finding is likely to raise questions and offer new ways of research on the developmental etiology of FAS.

32. Thanks to: CIFASD and clinical study sites Tatiana Foroud
Leah Flury Wetherill
Elizabeth Moore
Richard Ward
Jeff Rogers