Performance and Symptom Validity Assessment in Patients with Apathy and Cognitive Impairment.

OBJECTIVE: Performance and symptom validity tests (PVTs and SVTs) measure the credibility of the assessment results. Cognitive impairment and apathy potentially interfere with validity test performance and may thus lead to an incorrect (i.e., false-positive) classification of the patient's scores as non-credible. The study aimed at examining the false-positive rate of three validity tests in patients with cognitive impairment and apathy. METHODS: A cross-sectional, comparative study was performed in 56 patients with dementia, 41 patients with mild cognitive impairment, and 41 patients with Parkinson's disease. Two PVTs - the Test of Memory Malingering (TOMM) and the Dot Counting Test (DCT) - and one SVT - the Structured Inventory of Malingered Symptomatology (SIMS) - were administered. Apathy was measured with the Apathy Evaluation Scale, and severity of cognitive impairment with the Mini Mental State Examination. RESULTS: The failure rate was 13.7% for the TOMM, 23.8% for the DCT, and 12.5% for the SIMS. Of the patients with data on all three tests (n = 105), 13.5% failed one test, 2.9% failed two tests, and none failed all three. Failing the PVTs was associated with cognitive impairment, but not with apathy. Failing the SVT was related to apathy, but not to cognitive impairment. CONCLUSIONS: In patients with cognitive impairment or apathy, failing one validity test is not uncommon. Validity tests are differentially sensitive to cognitive impairment and apathy. However, the rule that at least two validity tests should be failed to identify non-credibility seemed to ensure a high percentage of correct classification of credibility.

The Diagnostic and Prognostic Value of Neuropsychological Assessment in Memory Clinic Patients.

BACKGROUND: Neuropsychological testing has long been embedded in daily clinical practice at memory clinics but the added value of a complete neuropsychological assessment (NPA) to standard clinical evaluation is unknown. OBJECTIVE: To evaluate the added diagnostic and prognostic value of NPA to clinical evaluation only in memory clinic patients. METHODS: In 221 memory clinic patients of a prospective cohort study, clinical experts diagnosed clinical syndrome (subjective cognitive impairment (SCI), mild cognitive impairment (MCI), or dementia) and etiology (Alzheimer's disease (AD) or no AD), and provided a prognosis of disease course (decline or no decline) before and after results of NPA were made available. The reference standard was a panel consensus based on all clinical information at baseline and up to 2 follow-up assessments. RESULTS: With NPA data available, clinicians changed their initial syndromal diagnosis in 22% of patients, and the etiological diagnosis as well as the prognosis in 15%. This led to an increase in correctly classified cases of 18% for syndromal diagnosis, 5% for etiological diagnosis, and 1% for prognosis. NPA data resulted in the largest improvement in patients initially classified as SCI (syndrome: 93.3% (n = 14) correctly reclassified, etiology: net reclassification improvement [NRI] = 0.61, prognosis: NRI = 0.13) or MCI (syndrome: 89.3% (n = 23) correctly reclassified, etiology: NRI = 0.17, prognosis: NRI = 0.14), while there was no improvement in patients with dementia (syndrome: 100% (n = 1) correctly reclassified, etiology: NRI = -0.05, prognosis: NRI = -0.06). Overall, inclusion of NPA in the diagnostic process increased confidence in all diagnoses with 6-7%. CONCLUSION: Administration of a complete NPA after standard clinical evaluation has added value for diagnosing cognitive syndrome and its underlying etiology in patients regarded as non-demented based on the first clinical impression.

Assessment of depression in Parkinson's disease: the contribution of somatic symptoms to the clinimetric performance of the Hamilton and Montgomery-Asberg rating scales.

OBJECTIVE: To assess the influence of somatic symptoms of the Hamilton Depression Rating Scale (HAMD) and Montgomery-Asberg Depression Rating Scale (MADRS) on the clinimetric performance of these scales in patients with Parkinson's disease (PD). METHODS: A total of 224 patients underwent a protocolized mental status examination, consisting of the Structured Clinical Interview for DSM-IV depressive disorder (SCID-D), as well as the HAMD and MADRS. Sensitivity, specificity, positive, and negative predictive values for a range of cut-off scores were calculated for both rating scales and for modified versions of these scales in which all somatic items were eliminated. In addition, receiver operating characteristic (ROC) curves were obtained for both the modified and unmodified scales. RESULTS: Elimination of the somatic items of depression from the HAMD and MADRS resulted in a reduced specificity of both the HAMD and the MADRS, and an increased sensitivity of the MADRS. CONCLUSION: The authors recommend the full version of the HAMD and MADRS if used for diagnostic purposes; for screening purposes, the abbreviated version without somatic items can be used. Additional advantages of using full rating scales, with somatic items included, are that these provide more information on the severity of depression and allow for easier comparison across studies.