Impaired Visuospatial Processing in
Young Adult Female Fragile X
Premutation Carriers and Emerging
Trends in Children
Yingratana Bella McLennan, Ling Wong, Naomi
Goodrich-Hunsaker, Danielle Harvey, Flora Tassone,
Susan Rivera, Tony J. Simon
13th International Fragile X Conference, Miami 2012
July 26, 2012
FMR1 Gene Variation
FMR1 gene can be found on the long arm of
the X chromosome at position 27.3
Female Premutation
Prevalence of premutation:
•
1 in 113-259
females
•
1 in 260-813 males
•
Female Premutation
Prevalence of premutation:
•
1 in 113-259
females
•
1 in 260-813 males
•
Female Premutation
Prevalence of premutation:
•
1 in 113-259
females
•
1 in 260-813 males
•
How do female fragile X premutation carriers perform in visual
tasks involving spatial information (visuospatial processing)?
How do female fragile X premutation carriers perform in visual
tasks involving spatial information (visuospatial processing)?
How do female fragile X premutation carriers perform in visual
tasks involving spatial information (visuospatial processing)?
How do female fragile X premutation carriers perform in visual
tasks involving spatial information (visuospatial processing)?
How do female fragile X premutation carriers perform in visual
tasks involving spatial information (visuospatial processing)?
How do female fragile X premutation carriers perform in visual
tasks involving spatial information (visuospatial processing)?
How do female fragile X premutation carriers perform in visual
tasks involving spatial information (visuospatial processing)?
How do female fragile X premutation carriers perform in visual
tasks involving spatial information (visuospatial processing)?
Psychomotor Speed
Female Motor Reaction Times
*
‣
Adult female fXPCs show
faster psychomotor
speed compared to HCs
Female Oral Reaction Times
Visuospatial Processing Tasks
Magnitude Comparison
Enumeration Verbal
(Distance Effect Task)
(Numerical Spatial Attention Task)
Magnitude Comparison
Magnitude Comparison Task
“Which of the two blue bars is longer?”
‣
Distances between the 2 bars
vary between 1-7cm in length
‣
The greater the difference in
lengths, the easier it is to
judge which bar is longer
‣
Performance accuracy goes
down as the differences in
lengths become smaller
Magnitude Comparison Results
*
‣
‣
**
*
Female carrier adults (20-42 years old) show significant differences in
reaction times after their enhanced psychomotor speed was accounted for
but had no significant difference in error rates as compared to controls
However, female carrier children (7-15 years old) show no significant
differences in reaction time and error rates as compared to controls
Magnitude Comparison: Age and CGG Effects
*
*
*
*
‣
No significant correlations were found from age in the
children or adults. ‣
However, a significant correlation was found in terms of
worse performance and CGG expansion in adult female
carriers but not in children.
Enumeration Verbal
Enumeration Verbal Task
“How many green items do you see in the red square?”
‣
Small items (1-3 items) are
effortless
‣
The answer can be perceived
at a glance without counting ‣
Subitizing effect
Enumeration Verbal Task
“How many green items do you see in the red square?”
‣
‣
‣
Large items (5-8) are more
difficult
Each individual item is
mentally separated out and
counted
Counting effect
Enumeration Verbal Results
‣
Female carrier adults (21- 42 years old) show no significant differences
in reaction times or error rates as compared to controls
‣
Female carrier children (7-15 years old) also show no significant
differences in reaction time or error rates as compared to controls
Enumeration Verbal Age and CGG Effects
*
*
*
‣
‣
*
No significant correlations were found from age in the children or adults.
However, a significant correlation was found in terms of worse
performance and CGG expansion in adult female carriers but not in
children for the counting range. The subitizing range showed no
correlation.
Summary
‣
‣
‣
Magnitude Comparison:
As a group, adult female carriers show a significant difference in
performance compared to adult female controls
Results show a positive correlation indicative of poorer performance
in detecting quantitative differences at higher CGG levels
‣
‣
‣
Enumeration Verbal: As a group, adult female carriers showed no significant differences
in performance compare to adult female controls
However, results show another positive correlation between poorer
performance on the task and increasing CGG length
‣
Conclusion: Higher CGG repeat lengths may contribute to
subtle impairments in visuospatial processing even when
there are no group differences
Thank you
‣
‣
‣
‣
Thanks to all those that participated in our study
CABIL Lab members:
‣ Naomi Goodrich-Hunsaker
‣ Ling Wong
‣ Flora Tassone
‣ Danielle Harvey
Collaborators:
‣ Johnson GadElkarim
‣ Liang Zhan
‣ Olusola Ajilore
‣ Alex Leow
Thanks to: ‣ Susan Rivera
‣ Paul Hagerman
Funding: NIDCF UL1 DE019583, NIA
‣ Randi Hagerman
RL1 AG032119, NINDS RL1
‣ John Olichney
NS062412, NIDA TL1 DA024854.
‣ The rest of the NTRI team