Functional near-infrared spectroscopy (fNIRS) is an emerging functional neuroimaging technology offering a relatively non-invasive, safe, portable, and low-cost method of indirect and direct monitoring of brain activity. Most exciting is its potential to allow more ecologically valid investigations that can translate laboratory work into more realistic everyday settings and clinical environments. Our aim is to acquaint clinicians and researchers with the unique and beneficial characteristics of fNIRS by reviewing its relative merits and limitations vis-à-vis other brain-imaging technologies such as functional magnetic resonance imaging (fMRI). We review cross-validation work between fMRI and fNIRS, and discuss possible reservations about its deployment in clinical research and practice. Finally, because there is no comprehensive review of applications of fNIRS to brain disorders, we also review findings from the few studies utilizing fNIRS to investigate neurocognitive processes associated with neurological (Alzheimer's disease, Parkinson's disease, epilepsy, traumatic brain injury) and psychiatric disorders (schizophrenia, mood disorders, anxiety disorders).

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Introduction Emotion perception (EP) is impaired in schizophrenia, is stable across clinical state, resistant to antipsychotic treatment and linked to symptom severity. Given its pervasive nature, there is a need to quantitatively examine whether this dysfunction impacts functional outcomes. We used a meta-analytic strategy to combine results from several studies and examine synthesized effect sizes. Methods A Meta-analysis Of Observational Studies in Epidemiology standard was used to extract data following a PubMed and PsychInfo search. Studies reporting correlations between measures of EP and functional outcomes in schizophrenia spectrum disorders were selected. The impact of potential methodological (task type), demographic (sex, age, race, education, marital status) and clinical (age of onset, duration of illness, setting, symptoms, anti-psychotic medication) moderators on effect sizes were examined. Results Twenty-five studies met inclusion criteria and included 1306 patients who were 37 years old, with 12 years of education, 64% male and 63% Caucasian. There was a significant relationship between EP and functional outcomes in individuals with schizophrenia or schizoaffective disorder, with effect sizes in the medium range. Medium to large range positive correlations were observed between emotion identification and functional outcome domains involving social problem solving, social skills and community functioning. Significant moderators included task type (emotion identification tasks), sex (% male in sample), race (% Caucasian in sample) and clinical symptoms (negative and positive). Conclusions Emotion identification deficits are associated with functional impairments in schizophrenia and moderated by sex, race and symptoms. This has implications for treatment efforts to improve outcomes.

Objective: Cognitive deficits are among the most reliable predictors of functional impairment in schizophrenia and a particular concern for older individuals with schizophrenia. Previous reviews have focused on the nature and course of cognitive impairments in younger cohorts, but a quantitative meta-analysis in older patients is pending. Method: A previously used search strategy identified studies assessing performance on tests of global cognition and specific neuropsychological domains in older patients with schizophrenia and age-matched comparison groups. Both crosssectional and longitudinal studies were included. Potential methodological, demographic, and clinical moderators were analyzed. Results: Twenty-nine cross-sectional (2110 patients, 1738 comparison subjects) and 14 longitudinal (954 patients) studies met inclusion criteria. Patients were approximately 65 years old, with 11 years of education, 53% male and 79% Caucasian. Longitudinal analysis (range 1-6 years) revealed homogeneity with small effect sizes (d 5 20.097) being observed. Cross-sectional analyses revealed large and heterogeneous deficits in global cognition (d 5 21.19) and on specific neuropsychological tests (d 5 20.7 to 21.14). Moderator analysis revealed a significant role for demographic (age, sex, education, race) and clinical factors (diagnosis, inpatient status, age of onset, duration of illness, positive and negative symptomology). Medication status (medicated vs nonmedicated) and chlorpromazine equivalents were inconsequential, albeit underrepresented. Conclusions: Large and generalized cognitive deficits in older individuals with schizophrenia represent a robust finding paralleling impairments across the life span, but these deficits do not decline over a 1-6 year period. The importance of considering demographic and clinical moderators in cross-sectional analyses is highlighted.