A key message from the review of cognitive dysfunction in psychiatry published by Millan et al (2012) was not just that cognitive skills are often compromised in patients with psychiatric disorders, but that deficits in specific domains are common to a number of conditions. The review also highlighted that the magnitude of the observed deficits varied across disorders. A helpful element of the Millan et al study was the inclusion of a table in which the authors sought to convey the domains of cognition and a categorization of the magnitude of the observed deficits.

In previous articles, we have considered best practice for the assessment of cognition. In these contributions, we have argued not for the use of specific tests, but instead for measures that meet acceptable standards of reliability, validity, and sensitivity. In the course of our discussions, we have included reference to test validity in the context of considering whether selected measures index appropriate domains of cognition. In this article, we begin with a brief discussion of the requirements for good test selection, especially with respect to issues of sensitivity, reliability, and validity. Thereafter the focus of this article is on the issue of domain validity. We will critically review the specification of the cognitive domains proposed by Millan et al, as well as those selected by authors of meta-analyses characterizing cognitive deficits in major depressive disorders. This focus is solely to make the discussion tractable, though we propose that the issues raised will be applicable across all psychiatric and neurological disorders.

Several studies have demonstrated that psychomotor retardation is an important sign of the major depressive episode, both from a diagnostic point of view and as a predictor of treatment outcome. However, it is uncertain to what extent psychomotor retardation is specific for the major depressive episode. A heterogeneous group of psychiatric patients (n=26) was studied using a rating scale developed specifically to assess psychomotor retardation (RRS). The 13 patients suffering from a major depressive episode had a significantly higher RRS score than patients with another diagnosis. Furthermore, in the depressive subjects the severity of the depression (measured by means of Hamilton's depression rating scale) appeared to correlate with the severity of the psychomotor retardation. Cognitive features of psychomotor retardation were mainly responsible for the more severe psychomotor retardation in the depressive patients. Surprisingly. Hamilton's depression scale which was used in this study does not pay much attention to these aspects.

We tested the hypothesis that maternal worm infections in pregnancy affect infant motor and neurocognitive development, and that anthelminthic treatment during pregnancy can reverse these effects. We used measures which examine infant motor, cognitive and executive function, including inhibition. We assessed 983 Ugandan infants aged 15 months, using locally appropriate measures within the Entebbe Mother and Baby Study, a trial of anthelminthic treatment during pregnancy. Key exposures were maternal worm infections and anthelminthic treatment during pregnancy. Effects of other health and social factors were controlled for statistically. Of the five major worm species found in the pregnant women, two had influences on the developmental measures: Maternal Mansonella perstans and Strongyloides stercoralis infections showed negative associations with the A-not B-task, and Language, respectively. Performance on other psychomotor and cognitive measures was associated with illnesses during infancy and infants’ behavior during assessment, but not with maternal worm infections. There were no positive effects of maternal anthelminthic treatment on infant abilities. Mansonella perstans and Strongyloides stercoralis infection during pregnancy seem associated with impaired early executive function and language, respectively, but single-dose anthelminthic treatment during pregnancy was not beneficial. The biological mechanisms that could underlie these neurocognitive effects are discussed. (JINS, 2012, 18, 1019–1030)

The nature of residual cognitive deficits after out of hospital cardiac arrest (OHCA) is incompletely described and has never been defined against a cardiac control (CC) group. The objective of this study is to examine neuropsychological outcomes 3 months after OHCA in patients in a “middle range” of acute severity. Thirty prospective OHCA admissions with coma >1 day and responsive but confused at 1 week, and 30 non-OHCA coronary care admissions were administered standard tests in five cognitive domains. OHCA subjects fell into two deficit profiles. One group (N = 20) had mild memory deficits and borderline psychomotor deficits compared to the CC group; 40% had returned to work. The other group (N = 10) had severe impairments in all domains. Coma duration was associated with group. Neither group had a high prevalence of depression. For most patients within the “middle range” of acute severity of OHCA, cognitive and functional outcomes at 3 months were encouraging. (JINS, 2011, 17, 364–368)

While the majority of seniors live outside of institutions, many live in seniors apartment buildings rather than in single family dwellings. MacPherson (1983) suggested that not maintaining an independent living style may have some negative consequences for seniors. The question asked was whether differences in lifestyle arising from the nature of the residence were associated with measures of psychomotor performance. Some 36 seniors, average age approximately 68 yrs., all in good health, completed 800 responses on a discrete pursuit tracking task which emphasized response speed and accuracy. Significant differences in performance were noted for both RT and speed of movement. Overall, seniors living independently, either in urban or rural areas, responded faster than seniors living in seniors apartment buildings. The data do not imply a causal relationship, however, they do suggest that psychomotor variables are relevant factors to consider in regard to differing living styles.

Mild cognitive impairment (MCI) is a classification reserved for nondemented elderly individuals at increased risk for future decline to dementia, compared to those with normal cognition. Cognitive tests, particularly those assessing verbal recall, have been found to be useful in the identification of elderly people with MCI. We argue that a variety of motor/psychomotor evaluations are also sensitive to MCI. Motor assessments described as complex correctly categorize normal versus MCI elderly with comparable accuracies to those obtained by cognitive tests. Unlike performance on verbally based cognitive measures, motor-test scores appear to be relatively independent of educational attainment, indicating that the use of certain motor tests may be particularly valuable in the identification of MCI among elderly with widely varying educational backgrounds.

Most popular tests of motor proficiency have been developed using classical test theory. Recently, item response theory (IRT) has been used to address some of the difficulties inherent with these traditional psychometric approaches. This paper focuses on the application of IRT in the psychomotor domain where analyses involving both dichotomous (Cole, Wood, & Dunn, 1991; Werder & Bruininks, 1988) and polytomous criterion referenced measurements (Puderbaugh & Fisher, 1992) have met with equivocal results. The application of the method to quantitative data has to date proved challenging. An example reported here is based on outcome measures used in the development of a test of movement skills for children aged 5 and 6 years. The results appear very promising, but some caution is required in interpreting results.