Neurological soft signs and structural network changes: a longitudinal analysis in first-episode schizophrenia

BACKGROUND

Neurological soft signs (NSS) are often reported in patients with schizophrenia and may vary with psychopathological symptoms during the course of disease. Many cross-sectional neuroimaging studies have shown that NSS are associated with disturbed network connectivity in schizophrenia. However, it remains unclear how these associations change over time during the course of disorder.

METHODS

In present study, 20 patients with first-episode schizophrenia and 20 controls underwent baseline structural magnetic resonance imaging (MRI) scan and at one-year follow-up. Structural network characteristics of patients and controls were analyzed using graph theoretical approach based on MRI data. NSS were assessed using the Heidelberg scale.

RESULTS

At baseline, patients demonstrated significant changes of the local network properties mainly involving regions of the cortical-subcortical-cerebellar circuits compared to healthy controls. For further analysis, the whole patient group was dichotomized into a NSS-persisting and NSS-decreasing subgroup. After one-year follow-up, the NSS-persisting subgroup showed decreased betweenness in right inferior opercular frontal cortex, left superior medial frontal cortex, left superior temporal cortex, right putamen and cerebellum vermis and increased betweenness in right lingual cortex. However, the NSS-decreasing subgroup exhibited only localized changes in right middle temporal cortex, right insula and right fusiform with decreased betweenness, and in left lingual cortex with increased betweenness.

CONCLUSIONS

These findings provide evidence for brain network reorganization subsequent to clinical disease manifestation in patients with first-episode schizophrenia, and support the hypothesis that persisting NSS refer to progressive brain network abnormalities in patients with schizophrenia. Therefore, NSS could help to establish a better prognosis in first-episode schizophrenia patients.

Neurological Soft Signs and Brain Network Abnormalities in Schizophrenia

Neurological soft signs (NSS) are often found in patients with schizophrenia. A wealth of neuroimaging studies have reported that NSS are related to disturbed cortical-subcortical-cerebellar circuitry in schizophrenia. However, the association between NSS and brain network abnormalities in patients with schizophrenia remains unclear. In this study, the graph theoretical approach was used to analyze brain network characteristics based on structural magnetic resonance imaging (MRI) data. NSS were assessed using the Heidelberg scale. We found that there was no significant difference in global network properties between individuals with high and low levels of NSS. Regional network analysis showed that NSS were associated with betweenness centrality involving the inferior orbital frontal cortex, the middle temporal cortex, the hippocampus, the supramarginal cortex, the amygdala, and the cerebellum. Global network analysis also demonstrated that NSS were associated with the distribution of network hubs involving the superior medial frontal cortex, the superior and middle temporal cortices, the postcentral cortex, the amygdala, and the cerebellum. Our findings suggest that NSS are associated with alterations in topological attributes of brain networks corresponding to the cortical-subcortical-cerebellum circuit in patients with schizophrenia, which may provide a new perspective for elucidating the neural basis of NSS in schizophrenia.

Neurological soft signs in aging, mild cognitive impairment, and Alzheimer's disease - the impact of cognitive decline and cognitive reserve

OBJECTIVES

Neurological soft signs (NSS), i.e., minor motor and sensory changes, are a common feature in severe psychiatric disorders. We sought to establish the frequency of NSS in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) on basis of a large population-based sample and to identify their neuropsychological correlates including cognitive reserve.

METHODS

Neurological soft signs were examined using an abbreviated version of the Heidelberg NSS Scale in 221 "old" participants born between 1930 and 1932 (63 with MCI, 15 with AD, 143 healthy old controls) and 256 healthy "young" participants (born between 1950 and 1952) of the population-based interdisciplinary longitudinal study of aging. Subjects received thorough neuropsychological testing; years of school education were used as a proxy for cognitive reserve.

RESULTS

Neurological soft signs scores were significantly (p < 0.001) higher in the AD patients (5.6 ± 3.11) than in the healthy old controls (2.8 ± 1.90) and in the MCI patients (3.0 ± 1.96). This result was confirmed after years of school education, which were inversely correlated (r = -0.25; p < 0.001) with NSS were entered as a covariate. In the patients, but not in the controls, NSS were significantly correlated with deficits in executive functioning and visuospatial functioning. Comparison of NSS scores between "old" (2.84 ± 1.9) and "young" (2.46 ± 1.97) controls yielded only minor, non-significant differences after education (13.86 ± 3.0 vs. 14.61 ± 2.48 years, respectively) was controlled for.

CONCLUSION

Our results demonstrate that NSS are frequently found in mild AD, but not in MCI. NSS refer to frontal-executive deficits and visuospatial dysfunction rather than age per se and can be partly compensated for by cognitive reserve.

A neuropsychiatry service in a state hospital. Adolf Meyer's approach revisited

In the spirit of Adolf Mayer's medico-biological approach to the understanding of mental illnesses the article describes the advantages that neuropsychiatric approach brings to the diagnostic evaluation and treatment of psychiatric patients in a state hospital. Our review discusses the neuropsychiatric approach to the evaluation of state hospital patients with mild, moderate, and severe cognitive disturbances showing the role of neuropsychological testing, electroencephalography (EEG), and brain imaging in the neuropsychiatric assessment of primary and secondary mental illnesses. Neuropsychiatric evaluation helps to assess the peculiarities of movement disorder as a of side effects of regular psychiatric medications, e.g. the differences in diagnostic signs and treatment implication between Parkinson's disease and extrapyramidal syndrome (EPS) as a side effect of neuroleptics as well as the development of abnormal reflexes as a sign of tardive dyskinesia (TD) not directly related to the lesion of upper motor neuron. The article also discusses the development of hypokinetic delirium in the course of treatment of psychiatric patients not only as a side effect of neuroleptics but also of anticonvulsants, increasingly used as the mood stabilizers in modern psychiatry. Since aggressive behavior of psychiatric patients represents one of the major criteria for admission and often long term treatment in a state hospital, special consideration is given to the role of brain paroxysmal activity in the development of aggressive behavior, especially rage attacks, one of the main manifestations of aggressive behavior in a state hospital patients. Correspondingly, the use of anticonvulsants in the treatment of rage attacks is discussed. This article may serve as a model for the use of neuropsychiatric service in improvement of diagnostic evaluation and treatment of psychiatric patients in a state hospital.

Paul E. Meehl's influence on experimental psychopathology: fruits of the nexus of schizotypy and schizophrenia, neurology, and methodology

Paul E. Meehl made numerous contributions to clinical science and a hallmark of many of these contributions was their integrative nature. Meehl's positions on complex topics, especially one such as schizophrenia, were reflective of input from a variety of disciplines and levels of analysis. In this essay the authors focus on Meehl's uniquely rich contribution to our understanding of schizophrenia through his theoretical model of schizotypy, his abiding interest in exploring neurologically based indicators of schizophrenia liability and encouragement to others to pursue such indicators, and his passion for rigorous research methodology. Meehl's contributions in each of these areas continue to influence the direction and research strategies used in experimental psychopathology to illuminate the fundamental nature of schizophrenia. These contributions have also shaped inquiry into many other psychopathological entities.

Reduced cerebellar volume and neurological soft signs in first-episode schizophrenia

Recent studies indicate that morphological and functional abnormalities of the cerebellum are associated with schizophrenia. Since the cerebellum is crucial for motor coordination, one may ask whether the respective changes are associated with motor dysfunction in the disease. To test these hypotheses in a clinical study, we investigated cerebellar volumes derived from volumetric magnetic resonance imaging of 37 first-episode patients with schizophrenia, schizophreniform or schizoaffective disorder and 18 healthy controls matched for age, gender and handedness. To control for potential interindividual differences in head size, intracranial volume was entered as a covariate. Neurological soft signs (NSS) were examined after remission of acute symptoms. Compared with the controls, patients had significantly smaller cerebellar volumes for both hemispheres. Furthermore, NSS in patients were inversely correlated with tissue volume of the right cerebellar hemisphere partialling for intracranial volume. No associations were detected between cerebellar volumes and psychopathological measures obtained at hospital admission when patients were in the acute psychotic state or after remission, treatment duration until remission, treatment response or prognostic factors, respectively. These findings support the hypothesis of cerebellar involvement in schizophrenia and indicate that the respective changes are associated with NSS.