Evidence for Reduced Long-Term Potentiation-Like Visual Cortical Plasticity in Schizophrenia and Bipolar Disorder.

Several lines of research suggest that impairments in long-term potentiation (LTP)-like synaptic plasticity might be a key pathophysiological mechanism in schizophrenia (SZ) and bipolar disorder type I (BDI) and II (BDII). Using modulations of visually evoked potentials (VEP) of the electroencephalogram, impaired LTP-like visual cortical plasticity has been implicated in patients with BDII, while there has been conflicting evidence in SZ, a lack of research in BDI, and mixed results regarding associations with symptom severity, mood states, and medication. We measured the VEP of patients with SZ spectrum disorders (n = 31), BDI (n = 34), BDII (n = 33), and other BD spectrum disorders (n = 2), and age-matched healthy control (HC) participants (n = 200) before and after prolonged visual stimulation. Compared to HCs, modulation of VEP component N1b, but not C1 or P1, was impaired both in patients within the SZ spectrum (χ 2 = 35.1, P = 3.1 × 10-9) and BD spectrum (χ 2 = 7.0, P = 8.2 × 10-3), including BDI (χ 2 = 6.4, P = .012), but not BDII (χ 2 = 2.2, P = .14). N1b modulation was also more severely impaired in SZ spectrum than BD spectrum patients (χ 2 = 14.2, P = 1.7 × 10-4). N1b modulation was not significantly associated with Positive and Negative Syndrome Scale (PANSS) negative or positive symptoms scores, number of psychotic episodes, Montgomery and Åsberg Depression Rating Scale (MADRS) scores, or Young Mania Rating Scale (YMRS) scores after multiple comparison correction, although a nominal association was observed between N1b modulation and PANSS negative symptoms scores among SZ spectrum patients. These results suggest that LTP-like plasticity is impaired in SZ and BD. Adding to previous genetic, pharmacological, and electrophysiological evidence, these results implicate aberrant synaptic plasticity as a mechanism underlying SZ and BD.

Public Perception of a Normal Head Shape in Children With Sagittal Craniosynostosis.

: A question that remains unanswered is at what level of surgical correction does the public perceive a head shape to be "normal" or "acceptable?" For most cases of non-syndromic asymptomatic craniosynostosis, the parents desire for surgical correction is to improve the cosmetic appearance of head shape. At the time of this writing, the intraoperative surgeons' perspective of what constitutes an acceptable head shape is the target for surgical correction. In introducing an improved objectively cosmetic goal, an appropriate outcome measure would be to assess what the general public considers a normal or acceptable head shape in children with craniosynostosis. METHOD: Twenty-two unique images were presented via an online crowdsourcing survey of a severe case of non-syndromic sagittal craniosynosis gradually corrected to an age and gender matched normalized head shape. Participants were recruited via the Sick Kids Twitter account. Participants were invited to rate the head shapes as "normal" or "abnormal." RESULTS: The 538 participants completed the online survey. Participants were able to reliably and consistently identify normal and abnormal head shapes with a Kappa Score >0.775. Furthermore, participants indicated that a correction of 70% is required in order for the cranial deformity to be regarded as "normal." This threshold closely reflects a normal Cranial Index, which is a widely used morphometric outcome in craniosynostosis. CONCLUSION: Crowdsourcing provides an ideal method for capturing the general population's perspective on what constitutes a normal and acceptable head shape in children with sagittal craniosynostosis. Laypersons are able to reliably and consistently distinguish cranial deformities from a "normal" head shape. The public indicates a threshold correction of 70% in sagittal craniosynosis to regard it as a "normal" head shape.

Standardization of Cranial Index Measurement in Sagittal Craniosynostosis.

: Cranial index is a widely used 2-dimensional measure of skull form. It has traditionally been calculated as a ratio of the maximal cranial width divided by the maximal skull length. Nevertheless, the points of maximal skull length change dramatically in sagittal craniosynostosis due to variable degrees of frontal and occipital bossing. Therefore, such anatomical changes influence the calculated cranial index. METHOD: This is a retrospective comparative study of 2 methods of measuring cranial index; the traditional method that measures the skull length from glabella to opithcranion versus a modified method that measures the maximal skull length from the most anterior point of the frontal bossing to opithcranion. Cranial indices for 115 patients of radiologically and clinically diagnosed nonsyndromic sagittal craniosynostosis were calculated using both methods. Correlation and Agreements Limits were calculated for comparison between the 2 methods. RESULTS: Males constituted 74.8% (n = 86) of the total sample size with the remaining 29 participants identified as female. The mean age of the study participants was 4.8 months (range 8 days-12 months). The 2 methods were strongly correlated (r = 0.94). The Agreement Limits were calculated to be between 4.02% and 0.18%. CONCLUSION: Typical anatomical changes such as variable degrees of frontal and occipital bossing influence the accuracy of cranial index measurement in sagittal craniosynostosis. Traditional method of cephalic index measurement could underestimate the severity of scaphocephaly.