Decreased white matter integrity in neuropsychologically defined mild cognitive impairment is independent of cortical thinning.

Improved understanding of the pattern of white matter changes in early and prodromal Alzheimer's disease (AD) states such as mild cognitive impairment (MCI) is necessary to support earlier preclinical detection of AD, and debate remains whether white matter changes in MCI are secondary to gray matter changes. We applied neuropsychologically based MCI criteria to a sample of normally aging older adults; 32 participants met criteria for MCI and 81 participants were classified as normal control (NC) subjects. Whole-head high resolution T1 and diffusion tensor imaging scans were completed. Tract-Based Spatial Statistics was applied and a priori selected regions of interest were extracted. Hippocampal volume and cortical thickness averaged across regions with known vulnerability to AD were derived. Controlling for corticalthic kness, the MCI group showed decreased average fractional anisotropy (FA) and decreased FA in parietal white matter and in white matter underlying the entorhinal and posterior cingulate cortices relative to the NC group. Statistically controlling for cortical thickness, medial temporal FA was related to memory and parietal FA was related to executive functioning. These results provide further support for the potential role of white matter integrity as an early biomarker for individuals at risk for AD and highlight that changes in white matter may be independent of gray matter changes.

Double jeopardy! The additive consequences of negative affect on performance-monitoring decrements following traumatic brain injury.

Survivors of severe traumatic brain injury (TBI) are at increased risk for emotional sequelae. The current study utilized the error-related negativity (ERN) and posterror positivity (Pe) components of the event-related potential (ERP) to test the hypothesis that negative affect disproportionately impairs performance-monitoring following severe TBI. High-density ERPs were acquired while 20 survivors of severe TBI and 20 demographically matched controls performed a single-trial Stroop task. Response-locked ERPs were separately averaged for correct and error trials. Negative affect was measured as the single latent factor of measures of depression and anxiety. Groups did not differ on overall level of negative affect. Control and TBI participants did not differ on error rates as a function of negative affect, but differed in response times. ERP results revealed disproportionately smaller ERN amplitudes in participants with TBI relative to controls as a function of negative affect. Pe amplitude did not differ between groups. Negative affect inversely correlated with ERN amplitude in TBI but not control participants. Overall, results support a "double jeopardy" hypothesis of disproportionate impairments in performance monitoring when negative affect is overlaid on severe TBI.

Awareness of expressivity deficits in non-demented Parkinson disease.

A masked facial expression, one of the hallmark features of Parkinson disease (PD), can form the basis for misattributions by others about a patient's mood or interest levels. Reports of preserved intensity of internal emotional experience in PD participants raise the question of whether patients are aware of their outward expressivity levels. The aim of the present study was to determine whether PD participants exhibit deficits in overall emotional expressivity, and if so, whether they are aware of these deficits. We evaluated 37 non-demented PD participants and 21 comparison participants using the Berkeley Expressivity Questionnaire (BEQ). To examine awareness of emotional expressivity, we compared participant self-ratings of their own expressivity to ratings made by family members or close friends. Participants also completed questionnaires regarding depression and apathy and underwent motor examination and cognitive screening. PD participants' self-ratings of emotional expressivity were significantly lower than comparison participants' self-ratings. Even so, the PD participants viewed themselves as experiencing equivalent levels of emotional intensity to comparison participants, based on analysis of the BEQ subscales. Informant and PD participant self-ratings did not differ, indicating that PD participants accurately appraise the extent of their reduced expressivity. These findings suggest that anosognosia for emotional expressivity is not a prominent feature of nondemented Parkinson disease. Importantly, PD participants are aware of their reduced expressivity and report experiencing emotions as intensely as comparison participants. These findings highlight the view that diminished emotional expressivity in PD should not be mistaken for decreased subjective emotional experience.

Neuropsychological profile of a Filipino gentleman with X-linked dystonia-parkinsonism: a case report of Lubag disease.

X-Linked Dystonia-Parkinsonism (XDP or "Lubag") is a progressive neurodegenerative disorder unique to the Island of Panay in the Philippines. Imaging and autopsy studies have suggested involvement of the caudate and putamen in late stages. Because the clinical presentation of patients with XDP resembles that of patients with Parkinson disease or dystonia, it is reasonable to predict the neuropsychological profile might be similar; however, the neuropsychological profile of a XDP patient has not previously been published. We present the neuropsychological findings of a 67-year-old gentleman with a 10-year history of XDP who presented with parkinsonian and dystonic symptoms. He was evaluated for suitability for deep brain stimulation surgery. Neuropsychological findings demonstrated diffuse impairment involving memory, visuospatial, language, and executive functioning.