Caudate Hyperintensities in Elderly Depressed Patients With Neuroleptic-Induced Parkinsonism

Elderly patients are particularly sensitive to the neurologic side effects of psychotropic medications. This increased sensi tivity may be related to brain structural changes associated with aging. In this pilot study, the authors report on the oc currence of caudate hyperintensities, using brain magnetic resonance imaging, in seven elderly depressed subjects who developed neuroleptic-induced parkinsonism. Caudate hyperintensities were not observed in any of the seven healthy elderly controls examined. These results suggest that caudate hyperintensities may render some elderly depressed pa tients susceptible to neuroleptic-induced parkinsonism. (J Geriatr Psychiatry Neurol 1991;4:86-89)

Subcortical hyperintensities on brain magnetic resonance imaging: A comparison between late age onset and early onset elderly depressed subjects

Subcortical structural changes have been reported to occur in some elderly subjects with late age onset depression. Given the association between diseases affecting subcortical structures and affective disorders, this suggests that these structural changes may be involved in the etiology of late age onset depression in some patients. With the advent of Brain Magnetic Resonance Imaging (MRI), “in vivo” analysis of these subcortical structures is now possible. The authors report a higher occurrence of caudate (60% vs. 11%) and large deep white matter hyperintensities (60% vs. 11%) in late age onset elderly depressed subjects compared with early onset elderly depressed subjects. These results suggest that late age onset depression may be mediated by caudate and white matter structural changes in some patients

Hyperintense lesions on magnetic resonance images in bipolar disorder

Background: To examine the magnetic resonance (MR) images of bipolar patients across a wide age range for the presence of hyperintense lesions compared to age- and gender-matched control subjects. Methods: Consecutive admissions to a mood disorders unit over a 2-year period were evaluated retrospectively for the presence of bipolar disorder by DSM-III-R criteria and whether they received an MR scan. Bipolar patients (n = 70, mean age = 49.9 ± 19.7 years) were age- and gender-matched to control subjects (n = 70, mean age = 53.2 ± 18.1 years) and the MR scans were rated to assess for the presence of hyperintensites. Results: Compared to control subjects, the bipolar patients demonstrated hyperintense lesions in the subependymal region, subcortical gray nuclei, and the deep white matter. Conclusions: Hyperintense lesions in bipolar patients are found in both the subcortical white matter and gray nuclei and may play an important role in the etiology of bipolar illness

Control and Elimination of Cracking of AlGaN Using Low-Temperature AlGaN Interlayers

We demonstrate that the insertion of low-temperature (LT) AlGaN interlayers is effective in reducing mismatch-induced tensile stress and suppressing the formation of cracks during growth of AlGaN directly upon GaN epilayers., Stress evolution and relaxation is monitored using an in-situ optical stress sensor. The combination of in-situ and ex-situ. characterization techniques enables us to determine the degree of pseudomorphism in the interlayers. It is observed that the elastic tensile mismatch between AlGaN and GaN is mediated by the relaxation of interlayers; the use of interlayers offers tunability in the in-plane lattice parameters