Cognitive performance in Rett syndrome girls: a pilot study using eyetracking technology

BACKGROUND

Rett syndrome (RS) is a pervasive developmental disorder with cognitive and neuromotor impairments (including loss of handiness and loss of communicative skills).

OBJECTIVE

To verify whether girls with RS use their gaze intentionally, by observing their performance in three cognitive tasks: (1) verbal instruction condition (look at picture X), (2) recognition and matching of pictures (look at the one that is the same), and (3) categorization of pictures (look at the one that is similar).

METHOD

Seven girls diagnosed with RS according to DSM-IV criteria were studied. Eyegaze technology was used to record the girls' eye movements' responses to visual stimulation.

RESULTS

The comparison of fixation time on the alternatives revealed a higher percentage (62.4%) of correct alternatives (chi(2) = 76.31; P = 0.000). Of the seven children assessed, only one did not present predominance of fixations on the correct alternatives in any one of the tasks. One did well in all tasks. Six responded correctly to all verbal instructions.

CONCLUSION

The rate of correct answers suggests that there is measurable and intentional gaze in RS girls and it can be used as a path to explore their cognitive performance.

Obsessive-compulsive disorder phenotypes: implications for genetic studies

Obsessive-compulsive disorder (OCD) clinical presentation is remarkably diverse, and can vary both within and across patients over time. This variability in the phenotypic expression has led to the hypothesis that OCD is a heterogeneous disorder and that this heterogeneity obscures the findings of clinical, natural history and treatment response studies and complicates the search for vulnerability genes. A complete understanding of what comprises OCD and the underlying etiological mechanisms will require a dramatic change in how the disorder is conceptualized. In this review, several different approaches that may represent the first steps in this reconceptualization are discussed. These approaches include (1) narrowing the phenotype to identify categorically defined more homogeneous and mutually exclusive subtypes of OCD, (2) considering OC symptom dimensions as quantitative components of the more complex OCD phenotype and (3) broadening the phenotype to include other etiologically related conditions. A combined dimensional approach within distinctive subgroups is proposed as probably the most effective in helping to identify the heritable components of OCD. By identifying heritable components of OCD, it should be possible to find genes for these separate components. The review continues with the illustration of the possible role of some epigenetic risk and protective factors in the OCD presentation and the relevance of examining associated traits and/or endophenotypes to enhance our ability to understand the genetic basis of OCD. To conclude, we discuss the variability in treatment outcome and the significance of the development of specific pharmacological and/or behavioral based therapies tailored to each of these phenotypes.

Adults with early-onset obsessive-compulsive disorder

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a clinically heterogeneous disorder with a bimodal age at onset and range of treatment outcomes. This study attempted to ascertain the importance of the age at OCD symptom onset for a better phenotypic precision. Therefore, the authors compared adult OCD patients with an early symptom onset to OCD patients with a later symptom onset.

METHOD

Forty-two adult outpatients with OCD were evaluated with semistructured interviews: 21 with symptom onset before the age of 10 (early-onset group) and 21 with symptom onset after the age of 17 (late-onset group).

RESULTS

Early onset was associated with higher scores on the Yale-Brown Obsessive Compulsive Scale, higher frequencies of tic-like compulsions, higher frequency of sensory phenomena, and a higher rate of comorbid tic disorders. The early-onset group also responded less well to treatment with clomipramine and selective serotonin reuptake inhibitors.

CONCLUSIONS

The results indicate that age at onset may be an important factor in subtyping OCD and that the phenotypic differences found were not restricted to childhood.

Antibodies against neural, nuclear, cytoskeletal, and streptococcal epitopes in children and adults with Tourette's syndrome, Sydenham's chorea, and autoimmune disorders

BACKGROUND

Some cases of Tourette's syndrome (TS) are hypothesized to be caused by autoantibodies that develop in response to a preceding group A beta hemolytic streptococcal infection.

METHODS

To test this hypothesis, we looked for the presence ot total and IgG antibodies against neural, nuclear, cytoskeletal and streptococcal epitopes using indirect immunofluorescent assays and Western blot techniques in three patient groups: TS (n = 81), SC (n = 27), and a group of autoimmune disorders (n = 52) and in normal controls (n = 67). Subjects were ranked after titrations of autoantibodies from 0 to 227 according to their level of immunoreactivity.

RESULTS

TS patients had a significantly higher mean rank for total antineural and antinuclear antibodies, as well as antistreptolysin O titers. However, among children and adolescents, only the total antinuclear antibodies were increased in TS patients compared to age matched controls. Compared to SC patients, TS patients had a significantly lower mean rank for total and IgG class antineural antibodies, significantly lower IgG class anticytoskeletal antibodies, and a significantly higher rank for total antinuclear antibodies. Compared to a mixed group of autoimmune disorders, the TS patients had a significantly lower mean rank for total and IgG class antineural antibodies, total and IgG class antinuclear antibodies, IgG class anticytoskeletal antibodies, and a significantly higher rank for antistreptococcal antibodies.

CONCLUSIONS

TS patients had significantly higher levels of total antineural and antinuclear antibodies than did controls. Their relation to IgG class antineural and antinuclear antibodies, markers for prior streptococcal infection, and other clinical characteristics, especially chronological age, was equivocal.

The psychiatric symptoms of rheumatic fever

OBJECTIVE

This study examined the frequency and age at onset of psychiatric disorders among children with rheumatic fever, Sydenham's chorea, or both and a comparison group.

METHOD

Twenty children with rheumatic fever, 22 with Sydenham's chorea, and 20 comparison children were assessed by means of a semistructured interview and rating scales for tic disorders and obsessive-compulsive disorder.

RESULTS

Obsessive-compulsive symptoms were more frequent in both the Sydenham's chorea and rheumatic fever groups than in the comparison group. The Sydenham's chorea group had a higher frequency of major depressive disorder, tic disorders, and attention deficit hyperactivity disorder (ADHD) than both the comparison and rheumatic fever groups. ADHD symptoms were associated with a higher risk of developing Sydenham's chorea.

CONCLUSIONS

Both the rheumatic fever and Sydenham's chorea groups were associated with a higher risk of developing neuropsychiatric disorders than the comparison group. ADHD appears to be a risk factor for Sydenham's chorea in children with rheumatic fever.

Sydenham's chorea

Sydenham's chorea (SC) is a disorder of the central nervous system (CNS) characterized by sudden, involuntary, arrhythmic, clonic, and purposeless movements. SC appears to provide a model for understanding various neuropsychiatric dysfunctions. Its relationship with attentional deficits, obsessive-compulsive symptoms (OCS) as well as movement disorders provides support for the hypothesis of the involvement of the corticostriatal loops in the pathophysiology of the disorder.