Gregory Swanwick

Behaviour disturbance and other predictors of carer burden in Alzheimer's disease.

Objective. To investigate predictors of carer burden in Alzheimers disease (AD).

Memory-related EEG power and coherence reductions in mild Alzheimer's disease.

OBJECTIVES To examine memory-related EEG power and coherence over temporal and central recording sites in patients with early Alzheimers disease (AD) and normal controls. METHOD EEG was recorded from central (Fz, Cz and Pz) and temporal (T3 and T4) electrodes while ten very mild AD patients and ten controls performed a Sternberg-type memory scanning task with three levels of working memory load. Spectral power in delta (0-3 Hz), theta (3-5 Hz), lower alpha1 (5-7 Hz), lower alpha2 (7-9 Hz), upper alpha (9-11 Hz) and beta (15-30 Hz) was averaged for temporal and central electrodes. Coherence was averaged between central electrodes, between central and right temporal electrodes and between central and left temporal electrodes. RESULTS While behavioral performance of very mild AD patients did not differ significantly from that of normal controls, findings suggest that normal controls but not AD patients respond to memory demands by increasing upper alpha power over temporal cortex. When compared with normal controls, AD patients had reduced upper alpha coherence between central and right temporal cortex. DISCUSSION Results are consistent with previous research on the role of upper alpha in semantic memory and suggest that very mild AD may inhibit selective synchronization of upper alpha in temporal lobes. Reduced coherence between central and temporal cortex is discussed in light of a neurological model of AD that hypothesizes reduced electrocortical efficiency and a breakdown of neural network communication to temporal lobes possibly resulting from temporal lobe atrophy.

Use of the Clock Drawing Task in the Diagnosis of Mild and Very Mild Alzheimer's Disease

The purpose of this study was to examine the utility of the clock drawing task (CDT) in differentiating between patients with mild and very mild Alzheimers disease (AD) and normal controls. Thirty normal elderly individuals and 30 patients with probable AD were entered into the study and asked, in a standard fashion, to draw a clock from memory. All the clocks were scored according to two previously described standardized scoring systems, and the accuracy of classification into normal or AD groups was determined. Both CDT scales could discriminate between moderate AD and normal aging but lacked sensitivity in the very mild AD cases; mild cases showed intermediate sensitivity. In conclusion, the CDT as a test for AD is insensitive in the early-stage cases, but sensitivity improves with increasing severity of dementia. The CDT is unlikely to be useful in distinguishing between AD in its early stages and normal aging.

Clinical application of electrophysiological markers in the differential diagnosis of depression and very mild Alzheimer's disease.

BACKGROUND--Current evidence indicates that, on their own, neither flash visual evoked responses (FVEPs) nor event related potentials (ERPs) are sufficiently useful to the clinician in the very early stages of memory dysfunction. However, the possibilities for the combined use of these measures has not been fully explored. METHODS--This study examined the clinical utility of combined FVEP and ERP-P300 component latencies as predictive markers in 16 patients with Alzheimers disease, 15 patients with depression, and 21 control subjects. RESULTS--There were significant group differences in FVEP P2 latency (P = 0.004) between the controls and both the depressive patients and those with very mild Alzheimers disease. There were no statistically significant group differences for the ERP component (N2/P300) amplitudes or latencies. The P300 component latency was positively correlated with both the FVEP N2 and FVEP P2 component latencies in the patients with Alzheimers disease but not in the control subjects or the depressed patients. A discriminant function, using two ERP and two FVEP component measures, gave an overall correct classification rate for dementia of 78%. In this study of very mildly impaired patients the FVEP latencies provided a more sensitive marker for the presence of cognitive dysfunction than P300 latency delay. CONCLUSIONS--The findings support the use of multimodal evoked potentials in the differential diagnosis of very mild Alzheimers disease and normal aging.

Prevalence of mental illness in an elderly community dwelling population using AGECAT

Objective: The purpose of this study was to determine the prevalence of a range of mental disorders in an elderly community dwelling population in Dublin using AGECAT, a reliable and standardised computerised diagnostic system that has been previously validated in community epidemiological surveys. Methods: A total of 451 individuals over the age of 65 in a GP group practice were interviewed using AGECAT. Results: Approximately one in five subjects had a mental illness according to AGECAT criteria. The prevalence of depression was 13.1% and did not change appreciably with age. 5.5% of subjects met organic ‘case’ criteria, and the frequency of organic cases increased with age, approximating 15% in the over 80 year age group. Neurotic disorders occurred with very low frequency, representing 1.1% of the subjects tested. Conclusions: These findings have implications for mentalhealth services planning at a local level, and underscore the utility of AGECAT as a tool for comparative crosscultural epidemiological surveys.

Letter and Category Fluency in Alzheimer's Disease: A Prognostic Indicator of Progression?

This study investigated differential patterns of performance by 40 Alzheimers disease (AD) patients on standardised letter and category fluency tests. The performance of 24 age and education matched controls was used to classify patients as relatively more letter fluency impaired (L < C, n = 15) or more category fluency impaired (C < L, n = 25), and clinical features distinguishing these patient subgroups were investigated. Category performance was equally impaired in both patient subgroups, whereas the L < C subgroups were particularly impaired on letter fluency. The subgroups differed significantly in duration of illness (24 months for L < C group, 47 months for C < L group; t = 2.69, p = 0.01) but did not differ in global dementia severity, age, education, general language ability, or functional status. Data on annual rate of change (ARC) on the Mini-Mental State Examination were available for 26 patients. While not statistically significant, subgroup ARC differences were suggestive of more rapid decline in the L < C patients, consistent with the finding of shorter duration of illness in this group. Word fluency tests may have potential as early predictors of rate of progression in AD.

Distinguishing between Patients with Depression or Very Mild Alzheimer's Disease Using the Delayed-Word-Recall Test

The present study investigated the accuracy of an extended version of the Delayed Word Recall (DWR) test in distinguishing patients with very mild Alzheimers disease (AD) (Mini Mental State Examination score > or = 23) from community-dwelling depressed/dysthymic patients. The DWR test was administered to 26 non-depressed patients who, at the time of DWR administration or on follow-up, fulfilled NINCDS/ADRDA criteria for probable AD, and to 20 age-matched non-dementing patients with a diagnosis of major depression (n = 12) or dysthymia (n = 8) according to DSM-III-R criteria. Sensitivity and specificity were, respectively, 96 and 100% for DWR free recall, and 92 and 100% for DWR recognition. In this study both DWR free recall and recognition measures were highly sensitive and specific in distinguishing very-mild-AD patients from depressed/dysthymic patients. The investigation of more severely depressed patients is warranted.

Assessment of progression and prognosis in ‘possible’ and ‘probable’ Alzheimer's disease

Objective. The objective of this study was to assess the rate of progression and clinical predictors of decline in subjects with ‘possible’ and ‘probable’ Alzheimers disease (AD).

Is Female Gender a Risk Factor for Alzheimer's Disease?

Despite a growing list of potential new risk factors for Alzheimer’s disease (AD), one of the oldest remains controversial. Is female gender a risk factor for AD? It is likely that the greatest influence on the gender differential in crude prevalence rates is the increasing incidence of dementia with age (Paykel et al., 1994) combined with the greater longevity of women (Moritz & Ostfeld, 1990). This must be distinguished from the hypothesis that there may also be a gender difference in the age-specific prevalence rates of some dementias such as AD. In turn, this could be due to either a higher incidence of dementia in women, or to longer survival times in women followingdiagnosis. What is the evidence for these hypotheses? First, with regard to age-specific prevalence rates, Jorm and colleagues (1987) analyzed 22 dementia prevalence studies carried out between 1945 and 1985. They reported that the overall age-adjusted prevalence of dementia showed no gender difference. When their analysis was adjusted for the specific dementia diagnosis, they found higher rates of AD for women but no difference for multi-infarct dementia. They pointed out that the 22 studies varied widely and that they did not all give age-specific prevalence data, with only 3 studies providing age-specific data for the gender/ diagnosis analysis. Hofman and colleagues (1991) analyzed ageand gender-specific prevalence rates from European studies carried out between 1980 and 1990. They reported a slightly higher rate of dementia in men for subjects under 75 years and a higher prevalence of dementia in women in the 75 years or older age group. More recently, Skoog and colleagues (1993) and Kirby and coworkers (1997) reported no significant gender difference in prevalence rates for AD or ”organic disorders,” respectively. However, three recent studies have reported higher rates in women. In a Chinese community sample, Zhang and colleagues (1990) found a higher age-specific prevalence rate in women for dementia as defined by a cutoff on the Mini-Mental State Examination. Consistent with the analysis of Hofman and coworkers (1991), the Framingham study (Bachman et al., 1992) found a higher age-specific prevalence of both dementia and AD in women compared to men in the 75 years or older age group, whereas Saunders and colleagues (1993) reported higher rates of ”organic disorder” in women for those over 75 years of age but no significant gender difference in younger age groups.

Initiating and monitoring cholinesterase inhibitor treatment for Alzheimer's disease

The availability of acetylcholinesterase inhibitors for the treatment of Alzheimers disease raises a number of clinical and ethical questions. Many of the guidelines published in an attempt to tackle these questions lack either clinical or scientific validity. Against this background a model is proposed whereby specialist monitoring using formal tests is neither appropriate nor necessary to determine whether an individual patient should continue or stop treatment. Instead the primary care physician should refer potentially suitable patients for specialist assessment to confirm the diagnosis/ He/she should then initiate, monitor, and discontinue treatment based on the establishment of realistic treatment goals agreed with the patient/carer at the outset. Copyright