Faculty Bibliography

BACKGROUND: Subjective cognitive impairment (SCI) has been a common, but poorly understood condition, frequently occurring in older persons. METHODS: The past and the emerging literature on SCI and synonymously named conditions is reviewed. RESULTS: Findings include: (1) There is support from at least one longitudinal study for a long-standing concept of SCI as a pre-mild cognitive impairment (MCI) condition lasting approximately 15years. (2) There are complex relationships between SCI and depression and anxiety. (3) Differences in SCI subjects from age-matched non-SCI persons are being published in terms of cognitive tests, hippocampal gray matter density, hippocampal volumes, cerebral metabolism, and urinary cortisol levels. Psychometric and dementia test score differences between SCI and MCI subjects have long been evident. (4) Predictive electrophysiologic features of subsequent decline in SCI subjects are being published. CONCLUSIONS: Studies of therapeutic agents in SCI treatment and resultant Alzheimer's disease prevention appear to be feasible. These trials are also necessary from a public health perspective

Global measures used in treatment trials in dementia encompass two distinct categories: (1) clinician's interview-based global severity scales, and (2) clinician's interview-based global change scales. The global severity scales that have been used include: the Clinical Dementia Rating (CDR) and the related CDR-sum of boxes (CDR-SB), the Global Deterioration Scale (GDS), and the Functional Assessment Staging (FAST) procedure. The global severity scales are clearly useful in subject categorization in treatment trials, in part because they are relatively free of many of the sociocultural biases inherent in mental status and psychometric descriptors. Global severity scales can also be used to demonstrate therapeutic efficacy in terms of the general progression of the dementia process. These measures have also proven to be useful in sensitively assessing pharmacotherapeutic effects in Alzheimer's disease (AD) treatment trials. For example, in pivotal trials: (1) in Mild to Moderate AD, the GDS has shown significant change in response to medication, whereas the results on the Mini-mental State Examination (MMSE) were not significant, and (2) in Moderate to Severe AD, the FAST has shown significant pharmacotherapeutic efficacy, whereas the results using the MMSE were not significant. The global change scales employed in dementia trials differ widely in assessment methodology. Clinical Global Impressions of Change (CGIC) scales do not have defined methodologies, whereas Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus) scales are much more elaborate. The CIBIC-Plus procedures require an independent clinician assessment and can provide independent, comprehensive evidence of therapeutic efficacy. The CIBIC-Plus procedure may also be useful in sensitively assessing efficacy in future prevention trials, for example in subjects with Subjective Cognitive Impairment. For Mild Cognitive Impairment (MCI), global severity scales already appear to be one modality for the sensitive assessment of change. The CIBIC-Plus procedures might also productively be applied in future MCI therapeutic trials

Amyloid beta (Abeta) immunoreactivity in neurons was examined in brains of 32 control subjects, 31 people with Down syndrome, and 36 patients with sporadic Alzheimer's disease to determine if intraneuronal Abeta immunoreactivity is an early manifestation of Alzheimer-type pathology leading to fibrillar plaque formation and/or neurofibrillary degeneration. The appearance of Abeta immunoreactivity in neurons in infants and stable neuron-type specific Abeta immunoreactivity in a majority of brain structures during late childhood, adulthood, and normal aging does not support this hypothesis. The absence or detection of only traces of reaction with antibodies against 4-13 aa and 8-17 aa of Abeta in neurons indicated that intraneuronal Abeta was mainly a product of alpha- and gamma-secretases (Abeta(17-40/42)). The presence of N-terminally truncated Abeta(17-40) and Abeta(17-42) in the control brains was confirmed by Western blotting and the identity of Abeta(17-40) was confirmed by mass spectrometry. The prevalence of products of alpha- and gamma -secretases in neurons and beta- and gamma-secretases in plaques argues against major contribution of Abeta-immunopositive material detected in neuronal soma to amyloid deposit in plaques. The strongest intraneuronal Abeta(17-42) immunoreactivity was observed in structures with low susceptibility to fibrillar Abeta deposition, neurofibrillary degeneration, and neuronal loss compared to areas more vulnerable to Alzheimer-type pathology. These observations indicate that the intraneuronal Abeta immunoreactivity detected in this study is not a predictor of brain amyloidosis or neurofibrillary degeneration. The constant level of Abeta immunoreactivity in structures free from neuronal pathology during essentially the entire life span suggests that intraneuronal amino-terminally truncated Abeta represents a product of normal neuronal metabolism

Background/Aims: Subjective memory complaint (SMC) in normal individuals may predict future cognitive decline. The goal of this study was to examine whether the probability of decline increases with growing intensity of complaint. Methods: Normal subjects over the age of 50 years were included in a longitudinal retrospective study (mean follow-up time = 8 years). All subjects (n = 230) underwent cognitive and medical examination at baseline. The presence of SMC was determined based on Global Deterioration Scale staging. A subgroup of 83 participants also received baseline assessment for the intensity of SMC. Logistic regression was used to predict outcome from baseline variables. Three outcome groups were established at the final visit: nondeclining, declining and diagnostically unstable (i.e. the diagnosis changed over time: from normal to mild cognitive impairment, then back to normal). Results: The presence of SMC was a predictor of future decline but also increased the likelihood of the unstable diagnosis. Increasing intensity of SMC did not further raise the risk for decline. High intensity of complaints and more pronounced affective symptoms predicted the unstable clinical diagnosis. Conclusions: The presence of SMC contributes to the risk of future decline, however, the increasing intensity of the perceived impairment does not further enhance the risk.

BACKGROUND/AIMS: Previously we have shown that functional declines in Parkinson's disease (PD) and Alzheimer's disease (AD) correlate to global measures of cognitive decline. We now determine if the correlation between cognitive impairment and functional ability in PD is similar to that in AD using individual cognitive measures. METHODS: 93 PD subjects and 124 AD/MCI subjects underwent the Functional Assessment Staging (FAST), the Global Deterioration Scale (GDS), and a neuropsychological battery. RESULTS: In PD subjects, the FAST and GDS correlated significantly with Rey Auditory Verbal Learning Test (AVLT), Controlled Oral Word Association (COWA), Animal Fluency, and Stroop but not with Clock Draw or Judgment Line Orientation (JLO). In AD/MCI subjects, FAST and GDS correlated with all neuropsychological components except Stroop. In the AD/MCI group, the UPDRS significantly correlated with the FAST, GDS, MMSE, and all neuropsychological parameters except the Stroop. In the PD group, the motor UPDRS significantly correlated significantly with FAST, GDS, MMSE and all neuropsychological parameters except Digit Span, Stroop, Clock Draw and JLO. CONCLUSIONS: Similar to AD, functional decline in PD correlates with multiple measures of cognitive impairment. Some differences between PD and AD may be explained by the influence of motor disability and declines in visuospatial function in PD.

BACKGROUND: Because primary prevention trials will require large samples and modest treatment effects are expected, the use of standard clinician-administered, clinic-based measures are unlikely to be feasible. There is a need for proxy-administered outcome measures. The goal of the Alzheimer's Disease Cooperative Study (ADCS) Prevention Instrument Project was to conduct a simulated Alzheimer disease prevention trial in 650 nondemented elderly (Ferris et al, 2006). This involved comparison of data acquisition from both home and clinic and the use of both informant-ratings and self-ratings. Important outcomes included clinical global impressions of change (CGIC) as indicators of clinically meaningful change. Such ratings provide verification that the effects of a medication as measured on rating scales are readily observable and clinically meaningful. One objective was to develop self-rated and study partner-rated CGICs optimized for nondemented elderly or people with very early Alzheimer disease. An important consideration was whether global assessments are specific and sensitive measures of change during a prevention trial. METHODS: A self-administered CGIC and a study partner-rated CGIC were developed to be used either in the clinic or at home. Using 3-month follow-up data, we determined its reliability and validity with 317 subject-partner pairs. We compared subject-ratings with partner-ratings, clinic-based with home-based ratings, and ratings based on severity as determined by the Clinical Dementia Rating scale. RESULTS: There were no differences between clinic and home ratings. Overall, 24% of subjects rated themselves, and 10% of study partners rated the subjects, as minimally to markedly improved. Subjects and partners agreed to within 1 point of their ratings 83% of the time on the 7-point scale. There were weak correlations, generally <0.20, with change scores of selected clinical rating scales. DISCUSSION: The CGICs behaved as expected, showing no overall change over 3 months, no difference between administrations at home compared with clinics, and concurrent validity. Some subjects tended to rate themselves better than their partners rated them. These analyses show the potential for using home-based CGICs which can be completed with minimal supervision and allow assessments of potential preventative interventions

Planning is being initiated for the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders 5th ed. (DSM-V). Therefore, the dementia diagnosis criteria in the American Psychiatric Association's DSM-IV-TR (4th ed, text revision, 2000) have been compared with the World Health Organization's International Classification of Diseases (10th revision, 1992). Critiques are based primarily on (a) internal consistency and validity of the classification, (b) historical development of the field, (c) conclusions of consensus conferences, and (d) current knowledge and practice. It is suggested that (1) the entire category be labeled 'cognitive disorders,' to better characterize this group of disorders, (2) there is no longer any scientific basis for the presenile versus senile dementia dichotomy at age 65, (3) Alzheimer's disease no longer should have unique status as a 'diagnosis of exclusion,' (4) future manuals should incorporate knowledge regarding the clinical manifestation and course of Alzheimer's disease and other dementias, and (5) the classification 'Pick's disease' should be broadened to 'frontotemporal dementias.' DSM-V should incorporate continuing advances in the neuroscience knowledge base and understanding of these disorders