Biomedical subjects

Daniel Bittner

Publications and source records attributed to Daniel Bittner.

4 recordsLinked to original sources

PubMed2005

Screening for cognitive impairment: a triage for outpatient care.

The current increase in aged individuals in number and proportion of the general population warrants dependable strategies to improve early detection of cognitive impairment. It was the goal of the present study to develop a triage for bedside testing and outpatient services. In a prospective clinical cohort study at the outpatient Memory Clinic, University of Ulm, Germany, 232 subjects were diagnosed with Alzheimer's disease [AD; NINCDS-ADRDA criteria; n = 66; age 65.9 +/- 7.3 years (mean +/- SD); Mini Mental State Examination (MMSE) score 23.4 +/- 4.1], mild cognitive impairment (MCI; criteria of Petersen et al.; n = 48; age 66.4 +/- 7.1 years; MMSE score 28.3 +/- 1.5), and major depressive disorder (DSM-IV criteria; n = 61; age 63.4 +/- 8.0 years; MMSE score 28.6 +/- 1.6). Diagnosis was secured with extensive neuropsychological, clinical, radiological, and laboratory investigations. Six brief screening tests including the Memory Impairment Screen (MIS), Letter Sorting Test (LST), Verbal Fluency (VF), and Clock Drawing Test (CDT) were assessed independently from the diagnostic procedure. We compared single items and composite scores. LST yielded a diagnostic accuracy of 0.81 and 0.62 for AD and MCI patients versus controls, respectively. With the MIS, diagnostic accuracy was 0.89 and 0.71, respectively. With a combination of LST, MIS, VF, and CDT, a sensitivity for AD and MCI patients of 1.00 and 0.83 was achieved. Thus, single-item screening (e.g. LST, VF) taking little more than 1 min and suitable for bedside testing or brief screening in the general practitioner's office yields diagnostic accuracy comparable to standard laboratory tests for other diseases. A composite of screening tests suitable for application in general outpatient care in neurological and psychiatric services reliably detects patients with AD and MCI.

Aged↗

PubMed2003

Screening for cognitive impairment in patients with acute stroke.

BACKGROUND: Formal assessment of cognitive impairment is rare in acute stroke, yet. It was the goal to utilize easy-to-apply established screening tests to assess cognitive impairment from any cause in patients with acute ischemic stroke. METHODS: 209 consecutive patients (69.8 +/- 13.3 years, mean +/- SD; 117 male, 92 female) admitted to an acute stroke unit, which serves as a community stroke center, and diagnosed as having acute cerebral ischemia from any cause were investigated within 24 h of stroke onset and in part followed up after 3 months. Orientation and aphasia were assessed with the ADAScog subscales orientation and aphasia, verbal memory with Buschke's Memory Impairment Screen, and concentration/working memory with a letter sorting test. RESULTS: On admission, 74.6% were impaired on the Memory Impairment Screen, 77.0% on the letter sorting test, 45.0 and 24.9% on the ADAScog subscales aphasia and orientation. Results of the Memory Impairment Screen and letter sorting test were similar at the follow-up after 3 months. CONCLUSION: Formal brief assessment of cognitive deficits with tests not requiring motor capabilities in unselected patients with an acute cerebral ischemic event reveals widespread deficits. This needs to be considered when obtaining informed consent from the patients and instructing them. Routine formalized screening may thus improve care for patients with acute stroke. Patients with impairment on admission should be followed up, diagnosed concerning preexisting or poststroke dementia with a more extensive workup and eventually treated.

Acute Disease↗

PubMed2002

Subjective memory complaints: objective neural markers in patients with Alzheimer's disease and major depressive disorder.

Patients with probable Alzheimer's disease and depressive patients frequently present with subjective memory complaints. Objective distinction of underlying neuronal substrate malfunction and early cross-sectional differential diagnosis have been elusive thus far. We used repetitive learning and free recall of abstract geometric patterns during functional magnetic resonance imaging to assess episodic memory in older subjects (ages 56-64 years) who sought first-time medical attention with subjective memory complaints and were diagnosed with probable Alzheimer's disease (NINCDS-ADRDA criteria; ages 51-67 years) or major depressive disorder (DSM-IV; ages 50-65 years). Contrasting healthy seniors or depressive patients with Alzheimer's disease patients revealed superiority of hippocampal activation. Contrasting Alzheimer's disease patients with seniors showed bilateral prefrontal activity as a correlate of futile compensation of episodic memory failure. Contrasting patients who had major depressive disorder with seniors or patients who had Alzheimer's disease showed bilateral activation of the orbitofrontal cortex and the anterior cingulate. Subjective memory complaints may be classified objectively and very early with functional magnetic resonance imaging of episodic memory in groups of patients with Alzheimer's disease and depressive syndrome. This may facilitate drug trials with evaluation of specific treatments, but further studies will be needed to establish the differential diagnosis for the individual patient.

Aged↗

PubMedDate not supplied

Variability in memory performance in aged healthy individuals: an fMRI study.

Episodic memory performance varies in older subjects but underlying biological correlates remain as yet ambiguous. We investigated episodic memory in healthy older individuals (n=24; mean age: 64.4+/-6.7 years) without subjective memory complaints or objective cognitive impairment. Episodic memory was assessed with repetitive learning and recall of abstract geometric patterns during fMRI. Group analysis of brain activity during initial learning and maximum recall revealed hippocampal activation. Correlation analysis of brain activation and task performance demonstrated significant hippocampal activity during initial learning and maximum recall in a success-dependent manner. Neither age nor gray matter densities correlated with hippocampal activation. Functional imaging of episodic memory thus permits to detect objectively variability in hippocampal recruitment in healthy aged individuals without subjective memory complaints. Correlation analysis of brain activation and performance during an episodic memory task may be used to determine and follow-up hippocampal malfunction in a very sensitive manner.

Aged↗