Financial and recovery worry one year after traumatic injury: A prognostic, registry-based cohort study.

BACKGROUND: Levels of stress post-injury, especially after compensable injury, are known to be associated with worse long-term recovery. It is therefore important to identify how, and in whom, worry and stress manifest post-injury. This study aimed to identify demographic, injury, and compensation factors associated with worry about financial and recovery outcomes 12 months after traumatic injury. METHODS: Participants (n = 433) were recruited from the Victorian Orthopaedic Trauma Outcomes Registry and Victorian State Trauma Registry after admission to a major trauma hospital in Melbourne, Australia. Participants completed questionnaires about pain, compensation experience and psychological wellbeing as part of a registry-based observational study. RESULTS: Linear regressions showed that demographic and injury factors accounted for 11% and 13% of variance in financial and recovery worry, respectively. Specifically, lower education, discharge to inpatient rehabilitation, attributing fault to another and having a compensation claim predicted financial worry. Worry about recovery was only predicted by longer hospital stay and attributing fault to another. In all participants, financial and recovery worry were associated with worse pain (severity, interference, catastrophizing, kinesiophobia, self-efficacy), physical (disability, functioning) and psychological (anxiety, depression, PTSD, perceived injustice) outcomes 12 months post-injury. In participants who had transport (n = 135) or work (n = 22) injury compensation claims, both financial and recovery worry were associated with sustaining permanent impairments, and reporting negative compensation system experience 12 months post-injury. Financial worry 12 months post-injury was associated with not returning to work by 3-6 months post-injury, whereas recovery worry was associated with attributing fault to another, and higher healthcare use at 6-12 months post-injury. CONCLUSIONS: These findings highlight the important contribution of factors other than injury severity, to worry about finances and recovery post-injury. Having a compensation claim, failure to return to work and experiencing pain and psychological symptoms also contribute to elevated worry. As these factors explained less than half of the variance in worry, however, other factors not measured in this study must play a role. As worry may increase the risk of developing secondary mental health conditions, timely access to financial, rehabilitation and psychological supports should be provided to people who are not coping after injury.

Relationship between self-reported cognitive difficulties, objective neuropsychological test performance and psychological distress in chronic pain.

BACKGROUND: Persons with chronic pain often report problems with cognitive abilities, such as memory or attention. There is limited understanding of whether objective performance is consistent with subjective reports, and how psychological factors contribute. We aimed to investigate these relationships in a group of patients expressing cognitive concerns, and evaluate the utility of self-report tools for pain management settings. METHOD: Participants with chronic pain (n = 41) completed standardized neuropsychological tests, and self-report measures of cognitive functioning, pain, mood and sleep, as part of a broader study investigating cognitive performance in pain. RESULTS: Average neuropsychological test performance was subtly below normative means (within one standard deviation). Twenty-five percent of the sample scored substantially below age-adjusted norms on one or more objective tests. There were moderate-to-large associations between objective performance (e.g. Trail-Making B) and subjective cognitive complaints (e.g. Everyday Memory Questionnaire - Revised), controlling for age and education level. This was moderated by anxiety, such that subjective-objective relationships were particularly strong in those with higher anxiety. Poorer test performance was associated with higher pain intensity and catastrophizing. Subjective-objective cognition relationships remained after controlling for catastrophizing. CONCLUSION: Patients' self-reported cognitive concerns concurred with objectively measured performance, independent of age, education and catastrophizing. Moreover, those with severe anxiety were more accurate in predicting their cognitive performance. The findings highlight some interesting cognition-mood relationships, and suggest that easy-to-administer questionnaires, such as the Everyday Memory Questionnaire - Revised and the Behavior Rating Inventory of Executive Function - Adult Version, may be useful to capture cognitive concerns in clinical settings. SIGNIFICANCE: Cognitive concerns in chronic pain reflected objective neurocognitive performance. This was moderated by anxiety, such that self-reported cognition was more consistent with objective performance in those with high anxiety. Our findings suggest that reported cognitive concerns should be heeded, and self-report measures may be used clinically to facilitate dialogue about cognitive functioning.

Location, location, location: Variation in sensitivity to pain across the body.

BACKGROUND: There is evidence that sensitivity to noxious stimuli differs between the sexes and across the body, but few studies have investigated differences in the perception and experience of acute pain stimuli across the body in healthy individuals. METHODS: We recruited 52 healthy participants, aged 18-36 (50% men) and administered 39, 42 and 45 °C stimuli at four body sites bilaterally to examine differences in the experience of pain intensity and unpleasantness between body sites via an 11-point numerical rating scale. RESULTS: Noxious and innocuous thermal heat stimuli were perceived as significantly more intense when delivered to the wrist (M = 3.98, SD = 1.93) and back (M = 4.07, SD = 1.98) compared to the shoulder (M = 3.45, SD = 1.91) and leg (M = 3.46, SD = 1.87). Pain unpleasantness ratings yielded similar findings; stimuli were perceived as more unpleasant when administered to the wrist (M = 2.83, SD = 1.93) and lower back (M = 3.04, SD = 2.11) compared to the shoulder (M = 2.63, SD = 1.85) and leg (M = 2.26, SD = 1.82). CONCLUSIONS: These findings suggest that painful thermal stimuli delivered to the wrist and back are perceived as more intense and unpleasant compared with other body sites in healthy persons. These differences may be due to variations in receptor density, or the relative importance of these sites for daily living and survival. SIGNIFICANCE: Moreover, these insights are helpful for the design of studies investigating pain experience in healthy persons in experimental or clinical settings. WHAT DOES THIS STUDY ADD?: We tested sensitivity to acute suprathreshold thermal stimulations across a range of body sites to investigate for potential variability. We found significant differences in the perceived intensity and unpleasantness of noxious and innocuous thermal stimuli at the wrist and lower back, compared with the shoulder and leg. These results suggest that pain experience is driven by receptor density or the relative functional importance of these sites.

Preliminary evidence of an effect of cerebellar volume on postural sway in FMR1 premutation males.

Recent evidence suggests that early changes in postural control may be discernible among females with premutation expansions (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene at risk of developing fragile X-associated tremor ataxia syndrome (FXTAS). Cerebellar dysfunction is well described in males and females with FXTAS, yet the interrelationships between cerebellar volume, CGG repeat length, FMR1 messenger RNA (mRNA) levels and changes in postural control remain unknown. This study examined postural sway during standing in a cohort of 22 males with the FMR1 premutation (ages 26-80) and 24 matched controls (ages 26-77). The influence of cerebellar volume, CGG repeat length and FMR1 mRNA levels on postural sway was explored using multiple linear regression. The results provide preliminary evidence that increasing CGG repeat length and decreasing cerebellar volume were associated with greater postural sway among premutation males. The relationship between CGG repeat length and postural sway was mediated by a negative association between CGG repeat size and cerebellar volume. While FMR1 mRNA levels were significantly elevated in the premutation group and correlated with CGG repeat length, FMR1 mRNA levels were not significantly associated with postural sway scores. These findings show for the first time that greater postural sway among males with the FMR1 premutation may reflect CGG repeat-mediated disruption in vulnerable cerebellar circuits implicated in postural control. However, longitudinal studies in larger samples are required to confirm whether the relationships between cerebellar volume, CGG repeat length and postural sway indicate greater risk for neurological decline.

Affective, sensory and empathic sharing of another's pain: The Empathy for Pain Scale.

BACKGROUND: Through two studies, we introduce and validate the Empathy for Pain Scale (EPS), which characterizes the phenomenology of empathy for pain, including the vicarious experience of pain when seeing others in pain. METHODS: In study 1, 406 individuals completed the EPS and Interpersonal Reactivity Index (IRI). In the EPS, four painful scenarios (witnessing surgery, patient recovering from surgery, assault and accidental injury) were rated for 12 emotional, empathic and sensory responses. In study 2, 59 participants completed the same questionnaires and then watched and rated videos of sporting injuries. RESULTS: In study 1, we identified three factors of the EPS with principal component analysis, which were validated with confirmatory factor analysis: affective distress; vicarious pain; and empathic concern. The EPS demonstrated good psychometric properties, re-test reliability (n = 105) and concurrent validity. In study 2, we validated the EPS against empathic reactions to the pain of others as displayed in video clips depicting sporting injuries and showed that the scale has unique utility to characterize empathic reactions to pain above general trait empathy measures. Both studies showed that the affective distress and empathic concern subscales of the EPS correlated with measures of cognitive and affective empathy from the IRI, whereas the vicarious pain subscale was only correlated with the personal distress IRI subscale. CONCLUSIONS: The EPS is a psychometrically sound new scale that characterizes empathy for pain and vicarious pain. The EPS offers valuable insight to the phenomenological profile of the affective, empathic and sensory dimensions of empathy for pain.

Symbolic sequence learning is associated with cognitive-affective profiles in female FMR1 premutation carriers.

This study examines implicit sequence learning impairments that may indicate at-risk cerebellar profiles proposed to underlie some aspects of subtle cognitive and affective dysfunctions found among female fragile X mental retardation 1 (FMR1) premutation (PM)-carriers. A total of 34 female PM-carriers and 33 age- and intelligence-matched controls completed an implicit symbolically primed serial reaction time task (SRTT) previously shown to be sensitive to cerebellar involvement. Implicit learning scores indicated a preservation of learning in both groups; however, PM-carriers demonstrated poorer learning through significantly elevated response latencies overall and at each specific block within the symbolic SRTT. Group comparisons also revealed a core deficit in response inhibition, alongside elevated inattentive symptoms in female PM-carriers. Finally, strong and significant associations were observed between poor symbolic SRTT performance and executive, visuospatial and affective deficits in the PM-carrier group. These associations remained strong even after controlling motor speed, and were not observed in age- and intelligence quotient-matched participants. The findings implicate cerebellar non-motor networks subserving the implicit sequencing of responses in cognitive-affective phenotypes previously observed in female PM-carriers. We contend that symbolic SRTT performance may offer clinical utility in future pharmaceutical interventions in female PM-carriers.

Emotion perception and electrophysiological correlates in Huntington's disease.

OBJECTIVE: This study aimed to characterise, emotion perception deficits in symptomatic Huntington's disease (HD) via the use of event-related potentials (ERPs). METHODS: ERP data were recorded during a computerised facial expression task in 11 HD participants and 11 matched controls. Expression (scrambled, neutral, happy, angry, disgust) classification accuracy and intensity were assessed. Relationships between ERP indices and clinical disease characteristics were also examined. RESULTS: Accuracy was significantly lower for HD relative to controls, due to reduced performance for neutral, angry and disgust (but not happy) faces. Intensity ratings did not differ between groups. HD participants displayed significantly reduced visual processing amplitudes extending across pre-face (P100) and face-specific (N170) processing periods, whereas subsequent emotion processing amplitudes (N250) were similar across groups. Face-specific and emotion-specific derivations of the N170 and N250 ('neutral minus scrambled' and 'each emotion minus neutral', respectively) did not differ between groups. CONCLUSIONS: Our data suggest that the facial emotion recognition performance deficits in HD are primarily related to neural degeneration underlying 'generalised' visual processing, rather than face or emotional specific processing. SIGNIFICANCE: ERPs are a useful tool to separate functionally discreet impairments in HD, and provide an important avenue for biomarker application that could more-selectively track disease progression.

Prefrontal activity in Huntington's disease reflects cognitive and neuropsychiatric disturbances: the IMAGE-HD study.

Functional integrity of prefrontal cortico-striatal circuits underlying executive functioning may be compromised by basal ganglia degeneration during Huntington's disease (HD). This study investigated challenged inhibitory attentional control with a shifting response-set (SRS) task whilst assessing neural response via functional magnetic resonance imaging (fMRI) in 35 healthy controls, 35 matched pre-symptomatic (pre-HD) and 30 symptomatic (symp-HD) participants. A ≥70% performance accuracy threshold allowed confident identification of neural activity associated with SRS performance in a sub-set of 33 healthy controls, 32 pre-HD and 20 symp-HD participants. SRS activated dorsolateral prefrontal and dorsal anterior cingulate cortices, premotor, parietal, and basal ganglia regions and deactivated subgenual anterior cingulate cortex. Symp-HD participants showed greater prefrontal functional responses relative to controls and pre-HD, including larger activations and larger deactivations in response to cognitive challenge, consistent with compensatory neural recruitment. We then investigated associations between prefrontal BOLD responses, SRS performance accuracy and neuropsychiatric disturbance in all participants, including those below SRS performance accuracy threshold. We observed that reduced prefrontal responsivity in symp-HD was associated with reduced accuracy in SRS performance, and with increased neuropsychiatric disturbance within domains including executive dysfunction, pathological impulses, disinhibition, and depression. These findings demonstrate prefrontal response during inhibitory attentional control usefully characterises cognitive and neuropsychiatric status in symp-HD. The functional integrity of compensatory prefrontal responses may provide a useful marker for treatments which aim to sustain cognitive function and delay executive and neuropsychiatric disturbance.

Automated differentiation of pre-diagnosis Huntington's disease from healthy control individuals based on quadratic discriminant analysis of the basal ganglia: the IMAGE-HD study.

We investigated two measures of neural integrity, T1-weighted volumetric measures and diffusion tensor imaging (DTI), and explored their combined potential to differentiate pre-diagnosis Huntington's disease (pre-HD) individuals from healthy controls. We applied quadratic discriminant analysis (QDA) to discriminate pre-HD individuals from controls and we utilised feature selection and dimension reduction to increase the robustness of the discrimination method. Thirty six symptomatic HD (symp-HD), 35 pre-HD, and 36 control individuals participated as part of the IMAGE-HD study and underwent T1-weighted MRI, and DTI using a Siemens 3 Tesla scanner. Volume and DTI measures [mean diffusivity (MD) and fractional anisotropy (FA)] were calculated for each group within five regions of interest (ROI; caudate, putamen, pallidum, accumbens and thalamus). QDA was then performed in a stepwise manner to differentiate pre-HD individuals from controls, based initially on unimodal analysis of motor or neurocognitive measures, or on volume, MD or FA measures from within the caudate, pallidum and putamen. We then tested for potential improvements to this model, by examining multi-modal MRI classifications (volume, FA and MD), and also included motor and neurocognitive measures, and additional brain regions (i.e., accumbens and thalamus). Volume, MD and FA differed across the three groups, with pre-HD characterised by significant volumetric reductions and increased FA within caudate, putamen and pallidum, relative to controls. The QDA results demonstrated that the differentiation of pre-HD from controls was highly accurate when both volumetric and diffusion data sets from basal ganglia (BG) regions were used. The highest discriminative accuracy however was achieved in a multi-modality approach and when including all available measures: motor and neurocognitive scores and multi-modal MRI measures from the BG, accumbens and thalamus. Our QDA findings provide evidence that combined multi-modal imaging measures can accurately classify individuals up to 15 years prior to onset when therapeutic intervention is likely to have maximal effects in slowing the trajectory of disease development.

A functional MRI study of motor dysfunction in Friedreich's ataxia.

Friedreich's ataxia (FRDA) is the most common form of hereditary ataxia. In addition to proximal spinal cord and brain stem atrophy, mild to moderate atrophy of the cerebellum has been reported in advanced FRDA. The aim of this study was to examine dysfunction in motor-related areas involved in the execution of finger tapping tasks in individuals with FRDA, and to investigate functional re-organization of cortico-cerebellar, cortico-striatal and parieto-frontal loops as a result of the cerebellar pathology. Thirteen right-handed individuals with FRDA and fourteen right-handed controls participated. Functional MRI images were acquired during four different finger tapping tasks consisting of visually cued regular and irregular single finger tapping tasks, a self-paced regular finger tapping task, and a visually cued multi-finger tapping task. Both groups showed significant activation of the motor-related network including the pre-central cortex and supplementary motor area bilaterally; the left primary motor cortex, somatosensory cortex and putamen; and the right cerebellum. During the visually cued regular finger tapping task, the right hemisphere of the cerebellar cortex, bilateral supplementary motor areas and right inferior parietal cortex showed higher activation in the healthy control group, while in individuals with FRDA the left premotor cortex, left somatosensory cortex and left inferior parietal cortex were more active. In addition, during the visually cued irregular finger tapping task, the right middle temporal gyrus in the control group and the right superior parietal lobule and left superior and middle temporal gyri in the individuals with FRDA showed higher activation. During visually cued multi-finger tapping task, the control group showed higher activation in the bilateral middle frontal gyri, bilateral somatosensory cortices, bilateral inferior parietal lobules, left premotor cortex, left supplementary area, right superior frontal gyrus and right cerebellum, while individuals with FRDA showed increased activity in the left inferior parietal lobule, left primary motor cortex, left middle occipital gyrus, right somatosensory cortex and the left cerebellum. Only the right crus I/II of the cerebellum showed higher activation in individuals with FRDA during the self-paced regular finger tapping task, whereas wide-spread regions including the left superior frontal gyrus, left central opercular cortex, left somatosensory cortex, left putamen, right cerebellum, bilateral primary motor cortices, bilateral inferior parietal lobules and the left insula were more active in the control group. Although the pattern of the BOLD signal from the putamen was different during the self-paced regular finger tapping task to the other tasks in controls, in individuals with FRDA there was no distinction of the signal between the tasks suggesting that primary cerebellar pathology may cause secondary basal ganglia dysregulation. While individuals with FRDA tapped at a slightly lower rate (0.59Hz) compared with controls (0.74Hz) they showed significantly decreased activity of the SMA and the inferior parietal lobule, which may suggest disruption to the fronto-parietal connections. These findings suggest that the motor impairments in individuals with FRDA result from dysfunction extending beyond the spinal cord and cerebellum to include sub-cortical and cortical brain regions.

Decreased functional brain activation in Friedreich ataxia using the Simon effect task.

The present study applied the Simon effect task to examine the pattern of functional brain reorganization in individuals with Friedreich ataxia (FRDA), using functional magnetic resonance imaging (fMRI). Thirteen individuals with FRDA and 14 age and sex matched controls participated, and were required to respond to either congruent or incongruent arrow stimuli, presented either to the left or right of a screen, via laterally-located button press responses. Although the Simon effect (incongruent minus congruent stimuli) showed common regions of activation in both groups, including the superior and middle prefrontal cortices, insulae, superior and inferior parietal lobules (LPs, LPi), occipital cortex and cerebellum, there was reduced functional activation across a range of brain regions (cortical, subcortical and cerebellar) in individuals with FRDA. The greater Simon effect behaviourally in individuals with FRDA, compared with controls, together with concomitant reductions in functional brain activation and reduced functional connectivity between cortical and sub-cortical regions, implies a likely disruption of cortico-cerebellar loops and ineffective engagement of cognitive/attention regions required for response suppression.

The Fitts task reveals impairments in planning and online control of movement in Friedreich ataxia: reduced cerebellar-cortico connectivity?

Friedreich ataxia (FRDA) is the most common of the inherited ataxias. We have suggested that people with FRDA may have impairment in cognitive and/or psychomotor capacity either due to disturbance of projections of the cerebellum to the cortex, direct cortical pathology or perhaps both. To further explore this possibility, we used a movement task incorporating Fitts' Law, a robust description of the relationship between movement time and accuracy in goal-directed aiming movements. By manipulating task difficulty, according to target size and distance, we were able to quantify processes related to motor planning in 10 individuals with FRDA and 10 matched control participants. Compared to control participants, people with FRDA were significantly disadvantaged in terms of movement time to targets with an increasing index of difficulty. Successful completion of this task requires both preplanning of movement and online error detection and correction. The cerebellum and its connections to the frontal cortex via cerebro-ponto-cerebello-thalamo-cerebral loops are fundamental to both processes. These results lend further support to our contention that in FRDA these loops are impaired, reflecting a failure to access prefrontal/anterior regions necessary for effective management of preplanning of movement and online error correction.

Impaired inhibition of prepotent motor tendencies in Friedreich ataxia demonstrated by the Simon interference task.

Friedreich ataxia (FRDA) is the most common of the genetically inherited ataxias. We recently demonstrated that people with FRDA have impairment in motor planning - most likely because of pathology affecting the cerebral cortex and/or cerebello-cortical projections. We used the Simon interference task to examine how effective 13 individuals with FRDA were at inhibiting inappropriate automatic responses associated with stimulus-response incompatibility in comparison with control participants. Participants had to respond to arrow targets according to two features which were either congruent or incongruent. We found that individuals with FRDA were differentially affected in reaction time to incongruent, compared with congruent stimuli, when compared with control participants. There was a significant negative correlation between age of onset and the incongruency effect, suggesting an impact of FRDA on the developmental unfolding of motor cognition, independent of the effect of disease duration. Future neuroimaging studies will be required to establish whether this dysfunction is due to cerebellar impairment disrupting cerebro-ponto-cerebello-thalamo-cerebral loops (and thus cortical function), direct primary cortical pathology, or a possible combination of the two.

Functional connectivity of the prefrontal cortex in Huntington's disease.

BACKGROUND: Huntington's disease is a progressive neurodegenerative disorder that results in deterioration and atrophy of various brain regions. AIM: To assess the functional connectivity between prefrontal brain regions in patients with Huntington's disease, compared with normal controls, using functional magnetic resonance imaging. PATIENTS AND METHODS: 20 patients with Huntington's disease and 17 matched controls performed a Simon task that is known to activate lateral prefrontal and anterior cingulate cortical regions. The functional connectivity was hypothesised to be impaired in patients with Huntington's disease between prefrontal regions of interest, selected from both hemispheres, in the anterior cingulate and dorsal lateral prefrontal cortex. RESULTS: Controls showed a dynamic increase in interhemispheric functional connectivity during task performance, compared with the baseline state; patients with Huntington's disease, however, showed no such increase in prefrontal connectivity. Overall, patients with Huntington's disease showed significantly impaired functional connectivity between anterior cingulate and lateral prefrontal regions in both hemispheres compared with controls. Furthermore, poor task performance was predicted by reduced connectivity in patients with Huntington's disease between the left anterior cingulate and prefrontal regions. CONCLUSIONS: This finding represents a loss of synchrony in activity between prefrontal regions in patients with Huntington's disease when engaged in the task, which predicted poor task performance. Results show that functional interactions between critical prefrontal regions, necessary for cognitive performance, are compromised in Huntington's disease. It is speculated whether significantly greater levels of activation in patients with Huntington's disease (compared with controls) observed in several brain regions partially compensate for the otherwise compromised interactions between cortical regions.

Negative symptoms: A review of schizophrenia, melancholic depression and Parkinson's disease.

Negative symptoms generally refer to a reduction in normal functioning. In schizophrenia they encompass apathy, anhedonia, flat affect, avolition, social withdrawal and, on some accounts, psychomotor retardation. Negative symptoms have been identified in other psychiatric disorders, including melancholic depression, and also in neurological disorders, such Parkinson's disease. Achieving a better understanding of negative symptoms constitutes a priority in mental health. Primarily, negative symptoms represent an unrelenting, intractable and disabling feature for patients, often amounting to a severe burden on families, carers and the patients themselves. Identifying and understanding subgroups within disorders may also contribute to the clinical care and scientific understanding of the pathophysiology of these disorders. The purpose of this paper is to review the current literature on negative symptoms in schizophrenia and explore the idea that negative symptoms may play an important role not only in other psychiatric disorders such as melancholic depression, but also in neurological disorders, such as Parkinson's disease. In each disorder negative symptoms manifest with similar motor and cognitive impairments and are associated with comparable neuropathological and biochemical findings, possibly reflecting analogous impairments in the functioning of frontostriatal-limbic circuits.

Self-paced saccades and saccades to oddball targets in Parkinson's disease.

Patients with Parkinson's disease (PD) manifest difficulty in initiation and execution of movements, particularly when movements are sequential, simultaneous or repetitive. Eye movements are particularly effective in evaluating motor impairments. We utilized a series of saccadic eye movement paradigms to explore the ability of 13 patients with mild-moderate PD and 13 age-matched healthy controls to self-pace saccades between two continuously illuminated targets, before and after an externally cued tracking period, and respond to unexpected changes in task demand. The latter was explored by measuring saccadic responses to unexpected "oddball" targets that appeared during a well-learned reciprocating sequence of saccades, in either the opposite direction to that expected or at twice the anticipated extent. Results indicated that all participants demonstrated a marked increase in saccade amplitudes from the externally cued saccade tracking to the self-paced saccades. Unexpectedly, this difference was magnified in PD patients. Self-paced saccades before externally cueing were also more frequent than requested in the PD group, but timing improved following external cueing. The second key finding was that while patients were able to respond to unexpected changes in target amplitude, performance was more variable (in terms of latency and accuracy) when responding to unexpected changes in target direction. Hence, beneficial effects of external cueing on the timing of self-paced saccades may be mediated through cortical regions, placing less emphasis on striatal regions known to be compromised in PD. Additionally, responding to changes in saccade direction (but not amplitude) may rely on basal ganglia circuitry.

Ocular motor differences between melancholic and non-melancholic depression.

BACKGROUND: Major depressive disorder may be a heterogeneous disorder, yet melancholic depression is the most consistently described subtype, regarded as qualitatively different to non-melancholic depression in terms of cognitive and motor impairments. Eye movement studies in depression are infrequent and findings are inconclusive. METHODS: This study employed a battery of saccadic eye movement tasks to explore reflexive saccades, as well as higher order cognitive aspects of saccades including inhibitory control and spatial working memory. Nineteen patients with major depressive disorder (9 melancholic; 10 non-melancholic) and 15 healthy controls participated. RESULTS: Differences were revealed between melancholic and non-melancholic patients. Melancholia was associated with longer latencies, difficulty increasing peak velocities as target amplitudes increased, and hypometric primary saccades during the predictable protocol. In contrast, the non-melancholic depression group performed similarly to controls on most tasks, but saccadic peak velocity was increased for reflexive saccades at larger amplitudes. LIMITATIONS: Most patients were taking antidepressant medication. CONCLUSIONS: The latency increases, reduced peak velocity and primary saccade hypometria with more severe melancholia may be explained by functional changes in the fronto-striatal-collicular networks, related to dopamine dysfunction. In contrast, the serotonergic system plays a greater role in non-melancholic symptoms and this may underpin the observed increases in saccadic peak velocity. These findings provide neurophysiological support for functional differences between depression subgroups that are consistent with previous motor and cognitive findings.

The semantic Simon effect in Tourette's syndrome and obsessive-compulsive disorder.

Core symptoms of Tourette's syndrome (TS) and obsessive-compulsive disorder (OCD) may be attributed to an impairment in inhibitory control. Neuropsychological studies have addressed inhibition in both disorders, but findings have been inconsistent. The aim of this study was to examine cognitive inhibition, using a semantic Simon effect paradigm, in patients with TS and OCD. Furthermore, to address comorbidity a group of TS+OCD patients was also examined. Results indicated that patients with TS and OCD were affected by the inhibitory components of the task. TS groups performed similarly to controls on simple and choice RT tasks, but were particularly compromised as increasingly complex inhibitory demands were imposed. OCD patients were slower and committed more errors than controls, especially in the more cognitively demanding conditions, and were particularly disadvantaged by incongruent stimulus-response compatibilities. Findings implicate possible fronto-striatal dysfunction, are consistent with previously reported inhibitory deficits in TS and OCD, and support the theory that comorbid TS+OCD is more closely linked to pure TS than OCD.