Occipital bending in schizophrenia.

OBJECTIVE: To investigate the prevalence of occipital bending (an occipital lobe crossing or twisting across the midline) in subjects with schizophrenia and matched healthy controls. METHOD: Occipital bending prevalence was investigated in 37 patients with schizophrenia and 44 healthy controls. RESULTS: Ratings showed that prevalence was nearly three times higher among schizophrenia patients (13/37 [35.1%]) than in control subjects (6/44 [13.6%]). Furthermore, those with schizophrenia had greater normalized gray matter volume but less white matter volume and had larger brain-to-cranial ratio. CONCLUSION: The results suggest that occipital bending is more prevalent among schizophrenia patients than healthy subjects and that schizophrenia patients have different gray matter-white matter proportions. Although the cause and clinical ramifications of occipital bending are unclear, the results infer that occipital bending may be a marker of psychiatric illness.

Repetitive transcranial magnetic stimulation for treatment resistant depression: Re-establishing connections.

Repetitive transcranial magnetic stimulation (rTMS) is a relatively recent addition to the neurostimulation armamentarium for treating individuals suffering from treatment refractory depression and has demonstrated efficacy in clinical trials. One of the proposed mechanisms of action underlying the therapeutic effects of rTMS for depression involves the modulation of depression-associated dysfunctional activity in distributed brain networks involving frontal cortical and subcortical limbic regions, via changes to aberrant functional and structural connectivity. Although there is currently a paucity of published data, we review changes to functional and structural connectivity following rTMS for depression. Current evidence suggests an rTMS-induced normalisation of depression-associated dysfunction within and between large scale functional networks, including the default mode, central executive and salience networks, associated with an amelioration of depressive symptoms. Additionally, changes to measures of white matter microstructure, primarily in the dorsolateral prefrontal cortex, have also been reported following rTMS for depression, possibly reversing depression-associated abnormalities. We argue that measures of functional and structural connectivity can be used to optimise rTMS targeting within the dorsolateral prefrontal cortex and also to explore novel rTMS targets for depression. Finally, we discuss the utility of measures of brain connectivity as predictive biomarkers of rTMS treatment response in guiding therapeutic decisions.

A STUDY OF THE PATTERN OF RESPONSE TO rTMS TREATMENT IN DEPRESSION.

BACKGROUND: Considerable research has demonstrated the efficacy of repetitive transcranial magnetic stimulation (rTMS) treatment in patients with depression. However, limited research has described the pattern of response to rTMS treatment or explored possible predictors of the likelihood of treatment response. METHODS: Data from 11 clinical trials (n = 1,132) was pooled and we described the pattern of response to rTMS, rate of response, and remission as well as potential clinical and demographic predictors of response. RESULTS: There was a bimodal pattern of response to rTMS with the response-associated peak at 57% reduction in depression rating scale scores. About 46% of patients achieved response criteria, with 31% completing rTMS treatment in remission. A greater likelihood of response was seen for patients who had less severe depression at baseline, a shorter duration of the current episode, and recurrent rather than single episode of depression. Greater response was also seen in patients treated at higher stimulation intensity. CONCLUSIONS: A meaningful percentage (>40%) of patients respond to a course of rTMS treatment. Response does vary with a number of clinical and demographic variables but none of these variables exert a sufficiently strong influence on response rates to warrant using these criteria to exclude patients from treatment.

Deep brain stimulation for treatment-resistant depression: efficacy, safety and mechanisms of action.

Deep brain stimulation (DBS), a neuromodulation therapy that has been used successfully in the treatment of symptoms associated with movement disorders, has recently undergone clinical trials for individuals suffering from treatment-resistant depression (TRD). Although the small patient numbers and open label study design limit our ability to identify optimum targets and make definitive conclusions about treatment efficacy, a review of the published research demonstrates significant reductions in depressive symptomatology and high rates of remission in a severely treatment-resistant patient group. Despite these encouraging results, an incomplete understanding of the mechanisms of action underlying the therapeutic effects of DBS for TRD is highlighted, paralleling the incomplete understanding of the neuroanatomy of mood regulation and treatment resistance. Proposed mechanisms of action include short and long-term local effects of stimulation at the neuronal level, to modulation of neural network activity.