Assessment of linear and nonlinear/complex heartbeat dynamics in subclinical depression (dysphoria).

OBJECTIVE: Depression is one of the leading causes of disability worldwide. Most previous studies have focused on major depression, and studies on subclinical depression, such as those on so-called dysphoria, have been overlooked. Indeed, dysphoria is associated with a high prevalence of somatic disorders, and a reduction of quality of life and life expectancy. In current clinical practice, dysphoria is assessed using psychometric questionnaires and structured interviews only, without taking into account objective pathophysiological indices. To address this problem, in this study we investigated heartbeat linear and nonlinear dynamics to derive objective autonomic nervous system biomarkers of dysphoria. APPROACH: Sixty undergraduate students participated in the study: according to clinical evaluation, 24 of them were dysphoric. Extensive group-wise statistics was performed to characterize the pathological and control groups. Moreover, a recursive feature elimination algorithm based on a K-NN classifier was carried out for the automatic recognition of dysphoria at a single-subject level. MAIN RESULTS: The results showed that the most significant group-wise differences referred to increased heartbeat complexity (particularly for fractal dimension, sample entropy and recurrence plot analysis) with regards to the healthy controls, confirming dysfunctional nonlinear sympatho-vagal dynamics in mood disorders. Furthermore, a balanced accuracy of 79.17% was achieved in automatically distinguishing dysphoric patients from controls, with the most informative power attributed to nonlinear, spectral and polyspectral quantifiers of cardiovascular variability. SIGNIFICANCE: This study experimentally supports the assessment of dysphoria as a defined clinical condition with specific characteristics which are different both from healthy, fully euthymic controls and from full-blown major depression.

Nonlinear analysis of heart rate variability for the assessment of Dysphoria.

Dysphoric patients show symptoms associated with Major Depression, although within a narrowed symptomatology spectrum. In prevailing practice, clinicians assess Dysphoria through psychological scores and questionnaires exclusively, therefore without taking into account objective biomarkers. In this study, we investigated heartbeat linear and nonlinear dynamics aiming to an objective assessment of Dysphoria. To this end, we derived standard and nonlinear measures from heart rate variability (HRV) series gathered from dysphoric (n=14) and nondysphoric (n=17) undergraduate students during 5 minutes of resting state. We performed both statistical and pattern recognition analyses in order to discern the two groups. Results showed significant group-wise differences in HRV nonlinear metrics exclusively, suggesting a crucial role of nonlinear sympatho-vagal dynamics in Dysphoria. Furthermore, we achieved a classification accuracy of 77.52% for the automatic identification of Dysphoria at a single-subject level.

Assessment of cognitive functions in individuals with post-traumatic symptoms after work-related accidents.

The investigation of cognitive functions in individuals who developed post-traumatic symptoms after occupational accidents has been overlooked in the relevant literature. The present study was aimed at assessing attention, memory and executive functions in individuals with post-traumatic symptoms after a workplace accident. Moreover, possible presence of emotional interference from trauma-related cues on attentional performance was evaluated. Results showed that injured workers exhibited deficits in perceptual-psychomotor skills, executive functions, attention and concentration abilities, and memory as compared with healthy controls. With regards to emotional interference on attention, injured workers were found to perform significantly worse than controls specifically when exposed to trauma-related pictures. Overall, these findings suggest that post-traumatic symptoms following a workplace accident are associated with several cognitive and emotional dysfunctions, that should be carefully evaluated to help reduce the frequency and the adverse consequences of occupational accidents.

Pain assessment in non-communicative patients: the Italian version of the Non-Communicative Patient's Pain Assessment Instrument (NOPPAIN).

BACKGROUND AND AIMS: Although pain in the elderly is a common and important problem, it is frequently underestimated and undertreated. Pain assessment in elderly people is often more difficult than in the general population, because of the occurrence of dementia and other cognitive impairments that may compromise the ability to communicate the presence and the intensity of pain to hospital staff. Recently, several observational tools have been developed in order to assess pain behaviors in non-communicative patients. The aim of the present study was to verify if the Italian version of the Non- Communicative Patient's Pain Assessment Instrument (NOPPAIN) could be used in a hospital setting. METHODS: Sixty severely demented patients (MMSE /=23, language test score >/=4) were selected on the basis of their cognitive status and language skills. NOPPAIN forms were filled in at the same time by two nursing staff members after patients' daily care activities; behavioral indicators of the affective state and communicative patients' reports of pain were also collected. RESULTS: Significant interrater agreement was found in the subscores of the four main sections of the NOPPAIN and also in the total score. In addition, in cognitively intact patients there was a moderate (about 0.50) but significant correlation between NOPPAIN ratings and pain self-reports. A positive correlation between pain scores and negative affective state scores was also found, especially in cognitively impaired patients. CONCLUSIONS: The preliminary data of the present study support the reliability and validity of the Italian version of the NOPPAIN, which appears to be an easy-to-use tool in the assessment of pain in hospitalized non-communicative patients.