Cognitive and Electrophysiological Correlates of Working Memory Impairments in Neurofibromatosis Type 1.

Neurofibromatosis 1 (NF1) is a single gene disorder associated with working Memory (WM) impairments. The aim of this study was to investigate P300 event-related potential (ERP) associated with WM in NF1. Sixteen adolescents with NF1 were compared with controls on measures of WM and EEG was recorded during a WM nback task. The NF1 group showed poorer performance on measures of WM as compared to the control group. No group differences were observed in P300 amplitude at Pz, but P300 latency was shorter in the NF1 group. Topographic analyses of P300 amplitude showed group differences indicating neural processing differences in the NF1 group relative to controls, which possibly contribute to the cognitive deficits seen in this population.

Morning and evening salivary cortisol levels in patients with chronic widespread pain and those at high risk.

BACKGROUND: Hypothalamic-Pituitary-Adrenal (HPA) axis dysregulation has been implicated in chronic widespread pain (CWP); the hallmark of fibromyalgia (FM). This is the first study to compare HPA axis changes in individuals with CWP and those at high risk of symptom development. METHODS: We sought to determine differences in morning and evening salivary cortisol levels in FM (n = 19), those at-risk (n = 20) and pain-free controls (n = 17). Risk factors included non-CWP pain, somatic symptoms, illness behaviour and sleep disturbance. We conducted the study in the absence of centrally acting medication, to address limitations of previous research. RESULTS: Repeated measures ANOVA revealed significant main effects of group (p = 0.003), and time of day (p = 0.002), with no significant interaction. Cortisol levels were higher in FM (p = 0.027) and at-risk (p = 0.003) groups, compared to controls, but there was no significant difference between FM and at-risk groups. The main effect of group remained significant with sleep problems (p = 0.021) and life events (p = 0.007), but was not significant with anxiety (p = 0.076) or depression (p = 0.098) scores as covariates. With sleep problems as a covariate, cortisol levels remained significantly higher only in the at-risk group (p = 0.017). CONCLUSIONS: This study indicates elevated salivary cortisol in FM and those at high risk, and identifies anxiety, depression and sleep problems as potential contributing factors. The results shed light on the dynamic relationship between stress, mood and sleep disorders and the brain's resilience to pain. SIGNIFICANCE: This study examines neurobiological changes in chronic widespread pain and high risk individuals. One strength of the study is the absence of centrally acting medication. We found high salivary cortisol common to Fibromyalgia and those at risk and identified contributing factors. Our results offer insight into the early mechanistic changes underlying Fibromyalgia development and open up possibilities for early diagnosis and prevention.