• Alzheimer's disease;
  • behavioral disturbance;
  • cognition;
  • neuropsychiatry;
  • psychosis


  1. Top of page
  2. Abstract
  6. Conflicts of interest declaration
  7. Description of authors' roles

Aim:  Alzheimer's disease (AD) is characterized by cognitive symptoms and behavioral symptoms, and their association is inconsistent. The aim of this study was to investigate the relationship between cognitive function and the changes in behavioral and psychological symptoms of dementia (BPSD) in patients with AD.

Methods:  A total of 101 patients with probable AD were enrolled (57 women and 44 men, mean age 77.6 ± 7.7 years). The Category Verbal Fluency Test (CVFT), the Mini-Mental State Examination (MMSE), the Constructional Praxis Test, the Delayed Word Recall Test, the Clinical Dementia Rating Scale, and the Neuropsychiatry Inventory (NPI) were administered at baseline. The NPI was reassessed with a median follow-up duration of 10 months (range 6–18 months). The change in the NPI scores was defined as the end-point score of the NPI minus the initial one. The associations between the changes in NPI total score, its four subdomains (hyperactivity, psychosis, affection, and apathy), and cognitive function were examined using multivariate linear models. The results were adjusted for confounders including demographics, baseline NPI, and duration of follow up.

Results:  The mean MMSE was 18.6 ± 5.6, the CVFT score was 7.1 ± 3.9, and the NPI score was 10.9 ± 13.8. Regression analyses found that the CVFT score (β = −0.32, P = 0.004) was significantly associated with the change in NPI score, but not the MMSE, the Delayed Word Recall score, or the Constructional Praxis score. The CVFT score was significantly associated with changes in the psychosis subdomain (β = −0.34, P = 0.001), but not the other subdomains.

Conclusions:  Our study showed that CVFT was predictive of the changes in behavior disturbance in patients with AD, particularly in the psychosis domain.

ALZHEIMER'S DISEASE (AD) is characterized by impairment in memory, visuospatial functions, language, executive function, and neuropsychiatric symptoms.1 Behavioural and psychological symptoms of dementia (BPSD)2 are being increasingly recognized as an important aspect of dementia because of the impacts on both patients and their caregivers, premature institutionalization, and increased costs of care.3–5

Several studies have been conducted to determine the predictive factors of behavioral disturbances in patients with AD. Baseline behavioral disturbance, baseline stage of dementia, use of support services, early age of onset, extrapyramidal symptoms, and apolipoprotein e4 allele have been reported to be associated with BPSD among patients with AD.6,7 It is also evident that there is a link between cognitive impairment and behavioral symptoms in patients with AD.8 In recent years, cross-sectional studies suggest that executive dysfunction in dementia is associated with both functional limitation and disturbed behavior.9–11 One current cohort study has reported that early executive function impairment is a predictor of behavior disturbance at a later time in demented patients indicated by comprehensive neuropsychological battery, including category verbal fluency, similarities, ideational fluency and visual reasoning.12 Understanding the changes in BPSD would be helpful in clinical practice and caregivers' counseling,13 however, follow-up studies of BPSD are relatively scarce.

A brief and easy-to-perform neuropsychological measure is more practical to use on the patient first showing in the outpatient clinic setting. The Category Verbal Fluency Test (CVFT), a simple instrument for cognitive function evaluation, has been used to assess semantic memory, executive function and language.14,15 CVFT is considered as an appropriate screening tool for AD, questionable dementia and mild cognitive impairment.16,17 It has been shown to associate with functional decline,18 to differentiate between dementia subtypes,19 and to predict mortality in patients with AD.20 The performance of CVFT in dementia is associated with both functional impairment and disturbed behavior in cross-sectional studies.21

The aim of this study was to examine the patients with diagnosis of AD in a memory outpatient clinic setting to determine whether baseline Mini-Mental State Examination (MMSE) or CVFT was related to the changes in behavioral disturbances at a follow-up study.


  1. Top of page
  2. Abstract
  6. Conflicts of interest declaration
  7. Description of authors' roles


Chinese patients living with family caregivers with a diagnosis of AD were recruited from the memory outpatient clinics of Taipei Veterans' General Hospital, which is a medical center in Taiwan, from August 2004 to July 2008. All of the patients met the DSM-IV criteria22 for dementia of the Alzheimer type and the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association criteria for probable AD.23 All subjects gave informed consent according to our institutional guidelines and the recommendations of the Declaration of Helsinki. When a patient was not able to understand the consent conditions, the patient's responsible family member gave consent. The study was approved by the institutional review board of Taipei Veterans' General Hospital.


All participants received cognitive assessments at baseline and their family caregivers reported neuropsychiatric symptoms at study baseline and at one follow-up visit within 6–18 months of the initial evaluation. The general demographics and prescribed medications, including cholinesterase inhibitors, antipsychotics, antidepressants, antiepileptic drugs, and benzodiazepines, were collected at baseline and during follow-up.



The MMSE24 is one of the most widely used screening instruments for dementia and provides a total score ranging from 0 to 30, with lower scores indicative of greater cognitive impairment. It was administered to patients to obtain an overall level of current cognitive function.


The CVFT25 is a test of verbal initiation ability with good reliability and validity,25 and is commonly used as an ‘executive function measure’ in the assessment of frontal systems functioning.14,15 It also provides some estimate of the integrity of semantic memory. Although impairments of both category and letter fluency tasks have been evaluated in patients with AD, one study had shown that patients with AD exhibit disproportionately greater impairment in category fluency.26 In addition, letter fluency is a more biased test than category fluency when applied in countries that do not use an alphabet language, such as China. Each patient was asked to name as many items as possible in 1 min in the vegetables category.

Constructional Praxis

The Constructional Praxis Test was adopted from the Consortium to Establish a Registry for Alzheimer's Disease (CERAD).27 It measures visuospatial and constructional abilities and requires the subject to copy four line drawings presented in order of increasing complexity (circle, diamond, overlapping rectangles, and cube). The Constructional Praxis score is the number of correctly drawn figures.

Delayed Word Recall Test

The 12-item Delayed Word Recall Test, modified from Rey Auditory–Verbal Learning Test,28 is a measure of verbal memory and involves the repeated administration of a series of lists of 12 words across three learning trials. The delay recall score is the total number of words reported correctly after a 15-min delay.

The Clinical Dementia Rating Scale

The severity of dementia is defined according to the Clinical Dementia Rating (CDR) Scale.29 The CDR is based on inquiry from patients or informants concerning six areas of cognitive function. Each cognitive ability is scored as 0 = normal, 0.5 = questionable, 1 = mild impairment, 2 = moderate impairment, and 3 = severe impairment, from which an overall stage of dementia is derived. The CDR has a range of 0–5; higher scores indicate more severe dementia.

Neuropsychiatric Inventory

The Neuropsychiatric Inventory30 (NPI) was developed for the assessment of behavioral and psychological symptoms in neurodegenerative disorders and has been translated into a variety of languages, including Chinese, with proven validity and reliability.31 The current version evaluates 12 neuropsychiatric symptoms observed in dementia: delusions, hallucinations, aggressiveness, depression, anxiety, euphoria, apathy, disinhibition, irritability, aberrant motor behavior, night-time behaviors, and appetite disturbances. The severity and frequency of each symptom are scored on the basis of structured questions administered to the patient's caregiver. The score for each symptom is obtained by multiplying severity by frequency. A global score for the NPI was generated by summing the total scores of the individual subscales. We also obtained the sub-scores from four subdomains of the NPI, which include hyperactivity, psychosis, affection, and apathy, according to previous studies.32 The hyperactivity subdomain consists of agitation, disinhibition, irritability, and aberrant motor behavior. The psychosis subdomain includes delusion, hallucination, and night-time behavior disturbance. The affection subdomain is comprised of anxiety and depression, and the apathy subdomain includes apathy and appetite/eating abnormalities.

Statistical analysis

Study data were analyzed using spss Version 15.0 (spss, Chicago, IL, USA). The change in behavioral symptom scores (NPI change) was the primary outcome of interest and it was defined as the NPI score during the follow-up minus the NPI score at baseline. A higher NPI change indicates worsening of behavioral problems. The correlation analysis was used to evaluate the associations between the change in NPI scores and the initial assessment of MMSE scores, CVFT scores, Constructional Praxis scores, Delayed Word Recall scores, gender, years of education, patient age, baseline NPI scores, and use of medication for behavioral symptoms (cholinesterase inhibitors, antipsychotics, antidepressants, antiepileptic agents, and benzodiazepines). Spearman's rank correlation analyses were used for non-parametric data and Pearson's correlation analyses were used for parametric data. Histograms for residuals of the dependant variables were plotted, and in all cases there was a normal or near-normal distribution. Comparisons for continuous variables were carried out using the t-test or anova when appropriate. Multivariate linear regression modeling was used to investigate the factors contributing to the changes in NPI total scores and four subdomain scores. Time in months between initial and follow-up assessments, age, education, gender, and baseline NPI total score were included as covariates in the model. Two-tailed tests were used throughout the study and a P-value less than 0.01 was considered statistically significant after balancing the risk of Type I and Type II errors.


  1. Top of page
  2. Abstract
  6. Conflicts of interest declaration
  7. Description of authors' roles

Participants and baseline evaluation

A total of 101 patients (57 women and 44 men) with AD were enrolled. The demographics and results of the baseline evaluation are shown in Table 1. The mean interval before follow-up was 10.1 ± 4.2 months. Seventy-four patients (73%) had mild dementia (CDR = 1), twenty-four patients (24%) had moderate dementia (CDR = 2), and three patients (3%) had severe dementia (CDR = 3). The baseline frequencies of individual neurobehavioral symptoms based on the NPI results were as follows: delusion, 33%; hallucination, 14%; agitation, 36%; depression, 39%; anxiety, 26%; euphoria, 8%; apathy, 43%; disinhibition, 19%; irritability, 40%; aberrant behavior, 26%; night-time problem, 38%; and appetite disturbance, 36%. The frequency of having at least one item of behavioral disturbance was 84%. Among the participants, 26% had taken acetylcholinesterase inhibitors, 7% had taken antipsychotic agents, 4% had taken antidepressants, 1% had taken antiepileptics, and 4% had taken benzodiazepines at baseline. The baseline MMSE scores were correlated with the CVFT scores (Pearson's correlation: r = 0.54, P < 0.001). There was no significant association between baseline NPI and CVFT scores (Spearman's correlation: ρ = −0.17, P = 0.10) or MMSE scores (Spearman's correlation: ρ = −0.11, P = 0.24).

Table 1.  Characteristics of the studied patients at baseline
Baseline characteristicsMean (range) or n (%)
  1. CDR, Clinical Dementia Rating Scale; CVFT, Category Verbal Fluency Test; MMSE, Mini-Mental State Examination; NPI, Neuropsychiatry Inventory.

Age (years)77.6 ± 7.7 (54–96)
Education (years)8.6 ± 4.9 (0–16)
Sex (male)44 (44%)
Married71 (70%)
Duration of follow up (months)10.1 ± 4.2 (6–18)
MMSE scores18.6 ± 5.6 (0–27)
CVFT scores7.1 ± 3.9 (0–16)
Delayed Word Recall scores2.0 ± 2.3 (0–8)
Constructional Praxis scores3.0 ± 0.9 (0–4)
NPI scores
Total score10.9 ± 13.8 (0–76)
 Hyperactivity subdomain score4.0 ± 6.6 (0–34)
 Psychosis subdomain score2.5 ± 3.9 (0–20)
 Affection subdomain score1.6 ± 3.0 (0–18)
 Apathy subdomain scores2.9 ± 3.9 (0–16)

Follow-up results

At follow up, the mean NPI total score was 14.0 ± 17.6 (range 0–91), and the subdomain scores were 4.9 ± 7.9 for hyperactivity, 3.7 ± 5.2 for psychosis, 2.0 ± 4.3 for affection, and 3.4 ± 4.5 for apathy. The mean score of NPI change was 3.1 ± 14.2 (range, −38 to 45). The mean changes in the subdomain scores were 0.9 ± 6.0 (range, −22 to 21) for hyperactivity, 1.2 ± 4.3 (range, −11 to 15) for psychosis, 0.4 ± 3.9 (range, −12 to 24) for affection, and 0.6 ± 4.8 (range, −12 to 16) for apathy. Among our patients, 92% had taken acetylcholinesterase inhibitors, 15% had taken antipsychotic agents, 10% had taken antidepressants, 1% had taken antiepileptics, and 14% had taken benzodiazepines at follow up.

Correlates of NPI change

There were significant correlations between the changes in NPI total score and CVFT score (Pearson's correlation: r = −0.28, P = 0.005), but not in MMSE score (Pearson's correlation: r = −0.08, P = 0.42), Delayed Word Recall score (Pearson's r = −0.17, P = 0.08), and Constructional Praxis score (Pearson's r = −0.08, P = 0.44). There were no significant associations between NPI changes scores and caregiver's age (Pearson's r = −0.04, P = 0.72), gender (P = 0.90, by t-test), educational years (Pearson's r = −0.01, P = 0.89), living with patient or not (P = 0.52, by t-test), and severity of dementia at baseline by clinical dementia rating scale (P = 0.98; by anova).

The changes in the apathy subdomain scores were associated with the baseline NPI subdomain scores (Pearson's correlation: r = −0.48, P = 0.001), and the relationships were borderline between the other three baseline NPI subdomain scores and their changes (Pearson's correlation: hyperactivity, r = −0.21, P = 0.04; psychosis, r = −0.20, P = 0.05; affection, r = −0.24, P = 0.02). There were no associations between changes in NPI total scores and age, gender, years of education, follow-up duration, or usage of psychotropic agents at baseline and follow up. Among the four NPI subdomains, the CVFT score was significantly associated with the changes in the psychosis subdomain score only (Pearson's correlation: r = −0.32, P = 0.001).

Predictors of the changes in NPI scores

The results of the multivariate regression analyses are shown in Table 2. The baseline CVFT score was a significant predictor of the total NPI change score and remained significant after controlling for demographic data, baseline NPI scores, and baseline CDR (standardized regression coefficient = −0.32, t = −3.0, R2 = 0.17, P = 0.004). Regarding the four NPI subdomains, the CVFT score was only predictive of the change in the psychosis subdomain (standardized regression coefficient = −0.34, t = −3.6, R2 = 0.30, P = 0.001), while the relationship was not significant for the other three subdomains.

Table 2.  Estimates of general linear models with changes in NPI total/subdomain scores as dependent variables and CVFT or MMSE as the independent variable
 Total NPI changeHyperactivity subscore changePsychosis subscore changeAffection subscore changeApathy subscore change
  • *

    P value < 0.01.

  • Adjusted according to baseline NPI score, baseline Clinical Dementia Rating and demographic data (age, gender, years of education, and duration of follow up).

  • The values shown in the table are standardized partial regression coefficients.

  • All models without adjustment: d.f. = 1; all models with adjustment: d.f. = 7.

  • CVFT, Category Verbal Fluency Test; NPI, Neuropsychiatry Inventory; MMSE, Mini-Mental State Examination.

 Non adjustment−0.08−0.11−
 Non adjustment−0.28*−0.22−0.32−0.22−0.08
 With adjustment−0.32*−0.26−0.34*−0.26−0.18


  1. Top of page
  2. Abstract
  6. Conflicts of interest declaration
  7. Description of authors' roles

The present study showed that poor performance on baseline CVFT was independently associated with a more rapid progression in overall neuropsychiatric manifestations at follow up, particularly in the psychosis domain among patients with AD. However, initial MMSE scores, the Delayed Word Recall test scores, and CERAD Constructional Praxis scores were not associated with the change of behavioral disturbance. The MMSE is considered as a tool for general cognitive function evaluation, whereas, the Verbal Fluency Test, is considered as a tool for semantic memory and executive function. Our results indicated that poor performance in these cognitive parts may be more specific and related to changes in behavioral disturbance rather than global cognition, verbal memory and visuospatial function.

Some tests for executive function were also useful for predicting the progression of BPSD. Our finding is similar to a recent study among mild demented patients (mean MMSE score 22.5), which suggested that very early frontal executive impairment, tested by the revised Cambridge Cognitive Examination Executive Function score, but not global cognitive function, was related to subsequent behavior disturbance.12 Another study reported that patients with executive dysfunction tested by a series of six cancellation tasks and the time to complete the first three mazes from the expanded Alzheimer's Disease Assessment Scale–Cognitive Subscale had more frequent symptoms of psychosis than those without.33 As the mean MMSE scores demonstrate (mean MMSE score 18.6), our memory clinic sample was relatively moderately cognitively impaired at initial assessment with a high prevalence rate (83%) of behavioral and psychological symptoms, which is compatible with most previous studies because BPSD is common in patients with AD.32 Our study supports the theory that executive dysfunction has a negative influence on the neuropsychiatric symptoms in AD, and extends the finding from patients with very early AD to those in later stages of the disease.

Many factor analytic methods have been used to explore sub-syndromes contained within the NPI due to heterogeneity of the BPSD symptoms in patients with AD.34 In the subdomain analysis, CVFT at baseline could only predict the changes in psychosis. Some reports demonstrated the correlations between frontal lobe function and human behavior,35 and the dysfunction involved in distinct parallel circuits within frontal–subcortical circuits may be the reason for this difference. The lesion of dorsolateral prefrontal circuit involved mainly in executive function is related with the performances of verbal fluency,35,36 and psychosis in AD patients has also been reported to be associated with the same circuit in previous studies.37 Consistent with previous studies on dementia, our findings may indicate that the psychosis domain contributed substantially to the association between BPSD and executive function.38 In addition, the studies on patients with psychosis symptoms also revealed the association between psychosis and verbal fluency and showed that severity of delusions was related to semantic fluency in schizophrenia and bipolar disorders.39 The deficits in CVFT and the worsening of psychosis in AD may share closer pathophysiological processes than the changes in other subdomains of behavioral disturbance.

We did not find any associations between baseline behavioral symptoms and baseline cognitive function results, which supports prior reports that cognitive and behavioral disturbances are either independent dimensions or that they have a weak linkage.33,40 Nevertheless, we found associations between baseline CVFT score and the changes in behavioral symptoms. A possible explanation of these findings is that the correlations between baseline behavioral symptoms and baseline cognition are different from those between changes in behavior and cognition. However, reasons for this finding are still unclear and need further research.

Limitations are addressed here when interpreting the results. Because few cognitive function tests were administered, this study cannot provide a comprehensive cognitive assessment of the change in behavioral symptoms and cognitive function across the full range of cognitive function. Although we tried to control most of the confounding factors, it might not be enough. The sample size is modest with a relatively short duration of follow up, which might not be long enough to evaluate whether any changes occurred with time. The neuropsychological assessment evaluated the prevalence within one prior month, without taking into account the duration of fluctuation over a longer period from baseline. Our study only enrolled subjects with AD, which may limit its application to other types of dementia.

The CVFT has been recommended as a useful instrument for AD among multidimensional investigations.16,18–20 Our study found that the CVFT was related to the change in BPSD and can be used as a simple and practical tool in clinical practice.

Description of authors' roles

  1. Top of page
  2. Abstract
  6. Conflicts of interest declaration
  7. Description of authors' roles

J. L. Fuh designed the study, supervised the data collection and C. F. Tsai wrote the paper. S. J. Wang and J. L. Fuh collected the data and assisted in writing the article (or editing the paper). C. F. Tsai and L. Zheng carried out the statistical analyses.


  1. Top of page
  2. Abstract
  6. Conflicts of interest declaration
  7. Description of authors' roles

This study was supported in part by grants from the National Science Council of Taiwan (97-2314-B-075-049-MY3) and Taipei Veterans General Hospital (V99C1-047).


  1. Top of page
  2. Abstract
  6. Conflicts of interest declaration
  7. Description of authors' roles
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