Cognitive dysfunctions and pathological gambling in patients with Parkinson's disease

The purpose of this study was to investigate the neuropsychological correlates of pathological gambling (PG) in Parkinson's disease (PD). Fifteen patients with PD affected by PG (identified based on DSM‐IV criteria; PD+PG) without clinically evident dementia were compared with 15 nondemented patients with PD not affected by PG (PD?PG). Two groups of patients with PD were matched for age, length of education, and gender. Clinical and neuropsychiatric features were assessed; several cognitive domains, mainly related to executive functions, were explored by means of standardized neuropsychological tasks. PD+PG and PD?PG did not differ on clinical and neuropsychiatric aspects. PD+PG patients performed significantly worse than PD?PG patients on cognitive tasks that evaluated visuo‐spatial long‐term memory and several frontal lobe functions. After Bonferroni correction, differences remained significant on the Frontal Assessment Battery (FAB) (P = 0.001), on phonological fluency task (P = 0.003), and on the Trail Making Test, part B minus part A (P = 0.002). Logistic regression analysis demonstrated that low scores on the FAB were the only independent predictor of PG (odds ratio, 27.9; 95% CI: 2.82–277.95, P = 0.004). The results indicate an association between PG and frontal lobe dysfunctions in nondemented patients with PD. Low scores on the FAB indicate patients with PD at high risk for PG. © 2009 Movement Disorder Society     

Magnetic resonance imaging findings of shoulders in Parkinson's disease

The aim of this study is to evaluate shoulder disturbances in Parkinson's disease (PD) patients using magnetic resonance imaging (MRI) which is the best tool in the demonstration of complex shoulder pathologies; and to determine probable relations between shoulder pathologies and PD clinical features. Twenty‐eight PD patients with a total of 56 shoulders were used as the study group while 13 age‐matched cases with 26 shoulders were used as the control group (CG) in the study. Both patients with PD and the CG underwent shoulder MRI. The Hoehn and Yahr (H&Y) disability scale and Unified Parkinson's Disease Rated Scale (UPDRS) were used to determine the severity of the disease. Our results showed that patients with full‐thickness supraspinatus (SSP) tear have statistically significant higher UPDRS (P = 0.012), tremor (P = 0.023), rigidity (P = 0.023), and total (P = 0.002) scores. Mild group patients (P = 0.045) showed significantly higher frequency resting tremor and subcoracoid effusion than those of severe group patients (P = 0.002). Subcoracoid effusion was observed in patients with significantly higher UPDRS (P = 0.045) and rigidity (P = 0.022) scores. When the resting tremor and subcoracoid effusion groups were compared according to the severity of the resting tremor but not according to the H&Y, higher frequency of full‐thickness tear in SSP tendon was detected in the group of resting tremor (P = 0.053). Longer duration of disease was also observed in patients with full‐thickness SSP tear (P = 0.029) and acromioclavicular joint changes (P = 0.018). Higher UPDRS, tremor, rigidity and total scores and longer PD duration appear as the predisposing factors for the development of shoulder disturbances in PD in this study. © 2010 Movement Disorder Society     

Frontal assessment battery scores and non-motor symptoms in parkinsonian disorders

Using data from the PRIAMO study, we investigated non-motor symptoms (NMS) versus frontal lobe dysfunction in patients with idiopathic Parkinson disease (PD); 808 patients with PD and 118 with atypical parkinsonisms (AP) were consecutively enrolled at 55 Centers in Italy. Twelve categories of NMS were investigated. Cognitive impairment was defined as a Mini-Mental Status Evaluation score ≤ 23.8 and frontal lobe dysfunction as a Frontal Assessment Battery (FAB) score ≤ 3.48. Multivariable logistic regression was used to identify predictor of frontal lobe dysfunction in 524 PD patients, and a generalized linear model was used for each of the six FAB items. Not only the total FAB scores but also the single FAB items were lower in AP versus PD (p ≤ 0.005). Age (OR = 1.05), cognitive impairment (OR = 9.54), lack of cardiovascular symptoms (OR = 3.25), attention or memory problems (OR = 0.59) and treatment with L: -DOPA (OR = 5.58) were predictors of frontal lobe dysfunction. MMSE was negatively associated with all FAB items (β ≤ -0.16) and age with all FAB items but prehension behavior (β ≤ -0.01). Previous use of L: -DOPA was negatively associated with verbal fluency (β = -0.32) possibly acting as surrogate marker of disease duration. Cognitive impairment is a predictor of frontal lobe dysfunction. Among NMS, lack of attention or memory problems were negatively associated with frontal impairment. Further studies are nonetheless needed to better identify the predictors of frontal impairment in PD patients.     

The Frontal Assessment Battery (FAB) in Parkinson’s disease and correlations with formal measures of executive functioning

BACKGROUND: The Frontal Assessment Battery (FAB) is a short tool for the assessment of executive functions consisting of six subtests that explore different abilities related to the frontal lobes. Several studies have indicated that executive dysfunction is the main neuropsychological feature in Parkinson's disease (PD). GOALS: To evaluate the clinical usefulness of the FAB in identifying executive dysfunction in PD; to determine if FAB scores in PD are correlated with formal measures of executive functions; and to provide normative data for the Portuguese version of the FAB. METHODS: The study involved 122 healthy participants and 50 idiopathic PD patients. We compared FAB scores in normal controls and in PD patients matched for age, education and Mini-Mental State Examination (MMSE) score. In PD patients, FAB results were compared to the performance on tests of executive functioning. RESULTS: In the healthy subjects, FAB scores varied as a function of age, education and MMSE. In PD, FAB scores were significantly decreased compared to normal controls, and correlated with measures of executive functions such as phonemic and semantic verbal fluency tests, Wisconsin Card Sorting Test and Trail Making Test Part A and Part B. CONCLUSION: The FAB is a useful tool for the screening of executive dysfunction in PD, showing good discriminant and concurrent validities. Normative data provided for the Portuguese version of this test improve the accuracy and confidence in the clinical use of the FAB.     

Validation of the freezing of gait questionnaire in patients with Parkinson's disease

To revalidate the Freezing of Gait Questionnaire (FOG‐Q), patients with Parkinson's disease (PD) were randomly assigned to receive rasagiline (1 mg/day) (n = 150), entacapone (200 mg with each dose of levodopa) (n = 150), or placebo (n = 154). Patients were assessed at baseline and after 10 weeks using the FOG‐Q, Unified Parkinson's Disease Rating Scale (UPDRS), Beck Depression Inventory (BDI), and Parkinson's Disease Questionnaire (PDQ‐39). FOG‐Q dimensionality, test–retest reliability, and internal reliability were examined. Convergent and divergent validities were assessed by correlating FOG‐Q with UPDRS, BDI, and PDQ‐39. Comparisons between FOG‐Q item 3 and UPDRS item 14 were also made. Principal component analysis indicated that FOG‐Q measures a single dimension. Test–retest reliability and internal reliability of FOG‐Q score was high. FOG‐Q was best correlated to items of the UPDRS relating to walking, general motor issues, and mobility. Correlations between baseline and endpoint suggested that FOG‐Q item 3 is at least as reliable as UPDRS item 14. At baseline, 85.9% of patients were identified as “Freezers” using FOG‐Q item 3 (≥1) and 44.1% using UPDRS item 14 (≥1) (P < 0.001). FOG‐Q was a reliable tool for the assessment of treatment intervention. FOG‐Q item 3 was effective as a screening question for the presence of FOG. © 2007 Movement Disorder Society     

Serum uric acid levels and freezing of gait in Parkinson’s disease

Uric acid (UA) is a natural antioxidant and iron scavenger in the human body, which has been hypothesized to exert an anti-oxidative effect in Parkinson’s disease (PD). This study aimed to investigate the relationship between serum UA levels and freezing of gait (FOG) in PD. A total of 321 Chinese PD patients with fasting serum UA evaluated were included in the cross-sectional study. Demographics, clinical features, and therapeutic regimen were collected. The Unified PD Rating Scale (UPDRS) III and Hoehn and Yahr (H and Y) stage were used to evaluate the severity of disease, and the Frontal Assessment Battery (FAB) and Montreal Cognitive Assessment (MoCA) scales were used to assess the cognitive function. Patients with FOG showed lower proportion of male, longer disease duration, lower body mass index, lower concentrations of serum UA, higher total levodopa equivalent daily dosage, higher UPDRS III score, greater median H and Y stage, lower scores of FAB and MoCA, and higher frequencies of motor fluctuation, dyskinesia, falls, and festination compared to patients without FOG (P < 0.05). The binary logistic regression model indicated that high UPDRS III score (OR = 1.049, P < 0.001), fluctuation (OR = 2.677, P = 0.035), dyskinesia (OR = 6.294, P = 0.003), festination (OR = 3.948, P < 0.001), falls (OR = 7.528, P < 0.001), and low serum UA levels (OR = 0.990, P < 0.001) were associated with FOG. Our study suggests that low serum UA concentration is associated with the occurrence of FOG in PD.     

Nonmotor symptoms are independently associated with impaired health‐related quality of life in Chinese patients with Parkinson's disease

We performed a cross‐sectional study of 82 Chinese patients with Parkinson's disease (PD) enrolled during an 18‐month period using a clinical interview to assess the prevalence of nonmotor symptoms (NMS), the association with disease severity and motor status, and the impact on patients' health‐related quality of life (Hr‐QoL). The patients' NMS, Hr‐QoL, disease severity, and motor status were assessed by the Nonmotor Symptoms Scale (NMSS), the 39‐item Parkinson's Disease Questionnaire (PDQ‐39), the modified Hoehn and Yahr staging scale (H&Y) and the Unified Parkinson's Disease Rating Scale part III (UPDRS III), respectively. We found that 100% of patients with PD presented with NMS. The NMSS significantly correlated with disease duration (Spearman's r_S = 0.276, P = 0.012), H&Y (r_S = 0.230, P = 0.038), and UPDRS III (r_S = 0.350, P = 0.001). Similarly, the PDQ‐39 SI significantly associated with the disease duration (r_S = 0.258, P = 0.019), H&Y (r_S = 0.340, P = 0.002), and UPDRS III (r_S = 0.453, P < 0.001). NMS domains that influenced the PDQ‐39 SI were sleep/fatigue, mood, gastrointestinal, urinary, and miscellaneous symptoms. This strongly suggested that the five domains played a key role in the manifestation of Hr‐QoL. NMSS explains more of the variability in Hr‐QoL than UPDRS III, when both are the model (stepwise multiple linear regression analysis R² change, 47.8% vs. 5.87%, respectively). Therefore, these findings demonstrate that NMS are independently and negatively associated with Hr‐QoL in PD and that improving NMS should be viewed as an important part in the management of PD. © 2010 Movement Disorder Society     

The applause sign and neuropsychological profile in progressive supranuclear palsy and Parkinson's disease

Background

The applause sign has been associated with various neurodegenerative diseases. We investigate its validity in the differential diagnosis of progressive supranuclear palsy and Parkinson's disease, and its relationship with neuropsychological tests.

Patients and methods

23 patients with progressive supranuclear palsy and 106 patients with Parkinson's disease were included and administered the following scales: progressive supranuclear palsy rating scale, unified Parkinson's disease rating scale (UPDRS), mini-mental state examination (MMSE), frontal assessment battery (FAB), neuropsychiatric inventory and three-clap test.

Results

73.9% with progressive supranuclear palsy and 21.7% with Parkinson's disease showed a positive applause sign. Only a positive applause sign, UPDRS II score and disease duration were found to be predictors of progressive supranuclear palsy. Both patient-groups showed statistically significant correlations between the applause sign and neuropsychological tests: in progressive supranuclear palsy patients MMSE correlation coefficient: 0.62 (p: 0.002) and FAB correlation coefficient: 0.48 (p: 0.02), and in Parkinson's disease patients MMSE correlation coefficient: 0.47 (p < 0.001) and FAB correlation coefficient: 0.43 (p < 0.001). Verbal fluency and inhibitory control (FAB) and writing and orientation in time (MMSE) discriminated between patients with normal and positive applause sign.

Conclusions

A positive applause sign is not specific to progressive supranuclear palsy and may also be observed in Parkinson's disease patients with altered cognition, and it's related to cortical frontal abnormalities such as language disorders and inhibitory control.     

Freezing of gait affects quality of life of peoples with Parkinson's disease beyond its relationships with mobility and gait.

The aim of this study was to examine the association between freezing of gait (FOG) and quality of life (QoL) in patients with Parkinson's disease (PD). PD patients (n = 118) completed the PDQ-39 (QoL) and FOG-Q questionnaires. Disease severity was assessed by the Hoehn and Yahr (H&Y) staging and the Unified Parkinson's Disease Rating Scale (UPDRS). The relations between those parameters were assessed using regression models. 66 men and 52 women (mean age 65.8 +/- 10.2 years, UPDRS total score 48.4 +/- 17.1, disease duration 8.5 +/- 5.8 years, H&Y stage 2.7 +/- 0.8) participated. FOG severity had a significant effect on QoL (P < 0.0015), accounting for disease severity assessed by UPDRS. Specifically, FOG severity was correlated with all the dimensions of the PDQ-39 except for stigma and social support, as follows: with mobility, bodily discomfort, activity of daily living (ADL) (P < 0.005 in all), with emotional, communication, and cognition (P < 0.05 in all). FOG severity (FOG-Q) was also found to affect a modified PDQ total score, without the mobility aspect (P = 0.0081). FOG should be viewed as a highly important symptom with regard to QoL of PD patients beyond its effect on gait and mobility. On the basis of the present results, special attention should be given to FOG in the treatment of patients with PD.     

Deep Brain Stimulation for Early-Stage Parkinson’s Disease: An Illustrative Case

Objectives: Subthalamic nucleus (STN) deep brain stimulation (DBS) is an effective intervention in advanced Parkinson's disease (PD), but its efficacy and safety in early PD are unknown. We are conducting a randomized pilot trial investigating DBS in early PD. This report describes one participant who received bilateral STN‐DBS. Materials and Methods: Thirty subjects have been randomized to either optimal drug therapy (ODT) or DBS + ODT. Microelectrode recordings from the STN and substantia nigra are collected at implantation. The Unified Parkinson's Disease Rating Scale Motor Subscale (UPDRS‐III) is administered in the ON and OFF states semi‐annually and neuropsychological function and quality of life are assessed annually. We describe a 54‐year‐old man with a two‐year history of PD who was randomized to DBS + ODT and followed for two years. Results: The subject showed a lower STN to substantia nigra ratio of neuronal activity than advanced PD patients, and higher firing rate than non‐PD patients. The subject's total UPDRS and UPDRS‐III scores improved during the two‐year follow‐up, while his OFF UPDRS‐III score and levodopa equivalent daily dose increased. Quality of life, verbal fluency, and verbal learning improved. He did not experience any serious adverse events. Conclusions: This report details the first successful application of bilateral STN‐DBS for early‐stage PD during a clinical trial.     

Freezing of Gait Questionnaire: validity and reliability of the Swedish version

Background – Patient‐reported assessments of freezing of gait (FOG) in Parkinson’s disease (PD), such as the FOG questionnaire (FOGQ), are needed because FOG is difficult to assess objectively. However, the measurement properties of the FOGQ have been sparsely assessed. Aim – To assess the measurement properties of the Swedish FOGQ, and to explore relationships between FOGQ scores and other aspects of PD. Methods – Thirty‐seven people with PD were assessed with the FOGQ, Unified PD Rating Scale (UPDRS), Hoehn and Yahr (HY), Falls‐Efficacy Scale [FES(S)], timed gait tests, and the SF‐36 physical functioning (PF) scale. Results – Mean (SD) FOGQ item scores ranged between 1.3 and 2.1 (1.2–1.5); corrected item–total correlations ranged between 0.80 and 0.94. Reliability was 0.95. Mean (SD) and median (q1–q3) FOGQ scores were 9.6 (7.4) and 10 (2–15). Floor and ceiling effects were ≤5.4%. FOGQ correlated strongest with UPDRS part II (ADL), UPDRS item 14 (freezing), and HY (r_S 0.65–0.66). FOGQ scores correlated with PD duration, the Timed Up and Go test, dyskinesia, motor fluctuations, FES(S), and PF scores (r_S 0.40–0.62). Fallers had higher FOGQ scores than non‐fallers (median 12.5 vs 5.0). Conclusion – Data support the measurement properties of the Swedish FOGQ by replicating and extending previous psychometric reports.     

Phonemic verbal fluency decline after subthalamic nucleus deep brain stimulation does not depend on number of microelectrode recordings or lead tip placement

BackgroundEvidence suggests that both motor improvement and decline in verbal fluency in Parkinson's disease (PD) patients undergoing deep brain stimulation (DBS) may be attributed to a lead implantation effect.ObjectiveWe investigated whether the number of microelectrode recording (MER) passes influenced either motor UPDRS scores just prior to stimulation initiation at 4 weeks or decline in verbal fluency 6–24 months after surgery.MethodsWe retrospectively analyzed 50 PD patients who underwent bilateral STN DBS. Off medication UPDRS III motor scores were obtained before surgery and before stimulation was initiated. Neuropsychological testing was completed pre- and post-operatively in 28 patients at a mean of 377 days. Coordinates of lead tip and active stimulation site were calculated.ResultsThere was no improvement in off-medication UPDRS III motor scores at a mean 33.9 days following surgery, with mean change of 0.04 ± 10.48 (p = 0.98). There was no correlation between the number of MER passes and change in individual UPDRS motor score (r = −0.0001, p = 1.0). We observed significant decline in phonemic verbal fluency by 16% (p = 0.003) but it was not correlated with number of left hemisphere (r = −0.15, p = 0.46), or total number of passes (r = −0.02, p = 0.94) or coordinates of the lead tip or active stimulation site. There was a trend toward correlation with age (r = 0.38, p = 0.07).ConclusionsSignificant decline in phonemic verbal fluency did not correlate with surgical passes nor with location of the lead tip or active stimulation site. These data suggest that age may influence verbal fluency decline more than surgical technique.     

Speech and gait in Parkinson's disease: When rhythm matters

IntroductionSpeech disturbances in Parkinson's disease (PD) are heterogeneous, ranging from hypokinetic to hyperkinetic types. Repetitive speech disorder has been demonstrated in more advanced disease stages and has been considered the speech equivalent of freezing of gait (FOG). We aimed to verify a possible relationship between speech and FOG in patients with PD.MethodsForty-three consecutive PD patients and 20 healthy control subjects underwent standardized speech evaluation using the Italian version of the Dysarthria Profile (DP), for its motor component, and subsets of the Battery for the Analysis of the Aphasic Deficit (BADA), for its procedural component. DP is a scale composed of 7 sub-sections assessing different features of speech; the rate/prosody section of DP includes items investigating the presence of repetitive speech disorder. Severity of FOG was evaluated with the new freezing of gait questionnaire (NFGQ).ResultsPD patients performed worse at DP and BADA compared to healthy controls; patients with FOG or with Hoehn-Yahr >2 reported lower scores in the articulation, intellibility, rate/prosody sections of DP and in the semantic verbal fluency test. Logistic regression analysis showed that only age and rate/prosody scores were significantly associated to FOG in PD. Multiple regression analysis showed that only the severity of FOG was associated to rate/prosody score.ConclusionsOur data demonstrate that repetitive speech disorder is related to FOG and is associated to advanced disease stages and independent of disease duration. Speech dysfluency represents a disorder of motor speech control, possibly sharing pathophysiological mechanisms with FOG.     

Neuropsychological changes 1-year after subthalamic DBS in PD patients: A prospective controlled study

ObjectiveThis study aimed at investigating the neuropsychological effect of DBS of the Subthalamic Nucleus in patients with advanced Parkinson's disease (PD).MethodsA standardized neuropsychological test battery, assessing reasoning, memory and executive functions, was administered to 27 PD patients who underwent DBS-STN (DBS group) and to a matched control group of 31 PD patients under optimal medical treatment (MED group). Patients were evaluated at baseline and at the end of 1 year.ResultsChange score analysis (T1 minus T0 scores) demonstrated a significant decline in phonemic verbal fluency in the DBS group compared with the MED group (p < 0.005), while there were no significant changes between the two groups for the other cognitive tests. Single cases analysis by means of multivariate normative comparisons revealed that 4 out of 27 DBS patients (15%) showed cognitive deterioration one year post surgery. These patients were significantly more compromised from a motor standpoint (UPDRS, section III) than the 23 DBS PD patients who had no cognitive decline post surgery.ConclusionResults of this prospective controlled-study showed that phonemic verbal fluency declined one year after DBS-STN, while the other cognitive domains did not change significantly. Nevertheless, single case analysis highlighted the fact that a subgroup comprising 15% of DBS-STN patients (4/27) showed significant cognitive decline 1 year after surgery.     

Association between cognitive impairment and gait disturbance in patients with idiopathic normal pressure hydrocephalus

We compared the scores of the Frontal Assessment Battery (FAB), initial fluency subtest, category fluency subtest and subtests of the Mini-Mental State Examination (MMSE) between patients with idiopathic normal pressure hydrocephalus (iNPH) and age-, sex- and MMSE-matched patients with Alzheimer's disease (AD). In patients with iNPH, the time and number of steps required to go and come back a 10-meter distance were measured (Walking test) and the associations between the scores of the cognitive tests and the performance of the Walking test were evaluated. The scores of the FAB and initial fluency subtest in patients with iNPH were significantly lower than those in patients with AD. The scores of the FAB, initial fluency subtest and serial 7 subtest of the MMSE significantly correlated with the two scores of the Walking test in patients with iNPH. The present results indicate that frontal lobe functions were impaired in patients with iNPH and that cognitive impairment was closely associated with gait disturbance in patients with iNPH.     

Investigation of supervisory attentional system functions in patients with Parkinson''s disease using the Hayling task

The study explored executive dysfunction in Parkinson's disease (PD) by using the Hayling test (Burgess & Shallice, 1996) and verbal fluency tasks (VFTs). PD patients showed longer response latencies than controls in both parts of the Hayling test (Section A/automatic and Section B/inhibition). Patients and controls did not differ in the proportion of errors or number of responses that revealed the use of strategies. PD patients also showed verbal fluency deficits in semantic, phonemic, and alternating fluency tasks. These impairments on tests known to be sensitive to frontal lobe dysfunction confirm executive or Supervisory Attentional System (Norman & Shallice, 1986) deficits and further indicate suppression skills impairments in PD.     

Investigation of Supervisory Attentional System Functions in Patients With Parkinson’s Disease Using the Hayling Task

The study explored executive dysfunction in Parkinson’s disease (PD) by using the Hayling test (Burgess & Shallice, 1996) and verbal fluency tasks (VFTs). PD patients showed longer response latencies than controls in both parts of the Hayling test (Section A/automatic and Section B/inhibition). Patients and controls did not differ in the proportion of errors or number of responses that revealed the use of strategies. PD patients also showed verbal fluency deficits in semantic, phonemic, and alternating fluency tasks. These impairments on tests known to be sensitive to frontal lobe dysfunction confirm executive or Supervisory Attentional System (Norman & Shallice, 1986) deficits and further indicate suppression skills impairments in PD.     

Explaining freezing of gait in Parkinson's disease: Motor and cognitive determinants

Freezing of gait (FOG) is part of a complex clinical picture in Parkinson's disease (PD) and is largely refractory to standard care. Diverging hypotheses exist about its origins, but a consolidated view on what determines FOG is lacking. The aim of this study was to develop an integrative model of FOG in people with PD. This cross‐sectional study included 51 Parkinson subjects: 24 patients without FOG and 27 with FOG matched for age, gender, and disease severity. Subjects underwent an extensive clinical test battery evaluating general disease characteristics, gait and balance, nongait freezing, and cognitive functions. The relative contribution of these outcomes to FOG was determined using logistic regression analysis. The combination of the following four independent contributors provided the best explanatory model of FOG (R² = 0.49): nongait freezing; levodopa equivalent dose (LED); cognitive impairment; and falls and balance problems. The model yields a high‐risk profile for FOG (P > 95%) when Parkinson patients are affected by at least one type of nongait freezing (e.g., freezing of other repetitive movements), falls or balance problems during the last 3 months, and a Scales for Outcomes in Parkinson's Disease‐Cognition score below 28. A high LED further increases the risk of FOG to 99%. Nongait freezing, increased dopaminergic drug dose, cognitive deficits, and falls and balance problems are independent determinants of FOG in people with PD and may play a synergistic role in its manifestation. © 2012 Movement Disorder Society     

Differentiating Alzheimer’s disease from subcortical vascular dementia with the FAB test

Background The frontal assessment battery (FAB) test is a composite tool for assessing executive functions related to the frontal lobe. Neuropsychological and blood-flow studies indicate distinct patterns of deterioration of anterior and posterior cortical function in Alzheimer’s disease (AD) and subcortical vascular dementia (VD) patients. We predict that the FAB score may be useful for discriminating VD from AD. Objective To evaluate the clinical usefulness of the FAB test for differential diagnosis of AD and VD. Methods We compared FAB scores in 25 patients with AD, 27 patients with VD, and 80 age-matched normal control subjects. The AD group was matched for age, education and MMSE score with the VD group. The subtest scores in FAB were also compared among the three groups. Results The FAB scores were significantly decreased in both the AD and VD groups compared to the control group, and the reduction were greater in the VD group. Among the FAB subtests, mental flexibility (phonological verbal fluency) was the only subtest that significantly discriminated VD from the other two groups. Conclusions The FAB test can provide useful information for differentiating AD and VD at the bedside. Received in revised form: 20 January 2006