The validity of informant report for grading the severity of Alzheimer's dementia.

The validity of informant-based techniques has been established for the detection of dementia cases by non-pathological individuals, but is still controversial for the assessment of the severity of dementia. This study aimed at ascertaining whether informant-based evaluation (the so-called informant report) of the cognitive and behavioral impairment of a patient is valid for grading the severity of dementia, and consistent with objective assessment of the patient's cognitive and behavioral functioning. We enrolled 96 community-dwelling outpatients and 56 controls assessed at the Geriatric Evaluation Unit of the University of Modena, Italy. All patients scored lower than 27 on the MMSE, and met DSM-IV inclusion criteria for Alzheimer's dementia. Patients and controls were administered the CAMDEX interview, containing a section which collects participant (patient or control) and informant evaluations on dementia-related cognitive and behavioral deficits. The informant report resulted effective at MANOVA for grading the severity of dementia in 4 of its 5 measures (namely, memory, everyday activities, general mental functioning and depressed mood), and was correlated with the scores of several scales of the CAMDEX cognitive section (i.e., CAMCOG). Instead, the participant's (patient or control) report showed a lower capacity for grading dementia, and was poorly correlated with the psychometric outcomes of cognitive functioning. On the whole, the results corroborated the validity of the informant report in the diagnostic work-up for grading dementia, given its sensitivity to the severity of dementia, and its consistency with cognitive psychometric outcomes.

Shifting attention between objects.

Experiment 1 used a modified spatial cueing paradigm that was introduced by Egly et al. [J. Exp. Psychol. Gen. 123 (1994) 161] to investigate the cost incurred in shifting attention within an object as opposed to shifting attention between objects. Subjects were presented with two outline rectangles and had to detect a target (a luminance increment) that could appear in the cued location (valid trials), in an uncued location inside the cued rectangle (inside-invalid trials), or in an uncued location inside the uncued rectangle (outside-invalid trials). Valid trials were faster than invalid trials, and inside-invalid trials were faster than outside-invalid trials. In Experiment 2, the two rectangles were joined to form a unitary object. Here, no difference was found between outside-invalid trials and inside-invalid trials. Experiment 3 showed that the delayed response on outside-invalid trials in Experiment 1 was not due to attention needing to cross the figural borders in order to re-orient to the uncued rectangle. The results were interpreted as showing that an extra cost is incurred for shifting attention between different objects.

Response strategies and the Simon effect.

The study investigated whether the Simon effect, and its facilitation and interference components, shows up in reaction time (RT) or in movement time (MT), depending on the response strategy. Experiment 1 replicated a study by Hietanen and Rämä. Subjects had to press one of two lateralised keys in response to one of two stimuli. The stimuli were presented in the center (neutral condition) or to the left or right side (corresponding or non-corresponding conditions). To press the response key, a reaching movement was necessary, and both RT and MT were recorded. One group of subjects showed an RT facilitation effect and an MT interference effect. Another group of subjects showed both MT facilitation and MT interference effects. It was hypothesized that the two groups used different response strategies. In Exps. 2 and 3, the subjects were explicitly instructed to use the two strategies that were hypothesized for Exp. 1. The results showed that whether facilitation and interference manifest themselves in RT or MT depends on the response strategy adopted by the subjects.

Age-related slowing of control processes: evidence from a response coordination task.

Normal aging is associated with slowing of performance mostly due to a slowed functioning of central response-related processes. In this paper we set out to discover whether slowing occurs also when the process controlling the coordination of responses is engaged by the task. To this end, we compared the mean-reaction time performance of two groups of subjects (young vs. elderly) in single- and dual-task experimental paradigm. The response coordination process is required only by the dual-task paradigm. The results indicate that, in the dual-task situation, the elderly are markedly slower than young subjects. The eventual relevance of information-processing speed in determining the cognitive performance of the elderly is considered in the discussion of the results.

Facilitation and interference components in the Simon effect.

In four experiments we investigated whether the Simon effect consists of both facilitation and interference. In Experiment 1 subjects had to press one of two lateralized keys in response to one of two stimuli (a rectangle or a square). The stimuli were presented at fixation or to the right or left of it. The stimulus-response mappings could be corresponding (i.e., right key--rectangle or square on the right side), non-corresponding (i.e., right key--rectangle or square on the left side), or neutral (i.e., stimulus in the center). Results showed both facilitation and interference effects, but interference was three times greater than facilitation. To test whether the neutral position was favored by visual acuity, Experiments 2, 3 and 4 used slight different displays where visual acuity was the same at every stimulus position. Results indicated that the Simon effect is comprised of facilitation and interference components of the same magnitude. These findings were discussed with reference to dual-route models of the Simon effect.

Validation of the full and short forms of the CAMDEX interview for diagnosing dementia: evidence from a one-year follow-up study.

The sensitivity and specificity of the two forms of the CAMDEX interview for dementia diagnosis were assessed in a 1-year follow-up study. At the beginning of the study, 60 patients (22 males and 38 females) who met DSM-IV criteria for dementia and 60 matched controls (15 males and 45 females), were administered the short form of the CAMDEX (short CAMDEX) 3 months after the full one (full CAMDEX). At the follow-up, all patients were administered both the full and short CAMDEX (again with a 3-month interval), whereas controls were administered either CAMDEX form (in any case, at a 12-month interval from initial testing). Upon initial testing, the sensitivity of the full CAMCOG proved to be significantly higher than that of the short CAMCOG, while the opposite trend was observed for specificity, that is the sensitivity of the full Organicity was lower than that of the short Organicity, with specificity remaining equal in the two forms. Upon follow-up, the specificity and sensitivity levels of the two forms did not significantly differ for the CAMCOG and Organicity indices. Moreover, in detecting mildly demented patients, the full CAMCOG proved to be more accurate than the short one, while the opposite trend was observed for Organicity. Among the dementia subjects, significant correlations were found between the homologous indices of the two forms for both test sessions. On the whole, the short CAMDEX appears to maintain most of the psychometric properties of the full version and therefore the two CAMDEX forms can be considered to be interchangeable.

The validity of informant reports in assessing the severity of dementia: evidence from the CAMDEX interview.

The evaluation of a patient's mental state, overall clinical profile and behavioural disturbance in the process of diagnosing dementia requires at least two sources of information: the patient and the informant. Since the severity of the dementia may interfere with the subjective perception of these disorders, it is important to evaluate the consistency between these two sources of information and the clinical and psychometric evaluation made by the physician. Accordingly, in this study five behavioural areas, derived from the semi-structured interview schedule provided by the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX, i.e., Sleep, Depressed Mood, Everyday Activity, Memory and Global Mental Functioning) have been tested on the patient and his/her informant. Eighty dementia patients (mean age = 74 years) and their informants participated in the study. The dementia group was subdivided into two levels of severity according to DSM-IIIR criteria: 41 with mild dementia and 39 with moderate dementia, respectively, matched for age and schooling. The rating of impairment was found to increase along with the severity of dementia in all the above-mentioned areas, except for sleep. However, the source of information per se significantly influenced the evaluation of memory functioning. Moreover, the significant interaction between the two factors considered indicates that memory functioning is evaluated quite differently by the patients and the informants, as only in the assessment made by the latter group did the impairment increase in parallel with severity of dementia. Finally, whereas none of the subjective measures recorded in the patients were significantly correlated with their test scores, the correlations between the informant memory appraisals and patient test results proved to be significant. The present findings confirm the validity of informant reports in assessing cognitive and memory disorders in early-stage dementia, as well as in distinguishing patients with mild from those with moderate dementia.

The Simon effect occurs relative to the direction of an attention shift.

We investigated whether the Simon effect depends on the orienting of attention. In Experiment 1, participants were required to execute left-right discriminative responses to 2 patterns that were presented to the left or right of fixation. The 2 patterns were similar, and the discrimination was difficult. A letter at fixation signaled whether the current trial was a catch trial. The results showed a reversal of the Simon effect. That is, spatially noncorresponding responses were faster than spatially corresponding responses. In Experiment 2, the discrimination of the relevant stimulus attribute was easy. In Experiment 3, the discrimination of the relevant stimulus attribute was difficult, but the stimulus exposure time was long. In either experiment, the regular Simon effect was reinstated. In Experiment 4, the letter that signaled a catch trial appeared to the left or right of the imperative stimulus. The Simon effect occurred relative to the position of the letter.

The influence of depression on memory and metamemory in the elderly.

This study aimed to assess the relationships among depression level, memory and metamemory scores on a large sample of elderly subjects (139 men and 147 women). Preliminary examination showed that none of the sampled subjects had intellectual impairment (as assessed by means of the Mini-Mental State Examination) or neuropsychiatric symptoms. Each subject was administered the Randt Memory Test (RMT), the Sehulster Memory Scale (SMS) and the Geriatric Depression Scale (GDS). A Multivariate Analysis of Covariance revealed a negative influence of depression on the two RMT measures (Acquisition-Recall: AR; Delayed Memory: DM) and on the three SMS measures (Set1: self-comparison; Set2: memory complaints; Set3: peer comparison), and of age on AR and DM, and Set1 and Set2. A Multivariate Regression Analysis showed that DM scores were positively correlated with Set2 in men and women, and with Set1 in women and Set3 in men, whereas AR scores related to Set2 and Set3 in men and Set1 in women. In addition, depression influenced negatively Set1, Set2 and AR scores in both men and women and DM scores only in men. On the whole, the results suggest that depression, memory and metamemory are rather closely related in non-severely depressed older individuals, albeit with slightly different patterns in men and women, and that some areas of metamemory are congruent with objective functioning regardless of the level of depressive symptoms.

Transient global amnesia: memory and metamemory.

Twenty patients (mean age 64 years) with a previous episode of transient global amnesia (TGA) were examined to assess the functioning of objective memory (by using the Randt Memory Test), the metamemory capacities (Sehulster Memory Scale), the residual level of retrograde amnesia (Questionnaire of Remote Events), and the level of depression (Geriatric Depression Scale). Patients with residual retrograde amnesia scored significantly lower than non-amnesic ones on indices of both short-term and long-term memory, and for one of three main metamemory components, namely self-rating of memory functioning through comparison with memory functioning of peers (Set3). Age, time interval from TGA attack and TGA duration did not prove to influence memory and metamemory scores. Retrograde amnesia and depression were rather substantially associated (1/5), and this association was found to negatively influence nearly all memory and metamemory scores. Depression level showed a positive correlation with short-term memory functioning in non-amnesics. The different pattern and strength of the relationships between metamemory components and objective memory dimensions observed in amnesics and non-amnesics indicate that metamemory evaluations are more closely related to memory functioning in amnesics than in non-amnesics.

Validation of the full and short forms of the CAMDEX interview for diagnosing dementia. Cambridge Examination for Mental Disorders of the Elderly.

The present study compares the sensitivity and specificity of the short and full forms of the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX) interview in diagnosing dementia. We tested 73 subjects meeting DSM-IIIR criteria for dementia and 61 matched controls. The short version was applied 3 months after the full one to guarantee a relative stability of the tested functions. Referred to an independent clinical rating made at the beginning of the study, the levels of sensitivity and specificity were not significantly different in the two forms and fully comparable with those of the original full English version. Moreover, the scores on analogous sections of the two versions were highly correlated in the demented and control groups. These findings support the hypothesis that the short form of the CAMDEX maintains the psychometric properties of the full one, and consequently can be used in diagnostic routines for a variety of clinical and research purposes.