The cerebral neurobiology of anxiety, anxiety displacement, and anxiety denial

Data-driven identification of intensity normalization region based on longitudinal coherency of 18F-FDG metabolism in the healthy brain

OBJECTIVES

In brain ¹⁸F-FDG PET data intensity normalization is usually applied to control for unwanted factors confounding brain metabolism. However, it can be difficult to determine a proper intensity normalization region as a reference for the identification of abnormal metabolism in diseased brains. In neurodegenerative disorders, differentiating disease-related changes in brain metabolism from age-associated natural changes remains challenging. This study proposes a new data-driven method to identify proper intensity normalization regions in order to improve separation of age-associated natural changes from disease related changes in brain metabolism.

METHODS

127 female and 128 male healthy subjects (age: 20 to 79) with brain¹⁸F-FDG PET/CT in the course of a whole body cancer screening were included. Brain PET images were processed using SPM8 and were parcellated into 116 anatomical regions according to the AAL template. It is assumed that normal brain ¹⁸F-FDG metabolism has longitudinal coherency and this coherency leads to better model fitting. The coefficient of determination R² was proposed as the coherence coefficient, and the total coherence coefficient (overall fitting quality) was employed as an index to assess proper intensity normalization strategies on single subjects and age-cohort averaged data. Age-associated longitudinal changes of normal subjects were derived using the identified intensity normalization method correspondingly. In addition, 15 subjects with clinically diagnosed Parkinson's disease were assessed to evaluate the clinical potential of the proposed new method.

RESULTS

Intensity normalizations by paracentral lobule and cerebellar tonsil, both regions derived from the new data-driven coherency method, showed significantly better coherence coefficients than other intensity normalization regions, and especially better than the most widely used global mean normalization. Intensity normalization by paracentral lobule was the most consistent method within both analysis strategies (subject-based and age-cohort averaging). In addition, the proposed new intensity normalization method using the paracentral lobule generates significantly higher differentiation from the age-associated changes than other intensity normalization methods.

CONCLUSION

Proper intensity normalization can enhance the longitudinal coherency of normal brain glucose metabolism. The paracentral lobule followed by the cerebellar tonsil are shown to be the two most stable intensity normalization regions concerning age-dependent brain metabolism. This may provide the potential to better differentiate disease-related changes from age-related changes in brain metabolism, which is of relevance in the diagnosis of neurodegenerative disorders.

The backup is active in Alzheimer's disease: a hypothesis from problem theory

Problem theory distinguishes between six general problems of everyday life, which people work through in turn during childhood, learning to switch between them. One of them requires the protection of a cut-out and an override. People who develop Alzheimer's disease (AD), and apolipoprotein allele epsilon 4 carriers, are preoccupied with this problem, or readily switch back to it. It is the freedom problem, of raising hope or confidence of freedom or power to control. Here people try to raise hope of success with any task on which attention happens to rest. This indiscriminateness means that there is no basis for giving up on a task, or for avoiding dangerous environments. Thus the cut-out is needed when someone becomes stuck on a mental task and the override is needed so as to help in avoiding danger. Activity relevant to the freedom problem is confined to the left hemisphere and the right hemisphere operates the cut-out and override. In providing these two forms of protection the right hemisphere can be said to act as a backup. Accordingly EEG, metabolism, and atrophy findings indicate that both cut-out and override are active in mild clinical impairment, especially among patients who later develop AD. The pattern of atrophy of AD matches what would be expected from disuse caused by an overactive cut-out followed by an overactive override. A parallel loss of testosterone might contribute to the weakening of resistance to infections leading to autoimmune effects.

Computerized content analysis of conversational interactions

The emotional impact of illness sustained by patients, their families, and friends is increasingly recognized as an important dimension of clinical evaluation and intervention. This study first attempted to extend a computerized technique of measuring the magnitude of mental events from a content analysis of speech initially designed for use on single verbal samples or verbal texts to the analysis of conversational interactions. The study then applied this method of extended measurement to conversations concerning seriously ill surgical patients. The authors' objective was to develop a graphic method that illustrates the neuropsychological interchanges occurring in these conversations. Speech samples were recorded during discussions among nurses, surgeons, intensivists, and family members involved in the care and treatment of seriously ill patients hospitalized in the surgical intensive care unit at Barnes-Jewish Hospitals associated with Washington University School of Medicine, St. Louis, Missouri. These samples then were transcribed into computer-readable text files and divided into utterances: uninterrupted speech by a single individual. The utterances were assigned numeric scores by a computer program on each of 14 validated content analysis scales measuring various neuropsychological dimensions. The scores are presented graphically in chronological sequence to illustrate the emotional interactions in these conversations. The graphic representations depicting sequences of computerized content analysis-derived scores for the mental reactions of the speakers in such conversations provide insights into the psychodynamics occurring in such stressful situations.

Posttraumatic embitterment disorder

BACKGROUND

Adjustment and reactive disorders are a heterogeneous group of mental disorders. Diagnostic criteria are vague and scientific research is limited despite the fact that these disorders play a major role in clinical practice.

METHODS

The 'posttraumatic embitterment disorder' (PTED) is introduced as a new concept for a subgroup of adjustment disorders. A case vignette and diagnostic criteria are presented.

RESULTS

Core criteria of PTED are: (1) a single exceptional negative life event precipitates the onset of the illness; (2) the present negative state developped in the direct context of this event; (3) the emotional response is embitterment and feelings of injustice; (4) repeated intrusive memories of the event; (5) emotional modulation is unimpaired, patients can even smile when engaged in thoughts of revenge, and (6) no obvious other mental disorder that can explain the reaction. Additional symptoms are feelings of helplessness, self-blame, rejection of help, suicidal ideation, dysphoria, aggression, down-heartedness, seemingly melancholic depression, unspecific somatic complaints, loss of appetite, sleep disturbances, pain, phobic symptoms in respect to the place or to persons related to the event, reduced drive. Duration is longer than 3 months. Performance in daily activities and roles is impaired.

CONCLUSIONS

PTED is a frequent disorder. The diagnosis of PTED can lead to specific therapeutic interventions. PTED can be discriminated from PTSD, depression, anxiety disorders, and other adjustment disorders.