How Turner's Syndrome Affects Learning

• Journal Listing
• HHS Author Manuscripts
• PMC2742423

Int Congr Ser. Author manuscript; available in PMC 2009 Sep 11.

Published in last edited form as:

PMCID: PMC2742423

NIHMSID: NIHMS129158

The cerebral phenotype of Turner syndrome: Specific learning disabilities

Michèle Chiliad.Thousand. Mazzocco

Department of Psychiatry and Behavioral Sciences, Johns Hopkins University Schoolhouse of Medicine, USA, Department of Population and Family Health Sciences, Johns Hopkins Bloomberg Schoolhouse of Public Health, United states, Math Skills Evolution Project, Kennedy Krieger Establish, U.s.a.

Abstract

Global descriptors of the cognitive phenotype of Turner syndrome are well established and are thus commonly referred to. For example, Turner syndrome is a proposed etiology of the nonverbal learning disability – because of reported relative strengths in verbal skills, and relatively weaker nonverbal skills – particularly in arithmetic, select visuospatial skills, and processing speed. This contour is observed throughout and beyond the school historic period years. Reliance on this gross level description of the cerebral profile (due east.g., nonverbal learning disability) may be helpful as a starting point when determining whether an private with Turner syndrome has educational needs, but it carries limited applied significance when determining the specific nature of these needs. The limitations stalk from the fact that the severity of the cerebral contour is highly variable among individuals with Turner syndrome; that the "nonverbal" difficulties are specific rather than widespread; and that whatsoever individual with Turner syndrome may also manifest cerebral characteristics independent of Turner syndrome. In view of the increased run a risk for specific cognitive difficulties, a detailed assessment prior to the onset of formal schooling (or at the time of diagnosis, when diagnosis occurs after v years of historic period) tin play an important role in determining school readiness and potential need for educational support among individual girls with Turner syndrome.

Keywords: Turner syndrome, Dyscalculia, Mathematics learning disability, Nonverbal learning inability

1. Introduction

That Turner syndrome is associated with a cognitive phenotype is not news. Shaffer's [ane] initial report of the cognitive phenotype was followed past subsequent studies replicating and expanding upon his, and afterwards Waber's [two], findings that Verbal IQ scores are significantly higher than Operation IQ scores amongst girls with Turner syndrome. This "5–P separate" is now considered a authentication of the Turner syndrome phenotype. Indeed, results from studies conducted over the last iv decades have demonstrated remarkable consensus in this finding. Yet this consensus does non mean, as it may exist misinterpreted to indicate, that all girls with Turner syndrome will show the phenotype, or that all girls with Turner syndrome who take this profile will have comparable degrees of relative verbal strengths and nonverbal weaknesses. Moreover, the V–P split up does not provide sufficient specific information nearly the cerebral strengths and weaknesses, many of which researchers nonetheless do non fully sympathise.

Enquiry goals over recent years have included efforts to fine-tune the description of the cognitive phenotype for Turner syndrome. Group information support the notion of relatively strong language skills, although this language strength is non global; there is testify that oral fluency skills are dumb [2,three] despite average to above average performance on nearly other verbal tasks. Similarly, relatively weaker skills in mathematics, visuospatial skills, and executive functions are not global within each of those domains. As such, reliance on a wide general descriptor of this profile (such as nonverbal learning inability) diminishes the accent on more specific characteristics. As such, the use of an umbrella term can be of limited practical significance when dealing with an individual who has Turner syndrome. In fact, the severity of the cerebral profile can be highly variable amongst individuals with Turner syndrome; too, reference to "nonverbal" difficulties is global whereas, among girls with Turner syndrome, some nonverbal difficulties are specific rather than widespread.

The full story of the phenotype deserves a more detailed summary than that of the 5–P split and nonverbal learning inability. In the review that follows, the story begins with an account of the phenotypic variability seen across individuals with Turner syndrome, even in the IQ score distribution and discrepancy. Following a review of IQ scores, I review results of current efforts to further specify the cognitive deficits in mathematics, visuospatial, and executive office skills, and and then briefly discuss the implications of findings to date for individuals with Turner syndrome.

2. IQ scores: just the first of the story

Turner syndrome typically leads to a slight subtract in scores of overall intelligence, except in cases of mental retardation associated with a band chromosome karyotype [14]. The ring karyotype is infrequent, so about girls with Turner syndrome have full scale IQ scores that are well within the boilerplate range, unremarkably distributed, and differ but slightly from scores observed in the general population. The data summarized in Table 1 reflects the minimal caste to which full scale IQ scores are affected by Turner syndrome, as reported in a sample of studies that have been carried out within the last 40 years.

Table 1

IQ scores from a sample of studies of Turner syndrome from 1962 to present

Written report	Due north	Age (years)	IQ range	IQ grouping [mean (S.D.)]
Alexander et al. [iv]	eighteen	10–24	74–130	101.0	Not reported
Elliott et al. [5]	6	11–xv	70–126	99.0	(14.7)
Inozemtseva et al. [6]	xv	8–19	71–120	98.3	(xv.2)
Keysor et al. [7]	xi	12–20	65–126	96.5	(xviii.0)
Mazzocco [viii]	29	5–16	72–135	95.0	(13.5)
Mazzocco et al. [9]	25	seven–eleven	64–136	102.half-dozen	(14.five)
Pennington et al. [10]	10	Mean=23	81–106	96.vii	(7.4)
Rovet et al. [11]	45	seven–xvi	Not reported	94.5	(16.8)
Russell et al. [12]	fifty	vii–xvi	Not reported	92.7	(thirteen.5)
Shaffer [one]	20	5–30	Non reported	97.7	(10.5)
Temple and Carney [13]	15	8–12	74–130	95.0	Not reported

Additional data that demonstrate the effects of Turner syndrome on intelligence are drawn from our comparing of IQ scores of girls with Turner syndrome with the IQ scores obtained from the mother of each daughter. The scores that appear in Fig. 1 are from girls who have participated in my research program, and who (equally a grouping) are described in greater item elsewhere [15,16]. Scores in Fig. 1 are express to those of girls for whom Wechsler scores were obtained for both her and her biological female parent. [Although paternal IQ was of equal involvement to maternal IQ, IQ data were not available from a sufficient number of fathers to include in this comparison.] In view of the well established heritability of intelligence [17], we would expect these pairs of female parent–girl scores to be quite similar to one another. This is precisely the pattern observed in Fig. 1: the variations in full calibration IQ scores amidst girls with Turner syndrome parallels the variation observed in their own mothers (who, of course, practise non have Turner syndrome). Note that all of the IQ scores included in Fig. 1 fall within the boilerplate range of 85 to 115, that many are above average, and that the girls' scores – while lower than the mothers' scores on boilerplate – vary with regard to both the magnitude and management of the mother–child discrepancy. Information technology is clear from Fig. i that mother's scores partially predict girl scores.

Full scale IQ scores of twenty individual girls with Turner syndrome and their own mothers. The paired set of data points appears in order of smallest to largest discrepancy between mothers (▲) and their ain daughters (●). The girls ranged in age from 7 to 10 years at the fourth dimension of their IQ assessment.

Full scale IQ scores reveal little nigh the Turner syndrome phenotype. The specificity reported over decades of enquiry studies is in Exact IQ (VIQ) vs. Functioning IQ (PIQ) differences. When comparing VIQ and PIQ scores of girls with Turner syndrome to their own mothers, it is credible where the specific cognitive phenotypic features emerge. As seen in Fig. two, in that location is no consistent divergence between mother and daughter VIQ scores, for either the direction or magnitude of the mother–daughter discrepancy. For PIQ scores, the direction is consequent: girls with Turner syndrome score at the same level or below that of their mothers, never higher than their mothers equally does sometimes occurs on the VIQ scale (although not at a level that is statistically significant). The difference in mother–child discrepancies cannot be attributed to age differences, because both sets of scores are age-referenced against published normative information [18].

Verbal (VIQ) and Operation IQ (PIQ) scores of twenty private girls with Turner syndrome and their ain mothers. The paired set of data points appears in order of smallest to largest discrepancy between mothers (▲) and their ain daughters (●).

Despite the consistency in direction of the discrepancy for female parent vs. child PIQ score, there certainly is no consistency in the magnitude of the discrepancy. Although scientists and clinicians well sympathize the variability indicated past standard deviation values that typically (but practice non always) accompany reported means, how oft is this information conveyed when describing the cerebral phenotype associated with Turner (or the anticipated cerebral phenotype) to the parent of an individual with a diagnosis of Turner syndrome? Fig. 3 depicts the discrepancy between VIQ and PIQ scores among the girls whose data also appear in Figs. i and ​ 2. It is apparent, from Fig. three, that the extent to which girls with Turner syndrome accept weaker nonverbal vs. verbal skills varies from basically no difference to a remarkable and substantial departure of 40 points. This is office of the missing piece of the story of the Turner syndrome phenotype. Thus, when carrying information most the Turner syndrome cerebral phenotype to individuals, their families, and their teachers, an authentic discussion of the "V–P dissever" would include reference to the consistency in direction of the VIQ–PIQ discrepancy, the inconsistency in magnitude of this discrepancy, and the full range of manifestations of the discrepancy beyond individuals. It is as of import to highlight the possibility of a remarkable discrepancy (more than than two standard deviations, or forty points) every bit it is to bespeak the possibility of no discrepancy. The anticipated discrepancy for an individual should be discussed merely when information technology has been assessed using standardized testing.

Verbal and Functioning IQ score discrepancies vary across private girls with Turner syndrome.

The 5–P split is the finding that has led to the frequent reference to nonverbal learning inability in girls with Turner syndrome. Do all girls with Turner syndrome accept a learning disability, and if and so, in what areas?

three. Mathematics disabilities and difficulties

3.1. Mathematics achievement

A chief component of a nonverbal learning disability is difficulty with mathematics [19]. Difficulty with mathematics is as well reported for school historic period girls with Turner syndrome [8,11,15,16,20]. In view of the lack of consensus regarding what cognitive features underlie mathematics difficulties or disabilities [21], it is not surprising that the global description of poor mathematics performance is an bereft caption for why girls with Turner syndrome have difficulty with mathematics, or what aspects of mathematics are most challenging for girls with Turner syndrome. That the difficulties are present is undeniable, based on group data. For example, in an ongoing longitudinal study of the Turner syndrome phenotype, nosotros establish that scores on measures of Verbal reasoning (analogous to a Exact IQ score), obtained from the Stanford Binet Fourth Edition (SB-4) [22] are significantly higher than scores reported for the Test of Early Mathematics Ability 2d Edition (TEMA-2; [23]), even at kindergarten or outset course [15]. Among these young master school age students, the discrepancy between verbal reasoning and TEMA-ii scores was significant for the group of girls with Turner syndrome (n = xx), Wilcoxon tied Z value = −3.24, p=.001, just not for girls in an age- and form-matched comparison group, p =.73. Elsewhere nosotros take noted the consistency with which the direction of this difference is observed, and the relative consistency in the overall magnitude of the discrepancy between these two scores [8,16].

iii.ii. Mathematics disability

The verbal vs. mathematics performance difference implicates lower math vs. verbal skills, but it does non necessarily implicate poor math performance considering perhaps girls with Turner syndrome – as a grouping – have above boilerplate verbal reasoning skills relative to historic period appropriate mathematics ability. This explanation fails to surface from published studies. Instead, the prevalence of mathematics learning disability (MLD) amid girls with Turner syndrome exceeds the estimated prevalence in the general population (∼6% to 10%). Rovet [xx] institute that 55% of the 7- to sixteen-yr-old girls with Turner syndrome who participated in her study met criteria for MLD, vs. 7% of her comparing group. Similar rates have been reported for girls in chief school, for which 43% of girls with Turner syndrome and 10% of girls without Turner syndrome meet criteria for MLD [fifteen].

Coming together criteria for MLD at one point in fourth dimension does not definitively mean that the kid volition continue to meet these criteria. Persistence over time is an important benchmark for establishing MLD. Based on recent findings, when girls with Turner syndrome run across criteria for MLD in their early on school years, evidence of MLD is more than likely to persist than to misemploy by the end of third grade [xvi]. The recurrence rate between kindergarten and grade three is equally high for girls with Turner syndrome as for children from the general population [16]. Although the persistent rates do non differ significantly betwixt these 2 participant groups, information technology is worth noting that the reported persistence rate for Turner syndrome (84%) emerges over two visits during 4 years of chief school (grades kindergarten to 3), whereas the rate for the general population (seventy%) is based on four visits over four years. That is, children with Turner syndrome had fewer opportunities to demonstrate persistently meeting criteria for MLD than did children from the comparison group, and yet the frequency of persistence was as loftier (if not college) than that for children without Turner syndrome [16].

It is thus well established that individuals with Turner syndrome are at higher run a risk for MLD, and that, as a grouping, these individuals have difficulty with mathematics. What is the source of these difficulties, and what are the sources that have been ruled out?

First, the observed math deficits reported for girls with Turner syndrome appear to be unrelated to difficulty in number sense or overall calculation accuracy in females with Turner syndrome [16,24–26]. Indeed, poor math achievement occurs despite relative strengths in simple arithmetic, number comprehension and production, number comparison and estimation accurateness [24,26].

2d, visuospatial skills too appear to be unrelated to mathematics difficulties, despite reported deficits in visuospatial skills in girls with Turner syndrome (described below). Particular analyses and correlational studies have been carried out to evaluate the potential link between math and spatial skills in school age girls with Turner syndrome. The item analyses have failed to reveal difficulty on specific, spatially oriented problems (e.g., geometry, shape matching) amid girls with Turner syndrome [11,15,sixteen], although detail analyses take differentiated other populations from their peers (such as girls with fragile Ten syndrome [fifteen,16]. An fault assay written report also failed to identify more than spatially relevant math adding errors in girls with Turner syndrome (such equally more alignment errors), relative to their peers, except when the peer group was girls with delicate X [8]. Correlational studies, which take demonstrated a positive association between math operation and several visuospatial skills among girls with fragile X syndrome take not revealed consistent support for such associations among girls with Turner syndrome [eight,9]. Together, these findings back up Rovet's [11] conclusion that arithmetics deficits in girls with Turner syndrome are contained of spatial skills performance levels.

In the absence of poor number sense or underlying spatial deficits, what does narrate math functioning in girls with Turner syndrome? Processing speed appears to play a pregnant part, as girls with Turner syndrome are slower on arithmetic fact retrieval, and on response times during calculations [24,25,27] peculiarly for larger addends [26,27]. Response times are slower on estimation problems [24,28], even for very small quantities that typically developing children tend to process instantly, or subitize, rather than count [24]. More research is needed to determine the nature of these processing deficits, and whether or how specific aspects of mathematics are differentially challenging for girls with Turner syndrome as mathematics curriculum demands increase during the schoolhouse historic period years.

iv. Spatial skills, executive functions, and attention

four.1. Visuospatial deficits

Despite reports of visuospatial deficits in Turner syndrome, several attempts to specify deficits in merely a subset of visuospatial skills have failed [2,29]. Relative to their peers, girls with Turner syndrome have difficulty with both visuoperception and visuo-constructional tasks [xiii]. Visuoperception deficits are credible on object identification and location identification tasks, and yet announced associated with poor visual working memory [29]. The global deficits should not be taken to mean that all visuospatial skills are impaired; in fact, in our work we have not found differences in accurateness on measures of shape matching, or in capturing the gestalt of visual arrays on tests of visual short term memory [9]. However, like others, we have found less authentic performance on tests of object identification, object location, and visual memory for objects; and slower response times on select visuospatial tasks [9]. Others accept also reported slower response times on visual spatial tasks by girls with Turner syndrome [29].

four.two. Working retention and executive function

Information technology is unclear whether visual working retentiveness difficulties and slowed response times are further reflection of the processing speed deficits reported in both early and recent studies [two,3]. In ane recent report of working memory and executive function, we administered a timed task with varying degrees of working memory loads. Nosotros found that although third graders with Turner syndrome took significantly longer than their peers to complete a basic naming job, response times did not differ significantly when working memory demands were increased: response times increased with working retentiveness demands, but for both participant groups. Even so, the girls with Turner syndrome fabricated more than twice equally many errors as their peers on the naming tasks, when working retentiveness demands increased [30]; this ways that for them, the increase in response time beyond tasks did not lead to maintaining a relatively high degree of accuracy, as it did for the peer comparison grouping. In other words, girls with Turner syndrome were less accurate despite taking equally much fourth dimension to complete the timed task every bit did their peers.

Temple and colleagues [31] likewise reported working retentiveness deficits in viii to 12 year olds with Turner syndrome. They establish that girls with Turner syndrome were impaired on executive function tasks that, similar the chore reported on above, involved speeded responses. However, they plant no deficits on planning or set maintenance tasks.

4.3. Attention deficits in Turner syndrome

Early studies of attention skills in girls with Turner syndrome failed to reveal either widespread attention difficulties or specific deficits in sustained attention or impulsivity [32]. Yet the variability in attending and impulsivity observed in girls with Turner syndrome was interpreted as an indicator of atypical attending deficit disorder [33]. This notion has received additional support from a recent study that showed both an increased incidence of attention-arrears hyperactivity disorder (ADHD; 24%), and a higher frequency of the hyperactive/impulsive subtype of ADHD, in girls with Turner syndrome vs. children in the general population [12]. Information technology remains to be seen whether ADHD in girls with Turner syndrome has like neuropsychological profiles and treatment response patterns to those reported for children with typical ADHD. Handling implications are complicated by the growth retardation that occurs with Turner syndrome.

5. Conclusions: the story in its proper context

The Turner syndrome cognitive phenotype is well described at a global level. The cognitive phenotype is characterized past specific deficits in visuospatial and executive skills, visual working retentivity, and mathematics. Response fluency (long response times) is a remarkably persistent finding across tasks. We can meliorate upon this phenotype description by specifying the show to date: Bear witness for highly variable levels of phenotype severity, and for specific difficulties within each of several cognitive domains; findings that phenotypic features sally by kindergarten if non sooner, and that the deficits that practice sally persist over time [16].

Several relevant bodies of inquiry were not included in this brief review. For example, the cognitive features reviewed herein are aligned with results of neuroimaging studies, such every bit findings of parieto-occipital and basal ganglia abnormalities [34–36] including parietal and occipital–parietal hypometabolism that is observed among girls with Turner syndrome who also take learning difficulties [five]. Moreover, there is evidence that heterogeneity in the cerebral deficits observed in Turner syndrome are related to gene mapping [37] or specific karyotypes [31], and that select deficits prove improvement with estrogen therapy [38]. In that location is an ongoing controversy regarding potential imprinting (parent of origin effects) on the Turner syndrome cognitive phenotype. For example, whereas Skuse reports imprinting effects on social knowledge [39], Russell and colleagues found no furnishings of imprinting on ADHD behaviours [12]. Future studies will serve to further address each of these factors and to contribute to efforts to delineate the processes that underlie the cerebral phenotype. Also, as most studies of the cognitive phenotype are based on cross exclusive studies, questions remain concerning the developmental trajectory of the cognitive phenotype associated with Turner syndrome. We have begun to study on longitudinal studies [sixteen] and will keep this line of research.

There are important implications to be drawn from the existing data. At that place is an increased risk for specific cerebral difficulties, including mathematics learning disability and ADHD, but not in all individuals with Turner syndrome. Math difficulties do appear among nearly girls with Turner syndrome, and manifestation of these and other cognitive difficulties occur every bit early as kindergarten (if not earlier). In social club to promote appropriate early intervention, screening is advisable for all girls with Turner syndrome, particularly prior to formal schooling equally a means to determine school readiness and potential needs for educational back up. Both longitudinal and cantankerous sectional studies suggest that the cognitive difficulties associated with Turner syndrome persist throughout development, so educational support needs may go on well across the elementary schoolhouse years. Amid the most frequent findings across studies is slowed response times, every bit seen on tests of oral fluency, arithmetic, visuospatial processing, and working memory. Thus, for many girls with Turner syndrome, adjusting time demands on school tasks may be a necessary means by which to assess level of conceptual mastery in a given field of study area.

In view of the variability observed in the Turner syndrome cognitive phenotype, care should be taken to individualize contour descriptions and recommendations for intervention whenever applying research findings to an individual. Such efforts volition too aid in the identification of learning difficulties non associated with Turner syndrome, such as dyslexia, that may be overlooked simply considering they fail to be included in the global descriptions that are subject to misinterpretation when applied to individuals.

Acknowledgments

I would similar to acknowledge the support of the participants and their families, research coordinators Gwen F. Myers and Kathleen Devlin, and research assistant Elizabeth Romanow. This work was supported by NIH grant HDR0103461-01-09 awarded to Dr. Mazzocco.

References

1. Shaffer JW. A specific cognitive deficit observed in gonadal aplasia (Turner's syndrome) J Clin Psychol. 1962;18:403–406. [PubMed] [Google Scholar]

two. Waber DP. Neuropsychological aspects of Turner's syndrome. Dev Med Kid Neurol. 1979;21(ane):58–lxx. [PubMed] [Google Scholar]

3. Temple CM. Oral fluency and narrative production in children with Turner's syndrome. Neuropsychologia. 2002;xl(8):1419–1427. [PubMed] [Google Scholar]

4. Alexander D, Ehrhardt AA, Money J. Defective figure drawing, geometric and human being, in Turner's syndrome. J Nerv Ment Dis. 1966;142(2):161–167. [PubMed] [Google Scholar]

5. Elliott TK, et al. Positron emission tomography and neuropsychological correlations in children with Turner's syndrome. Dev Neuropsychol. 1996;12(3):365–386. [Google Scholar]

six. Inozemtseva O, et al. Syntactic processing in Turner's syndrome. J Child Neurol. 2002;17:668–672. [PubMed] [Google Scholar]

7. Keysor CS, et al. Physiological arousal in females with fragile X or Turner syndrome. Dev Psychobiol. 2002;41(ii):133–146. [PubMed] [Google Scholar]

8. Mazzocco MMM. A procedure approach to describing mathematics difficulties in girls with Turner syndrome. Pediatrics. 1998;102(2 Pt 3):492–496. [PubMed] [Google Scholar]

9. Mazzocco MMM, Bhatia NS, Lesniak-Karpiak G. Visuospatial skills and their clan with math operation in girls with frail X or Turner syndrome. Child Neuropsychol. 2006;12(2):87–110. [PubMed] [Google Scholar]

10. Pennington BF, et al. The neuropsychological phenotype in Turner syndrome. Cortex. 1985;21(3):391–404. [PubMed] [Google Scholar]

11. Rovet J, Szekely C, Hockenberry MN. Specific arithmetics calculation deficits in children with Turner syndrome. J Clin Exp Neuropsychol. 1994;16(vi):820–839. [PubMed] [Google Scholar]

12. Russell HF, et al. Increased Prevalence of ADHD in Turner Syndrome with no prove of imprinting effects. J Pediatr Psychol. in printing. [PubMed] [Google Scholar]

13. Temple CM, Carney RA. Patterns of spatial performance in Turner'due south syndrome. Cortex. 1995;31(1):109–118. [PubMed] [Google Scholar]

14. Van Dyke DL, et al. Ullrich–Turner syndrome with a small ring X chromosome and presence of mental retardation. Am J Med Genet. 1992;43:996–1005. [PubMed] [Google Scholar]

15. Mazzocco MMM. Math learning disability and math LD subtypes: evidence from studies of Turner syndrome, fragile X syndrome, and neurofibromatosis type 1. J Learn Disabil. 2001;34(half dozen):520–533. [PubMed] [Google Scholar]

xvi. Tater MM, et al. Mathematics learning inability in girls with Turner syndrome or frail X syndrome. Brain Cogn. 2006;61(ii):195–210. [PubMed] [Google Scholar]

17. Plomin R, et al. Deoxyribonucleic acid markers associated with high versus low IQ: the IQ Quantitative Trait Loci (QTL) Projection. Behav Genet. 1994;24(2):107–118. [PubMed] [Google Scholar]

eighteen. Wechsler D. Wechsler Abbreviated Scale of Intelligence: WASI. The Psychological Corporation; San Antonio, TX: 1999. [Google Scholar]

nineteen. Rourke BP. Introduction: the NLD syndrome and the white matter model. In: Rourke BP, editor. Syndrome of Nonverbal Learning Disabilities. The Guilford Press; New York: 1995. pp. 1–25. [Google Scholar]

20. Rovet JF. The psychoeducational characteristics of children with Turner syndrome. J Learn Disabil. 1993;26(5):333–341. [PubMed] [Google Scholar]

21. Mazzocco MMM. Challenges in identifying target skills for math disability screening and intervention. J Larn Disabil. 2005;38(4):318–323. [PubMed] [Google Scholar]

22. Thorndike RL, Hagen EP, Sattler JM. Stanford–Binet Intelligence Calibration: Guide for Administering and Scoring. Fourth. The Riverside Publishing Company; Chicago, IL: 1986. [Google Scholar]

23. Ginsburg HP, Baroody AJ. Examination of Early on Mathematics Power. Second. PRO-ED; Austin, TX: 1990. [Google Scholar]

24. Bruandet M, Molko Northward, Cohen 50, Dehaene S. A cognitive characterization of dyscalculia in Turner syndrome. Neuropsychologia. 2004;42:288–298. [PubMed] [Google Scholar]

25. Rovet J, Ireland L. Behavioral phenotype in children with Turner syndrome. J Pediatr Psychol. 1994;19(six):779–790. [PubMed] [Google Scholar]

26. Temple CM, Marriott AJ. Arithmetical ability and disability in Turner'south syndrome: a cognitive neuropsychological analysis. Dev Neuropsychol. 1998;14(1):47–67. [Google Scholar]

27. Molko N, et al. Functional and structural alterations of the intraparietal sulcus in a developmental dyscalculia of genetic origin. Neuron. 2003;40(4):847–858. [PubMed] [Google Scholar]

28. Butterworth B, et al. Linguistic communication and the origins of number skills: karyotypic differences in Turner's syndrome. Brain Lang. 1999;69:486–488. [Google Scholar]

29. Buchanan L, Pavlovic J, Rovet J. A reexamination of the visuospatial deficit in Turner syndrome: contributions of working memory. Dev Neuropsychol. 1998;14(23):341–367. [Google Scholar]

30. Kirk JW, Mazzocco MM, Kover ST. Assessing executive dysfunction in girls with fragile X or Turner syndrome using the Contingency Naming Test (CNT) Dev Neuropsychol. 2005;28(3):755–777. [PubMed] [Google Scholar]

31. Temple CM, Carney RA, Mullarkey S. Frontal lobe function and executive skills in children with Turner's syndrome. Dev Neuropsychol. 1996;12(3):343–363. [Google Scholar]

32. Williams J, Richman Fifty, Yarbrough D. A comparison of memory and attention in Turner syndrome and learning disability. J Pediatr Psychol. 1991;16(5):585–593. [PubMed] [Google Scholar]

33. Williams JK, Richman LC, Yarbrough DB. Comparison of visual–spatial performance strategy training in children with Turner syndrome and learning disabilities. J Learn Disabil. 1992;25(10):658–664. [PubMed] [Google Scholar]

34. Cutter WJ, et al. Influence of 10 chromosome and hormones on human brain evolution: a magnetic resonance imaging and proton magnetic resonance spectroscopy study of Turner syndrome. Biol Psychiatry. 2006;59(3):273–283. [PubMed] [Google Scholar]

35. Reiss AL, et al. Neurodevelopmental effects of X monosomy: a volumetric imaging study. Ann Neurol. 1995;38(5):731–738. [PubMed] [Google Scholar]

36. Irish potato DG, et al. X-chromosome effects on female brain: a magnetic resonance imaging written report of Turner's syndrome. Lancet. 1993;342(8881):1197–1200. [PubMed] [Google Scholar]

37. Ross JL, et al. The Turner syndrome-associated neurocognitive phenotype maps to distal Xp. Am J Hum Genet. 2000;67(iii):672–681. [PMC gratuitous article] [PubMed] [Google Scholar]

38. Ross JL, et al. Apply of estrogen in young girls with Turner syndrome: effects on memory. Neurology. 2000;54(1):164–170. [PubMed] [Google Scholar]

39. Skuse DH, et al. Evidence from Turner's syndrome of an imprinted Ten-linked locus affecting cerebral function. Nature. 1997;387(6634):705–708. [PubMed] [Google Scholar]

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2742423/

Posted by: mcmullenalliat.blogspot.com

Share this post