Bayard Miller

Relative frequencies of Alzheimer disease, Lewy body, vascular and frontotemporal dementia, and hippocampal sclerosis in the State of Florida Brain Bank

Alzheimer disease (AD) is the most common dementing illness in the elderly, but there is equivocal evidence regarding the frequency of other disorders such as Lewy body disease (LBD), vascular dementia (VaD), frontotemporal dementia (FTD), and hippocampal sclerosis (HS). This ambiguity may be related to factors such as the age and gender of subjects with dementia. Therefore, the objective of this study was to calculate the relative frequencies of AD, LBD, VaD, FTD, and HS among 382 subjects with dementia from the State of Florida Brain Bank and to study the effect of age and gender on these frequencies. AD was the most frequent pathologic finding (77%), followed by LBD (26%), VaD (18%), HS (13%), and FTD (5%). Mixed pathology was common: Concomitant AD was present in 66% of LBD patients, 77% of VaD patients, and 66% of HS patients. The relative frequency of VaD increased with age, whereas the relative frequencies of FTD and LBD declined with age. Males were overrepresented among those with LBD, whereas females were overrepresented among AD subjects with onset age over 70 years. These estimates of the a priori probabilities of dementing disorders have implications for clinicians and researchers.

Neglect after mesencephalic reticular formation lesions

Discrete unilateral mesencephalic reticular formation lesions were made in four female stump-tailed macacques (Macaca speciosa). Control lesions of identical size were placed in the left medial dorsal thalamic nucleus, left ventral posterolateral thalamic nucleus, and left pontine nucleus. Experimental subjects showed profound tactile, visual and auditory neglect, in addition to ipsilateral hemispheric slowing on EEG. Controls did not demonstrate either phenomenon. This study suggests that neglect results from any lesion along the corticolimbic-reticular activating loop, and that the basis of neglect is a unilateral defect in the alerting response to sensory stimuli because of a disruption of this loop.

Virtual multi-tools for hand and tool-based interaction with life-size virtual human agents

A common approach when simulating face-to-face interpersonal scenarios with virtual humans is to afford users only verbal interaction while providing rich verbal and non-verbal interaction from the virtual human. This is due to the difficulty in providing robust recognition of user non-verbal behavior and interpretation of these behaviors within the context of the verbal interaction between user and virtual human. To afford robust hand and tool-based non-verbal interaction with life-sized virtual humans, we propose virtual multi-tools. A single hand-held, tracked interaction device acts as a surrogate for the virtual multi-tools: the users hand, multiple tools, and other objects. By combining six degree-of-freedom, high update rate tracking with extra degrees of freedom provided by buttons and triggers, a commodity device, the Nintendo Wii Remote, provides the kinesthetic and haptic feedback necessary to provide a high-fidelity estimation of the natural, unencumbered interaction provided by ones hands and physical hand-held tools. These qualities allow virtual multi-tools to be a less error-prone interface to social and task-oriented non-verbal interaction with a life-sized virtual human. This paper discusses the implementation of virtual multi-tools for hand and tool-based interaction with life-sized virtual humans, and provides an initial evaluation of the usability of virtual multi-tools in the medical education scenario of conducting a neurological exam of a virtual human.

A memory defect in uremic encephalopathy

It has been demonstrated that anesthesia primarily affects the reticular activating system and psychological studies on patients undergoing anesthesia demonstrated a verbal memory defect. This study was performed in order to determine whether metabolic (uremic) encephalopathy follows the Jacksonian dissolution hypothesis and disrupts cortical function or whether it acts like an anesthetic, causes dysfunction in phylogenetically older systems and thereby produces a memory defect. Twenty-four uremic subjects were tested for memory function, language function, and intellectual function, and compared to 12 control subjects. The greatest difference between the groups was in immediate memory function suggesting that uremia probably acts in a manner similar to anesthesia (by causing dysfunction in the reticular activating system). It is postulated that poor arousal interferes with rehearsal and rehearsal is probably an important component of immediate memory.

TBI surveillance using the common data elements for traumatic brain injury: a population study

BackgroundTo characterize the patterns of presentation of adults with head injury to the Emergency Department.MethodsThis is a cohort study that sought to collect injury and outcome variables with the goal of characterizing the very early natural history of traumatic brain injury in adults. This IRB-approved project was conducted in collaboration with our Institution’s Center for Translational Science Institute. Data were entered in REDCap, a secure database. Statistical analyses were performed using JMP 10.0 pro for Windows.ResultsThe cohort consisted of 2,394 adults, with 40% being women and 79% Caucasian. The most common mechanism was fall (47%) followed by motor vehicle collision (MVC) (36%). Patients sustaining an MVC were significantly younger than those whose head injury was secondary to a fall (P < 0.0001). Ninety-one percent had CT imaging; hemorrhage was significantly more likely with worse severity as measured by the Glasgow Coma Score (chi-square, P < 0.0001). Forty-four percent were admitted to the hospital, with half requiring ICU admission. In-hospital death was observed in 5.4%, while neurosurgical intervention was required in 8%. For all outcomes, worse TBI severity per GCS was significantly associated with worse outcomes (logistic regression, P < 0.0001, adjusted for age).ConclusionThese cohort data highlight the burden of TBI in the Emergency Department and provide important demographic trends for further research.