Connectivity and cognition in neuropsychiatric disorders with special emphasis on Alzheimer’s disease and Chorea Huntington

Excerpt

This issue opens with an invited review by Teipel et al. [1] discussing the use of diffusion tensor imaging (DTI) in the highly comorbid Alzheimer’s disease (AD) and affective disorders. DTI allows the examination of structural brain connectivity and until now has been widely used to investigate impairment of intracortical projection tracts, which has been hypothesized to be the basis of cognitive dysfunction. Analyses of large scale data revealed white matter abnormalities in AD. Fewer DTI studies focused on affective disorders, e.g., bipolar disorder and major depressive disorder with inconsistent results. Larger and more homogenous groups of patients would allow the detection of subtle differences and avoid false-negative results. Applying other techniques could also open new possibilities for studying the brain network. Diffusion spectrum imaging (DSI) offers better resolution than DTI, but is rarely used due to its limited availability, software requirements and long duration of analysis. More common use of DSI would improve data quality and provide better insight into the structural connectivity in neuropsychiatric diseases. Additionally, prospective studies are needed to follow-up patients with AD and mild cognitive impairment for several years. Understanding the changes that prelude the symptoms would allow early diagnosis and pre-onset therapies. In an interdisciplinary and longitudinal study, Toro et al. [2] found high total cholesterol in serum at the age of 60 to be associated with a higher risk of Alzheimer’s disease and with mild cognitive impairment at the age of 75. The APOEε4 allele, which is an important genetic risk factor for AD, did not interact with serum cholesterol. In contrast to serum, cholesterol levels in cerebrospinal fluid did not correlate with the development of symptoms. Thus, total cholesterol in serum may be suitable as an early marker to predict the risk of disease in later life. …