Effects of white matter hyperintensities on isolated executive function assessed by the Trail Making Test.

BACKGROUND: White matter hyperintensities (WMHs) on MRI are associated with cognitive dysfunction, particularly slow processing speed and executive dysfunction. However, it is not clear whether WMHs burden affects isolated executive function independent of aging when WMHs are assessed separately in periventricular hyperintensity (PVH) and deep and subcortical white matter hyperintensity (DSWMH). PURPOSE: To assess the relationship between the degree of WMHs and the performance on the Trail Making Test (TMT), which can evaluate isolated ability of set-shifting and working memory. METHODS: 74 participants who visited our memory clinic and underwent the TMT subtests (TMT-A and TMT-B) and the Mini-Mental State Examination (MMSE). All subjects performed the TMT within the time limits and their MMSE scores were 24 or higher, and they were diagnosed as having normal cognition or mild cognitive impairment. The extent of PVH and DSWMH was graded from 0 to 3 using the Fazekas scale. We obtained testing time to complete the TMT-A and TMT-B, and calculated TMT-B minus TMT-A. We performed correlation analyses between the degree of WMHs and the time measures of the TMT subtests with adjustment of age. RESULTS: Average scores of the MMSE were not different among the groups either by PVH grade or by DSWMH grade. In contrast, average time required for the TMT-A, TMT-B, and TMT-B minus TMT-A increased along with exacerbation of PVH and DSWMH grade. After the adjustment of age we found significant association between only DSWMH grade and the time difference of TMT-B minus TMT-A. CONCLUSIONS: Exacerbation of PVH and DSWMH differentially affected isolated executive functions assessed by the TMT subtests independent of age and general cognitive function.

Post-ischemic delayed expression of hepatocyte growth factor and c-Met in mouse brain following focal cerebral ischemia.

We investigated long-term changes in the expression of protein and mRNA of hepatocyte growth factor (HGF) and its receptor c-Met in mouse brain after permanent occlusion of the middle cerebral artery, by using immunohistochemistry and quantitative reverse transcription-polymerase chain reaction. HGF-immunopositive cells were observed in the periinfarct region from 4 days after occlusion, peaking at 14-28 days. The area containing HGF-immunopositive cells continued to expand until 28 days after occlusion. c-Met-immunopositive cells were observed exclusively at the periinfarct region at 7 and 14 days after occlusion. At 28 days after occlusion, there were many c-Met-immunopositive cells in the widespread periinfarct region. Triple immunohistochemical staining by using confocal laser scanning microscopy (CLSM) demonstrated that most of the HGF-immunopositive cells were localized to reactive astrocytes. The c-Met-immunopositive cells were also localized to reactive astrocytes. HGF mRNA was upregulated exclusively in the periinfarct region at 14 days. c-Met mRNA was upregulated in the periinfarct region from as late as 28 days after occlusion. Thus, HGF and c-Met show delayed expression in the periinfarct region at both protein and mRNA levels after induction of ischemia. Because HGF was recently shown to play critical roles in angiogenesis and neurotrophic activities, the temporal profiles of their expression may imply the involvement of HGF in the process of post-ischemic brain tissue repair.

Persistent but reversible coma in encephalitis.

INTRODUCTION: Nontraumatic coma in adults has a poor prognosis, and late recovery of consciousness is unlikely. Functional recovery is usually extremely poor. However, a few nontraumatic comatose patients have shown late recovery of both awareness and function. METHODS: A retrospective survey was conducted by reviewing the medical records of all inpatients to our department during the 1990s. Patients with persistent but reversible nontraumatic coma were identified according to the following criteria: (a) deep coma with a Glasgow Coma Scale (GCS) score of 7 or less on admission; (b) nontraumatic cause; (c) persistence of unconsciousness for longer than 1 month; and (d) subsequent recovery of GCS (total) to normal. The clinical spectrum of patients meeting these criteria was evaluated. RESULTS: Six patients (ages 16-75 years) met the criteria. Viral encephalitis was diagnosed in five (two with herpes simplex virus, two with cytomegalovirus, and one with Epstein-Barr virus or cytomegalovirus). Two young female patients with encephalitis manifested extremely protracted coma persisting for 3 and 18 months, respectively. Complications included nonconvulsive status epilepticus in two patients and relative overdose of clonazepam in one patient. CONCLUSION: Recognition of the clinical spectrum of persistent but reversible nontraumatic coma is important.