Affective Prosody and Its Impact on the Neurology of Language, Depression, Memory and Emotions

Based on the seminal publications of Paul Broca and Carl Wernicke who established that aphasic syndromes (disorders of the verbal-linguistic aspects of communication) were predominantly the result of focal left-hemisphere lesions, "language" is traditionally viewed as a lateralized function of the left hemisphere. This, in turn, has diminished and delayed the acceptance that the right hemisphere also has a vital role in language, specifically in modulating affective prosody, which is essential for communication competency and psychosocial well-being. Focal lesions of the right hemisphere may result in disorders of affective prosody (aprosodic syndromes) that are functionally and anatomically analogous to the aphasic syndromes that occur following focal left-hemisphere lesions. This paper will review the deductive research published over the last four decades that has elucidated the neurology of affective prosody which, in turn, has led to a more complete and nuanced understanding of the neurology of language, depression, emotions and memory. In addition, the paper will also present the serendipitous clinical observations (inductive research) and fortuitous inter-disciplinary collaborations that were crucial in guiding and developing the deductive research processes that culminated in the concept that primary emotions and related display behaviors are a lateralized function of the right hemisphere and social emotions, and related display behaviors are a lateralized function of the left hemisphere.

White Matter Network Disruption Is Associated With Melancholic Features in Major Depressive Disorder

BACKGROUND

The efficacy and prognosis of major depressive disorder (MDD) are limited by its heterogeneity. MDD with melancholic features is an important subtype of MDD. The present study aimed to reveal the white matter (WM) network changes in melancholic depression.

MATERIALS AND METHODS

Twenty-three first-onset, untreated melancholic MDD, 59 non-melancholic MDD patients and 63 health controls underwent diffusion tensor imaging (DTI) scans. WM network analysis based on graph theory and support vector machine (SVM) were used for image data analysis.

RESULTS

Compared with HC, small-worldness was reduced and abnormal node attributes were in the right orbital inferior frontal gyrus, left orbital superior frontal gyrus, right caudate nucleus, right orbital superior frontal gyrus, right orbital middle frontal gyrus, left rectus gyrus, and left median cingulate and paracingulate gyrus of MDD patients. Compared with non-melancholic MDD, small-worldness was reduced and abnormal node attributes were in right orbital inferior frontal gyrus, left orbital superior frontal gyrus and right caudate nucleus of melancholic MDD. For correlation analysis, the 7th item score of the HRSD-17 (work and interest) was positively associated with increased node betweenness centrality (aBC) values in right orbital inferior frontal gyrus, while negatively associated with the decreased aBC in left orbital superior frontal gyrus. SVM analysis results showed that abnormal aBC in right orbital inferior frontal gyrus and left orbital superior frontal gyrus showed the highest accuracy of 81.0% (69/83), the sensitivity of 66.3%, and specificity of 85.2% for discriminating MDD patients with or without melancholic features.

CONCLUSION

There is a significant difference in WM network changes between MDD patients with and without melancholic features.

Differentiating Melancholic and Non-melancholic Major Depressive Disorder Using Fractional Amplitude of Low-Frequency Fluctuations

BACKGROUND

Melancholic major depressive disorder (MDD) is a network-based brain disorder. However, whether or not network-based changes can be applied to differentiate melancholic (MEL) from non-melancholic (NMEL) MDD remains unclear.

METHODS

Thirty-one MEL patients, 28 NMEL patients, and 32 matched healthy controls (HCs) were scanned using resting-state functional magnetic resonance imaging. Patients were assessed by the Chinese version of Snaith-Hamilton Pleasure Scale (SHAPS-C) and Temporal Experience of Pleasure Scale (TEPS). Fractional amplitude of low-frequency fluctuations (fALFF) and correlation analysis were used to analyze the data.

RESULTS

Compared with HCs, the MEL group had significantly higher fALFF values in the bilateral inferior frontal gyrus and right supplementary motor area (SMA) and significantly lower fALFF values in the right inferior occipital gyrus (IOG), right middle temporal gyrus (MTG)/left IOG, and bilateral superior occipital gyrus (SOG)/MTG. On the other hand, the NMEL group showed significantly higher fALFF values in the bilateral SMA and significantly lower fALFF values in the bilateral posterior cingulate cortex/precuneus relative to HCs. Compared with the NMEL group, the MEL group showed significantly lower fALFF values in the left anterior cingulate cortex (ACC). A correlation was found between the fALFF values of the right SMA and the SHAPS-C in the MEL group. In addition, correlations were observed between the fALFF values of the left ACC and the TEPS contextual consummatory and total scores in all patients.

CONCLUSION

Our study uncovered that MDD exhibited altered brain activity in extensive brain networks, including the default-mode network, frontal-striatal network, reward system, and frontal-limbic network. Decreased fALFF in the left ACC might be applied to differentiate the two subtypes of MDD.

Disrupted Regional Homogeneity in Melancholic and Non-melancholic Major Depressive Disorder at Rest

Background: Melancholic depression has been viewed as one severe subtype of major depressive disorder (MDD). However, it is unclear whether melancholic depression has distinct changes in brain imaging. We aimed to explore specific or distinctive alterations in melancholic MDD and whether the alterations could be used to separate melancholic MDD from non-melancholic MDD or healthy controls. Materials and Methods: Thirty-one outpatients with melancholic MDD and thirty-three outpatients with non-melancholic MDD and thirty-two age- and gender-matched healthy controls were recruited. All participants were scanned by resting-state functional magnetic resonance imaging (fMRI). Imaging data were analyzed with the regional homogeneity (ReHo) and support vector machine (SVM) methods. Results: Melancholic MDD patients exhibited lower ReHo in the right superior occipital gyrus/middle occipital gyrus than non-melancholic MDD patients and healthy controls. Merely for non-melancholic MDD patients, decreased ReHo in the right middle frontal gyrus was negatively correlated with the total HRSD-17 scores. SVM analysis results showed that a combination of abnormal ReHo in the right fusiform gyrus/cerebellum Crus I and the right superior occipital gyrus/middle occipital gyrus exhibited the highest accuracy of 83.05% (49/59), with a sensitivity of 90.32% (28/31), and a specificity of 75.00% (21/28) for discriminating patients with melancholic MDD from patients with non-melancholic MDD. And a combination of abnormal ReHo in the right fusiform gyrus/cerebellum VI and left postcentral gyrus/precentral gyrus exhibited the highest accuracy of 98.41% (62/63), with a sensitivity of 96.77% (30/31), and a specificity of 100.00%(32/32) for separating patients with melancholic MDD from healthy controls. Conclusion: Our findings showed the distinctive ReHo pattern in patients with melancholic MDD and found brain area that may be associated with the pathophysiology of non-melancholic MDD. Potential imaging markers for discriminating melancholic MDD from non-melancholic MDD or healthy controls were reported.

Characterological depression in patients with narcissistic personality disorder

Background: Depressive symptoms often occur in patients with personality disorders. Along the lines of the precious concepts of reactive and melancholic forms of depression, two different patterns of depressive symptoms can be identified. Reactive forms of depression is considered to be related to dysfunction of emotional regulation and social functioning, and to personality disorders. This study aimed at exploring the pattern of depressive symptoms in patients with Narcissistic Personality Disorder (NPD) compared to a group of depressed patients without Personality Disorder (PD). The Newcastle Diagnostic Depression Scale (NDDS) is a clinical instrument designed to differentiate reactive depression from melancholic depression. Method: The study investigated patterns of depressive symptoms in 117 out-patients, divided into two groups. One group containing 56 patients with depressive symptoms by no PD and the other group comprised of 61 patients with depressive symptoms and NPD. The participants were interviewed using the Newcastle Diagnostic Depression Scale. Results: There was a significant difference between the groups, as the NPD group suffered from reactive forms of depression. The NPD group showed a pattern of depressive symptoms characterized by fluctuation of the depressive state, without time demarcation of depressive episode, ruminations preoccupied with hostility and accusatory feelings towards other, but not self-accusatory feelings, fluctuation suicidal ideation triggered by external events accompanied by parasuicidal behavior, lack of neuro-vegetative symptoms such as insomnia with early wakening, loss of appetite and weight loss. The No PD group showed the opposite pattern. Conclusion: Based on these results NDDS is considered to be an applicable instrument for identifying personality pathology in patients with depressive symptoms, by recognizing the specific pattern. This is thought to be important for adequate treatment planning.

Treatment options for real-life patients

Our current models of depression and clinical trials data provide inadequate and relatively meaningless clinical information. They do not take into account the multiple phenotypes of depression and often do not include patients with "real-life" clinical depression. Psychiatry is called an evidence-based specialty, and this is supported by the wealth of evidence provided by the antidepressant drug trials. However, if the evidence demonstrated by these trials is not accurate, then psychiatry may fail to provide satisfactory treatment for patients with depression. Trial data commonly show the effect of antidepressant treatment to be indistinguishable from placebo. On first examination it could be said that antidepressant drugs act mainly as placebos, or, even worse, that antidepressant drugs are no better than placebos in effect. However, this view is at odds with the observations of clinicians in everyday practice, and the impact of this perception is worrying, with the pharmaceutical companies, patients and practitioners all being adversely affected. Randomised controlled trials (RCTs) provide limited data about the true effectiveness of an antidepressant. However, such RCTs are required by regulatory authorities for drug approval. Antidepressant effects in "real-life" depression need further investigation. When efficacy data for drug and non-drug treatments for major depression are compared, there are very few differences. This lack of differentiation across treatments allows every therapy to be perceived as efficacious, but also non-specific. This leads to patients being fitted to their therapist's preferred treatment, and not vice versa. This "all roads lead to rome" model is contrary to the rest of medicine, where differential treatment effects are to be expected. Why, therefore, is there confusion? A dimensional model for depression homogenises the multiple underlying subtypes of depression. This leads to treatments being tested as having universal application instead of targeting the specific depressive subtypes. This largely underpins the lack of specificity in RCT evidence. These trials involve patients who bear little resemblance to those who clinicians see in everyday practice. These trials also select and favour natural and rapid responders. Therefore the failure to differentiate between drug and placebo is unsurprising in the RCTs. Our spectrum model seeks to identify clinically meaningful expressions of depression, allowing drugs to be targeted to separate depressive conditions and their underlying cause. This allows a rational model for prevention and long-term management. For example, when treating depression associated with anxiety, selective serotonin reuptake inhibitors (SSRIs) produce a high response in patients with internalised anxious worrying or externalised irritability. Not only do they treat the depression but also the fundamental cause. In summary, efficacy data will continue to provide little meaningful clinical information while treatments are tested as "universal" in reference to non-specific conditions such as "major depression". Through use of the spectrum model, therapy can be better fitted to depression subtype, through identification of clinical phenotypes and their causes.