Neuromotor markers of risk for schizophrenia

Investigating Gait, Movement, and Coordination in Children with Neurodevelopmental Disorders: Is There a Role for Motor Abnormalities in Atypical Neurodevelopment?

Motor abnormalities have been suggested to play a role in most neuropsychiatric disorders, as a potential generic neurodevelopmental vulnerability. However, they still represent a neglected area, with a paucity of empirical studies, especially in pediatric populations. This case-control study aimed to comprehensively assess motor functioning in children with atypical neurodevelopment and investigate whether any socio-demographic or clinical characteristics would concur with motor difficulties to distinguish children with neurodevelopmental disorders (NDD) from healthy controls. Socio-demographic (age and gender) and clinical (intelligence quotient, gait, movement, and coordination) data were collected on 114 children aged 5-15 (83 with NDD, 31 healthy controls). Male children were at significantly higher risk for NDD (OR: 13.023, p < 0.001). Furthermore, there was a statistically significant interaction between the total intelligence quotient and overall coordination such that increasing levels of total intelligence quotient appeared to protect against the likelihood of being diagnosed with an NDD, but only in the context of a preserved coordination (OR: 0.964, p = 0.038). Collectively, results may have important public health implications, as they point towards the development of new approaches to establish an early prognosis in neurodevelopment, including assessing motor difficulties and mitigating their impact on children's quality of life.

Handwriting movements for assessment of motor symptoms in schizophrenia spectrum disorders and bipolar disorder

The main aim of the present study was to explore the value of several measures of handwriting in the study of motor abnormalities in patients with bipolar or psychotic disorders. 54 adult participants with a schizophrenia spectrum disorder or bipolar disorder and 44 matched healthy controls, participated in the study. Participants were asked to copy a handwriting pattern consisting of four loops, with an inking pen on a digitizing tablet. We collected a number of classical, non-linear and geometrical measures of handwriting. The handwriting of patients was characterized by a significant decrease in velocity and acceleration and an increase in the length, disfluency and pressure with respect to controls. Concerning non-linear measures, we found significant differences between patients and controls in the Sample Entropy of velocity and pressure, Lempel-Ziv of velocity and pressure, and Higuchi Fractal Dimension of pressure. Finally, Lacunarity, a measure of geometrical heterogeneity, was significantly greater in handwriting patterns from patients than from controls. We did not find differences in any handwriting measure on function of the specific diagnosis or the antipsychotic dose. Results indicate that participants with a schizophrenia spectrum disorder or bipolar disorder exhibit significant motor impairments and that these impairments can be readily quantified using measures of handwriting movements. Besides, they suggest that motor abnormalities are a core feature of several mental disorders and they seem to be unrelated to the pharmacological treatment.

Motor Abnormalities: From Neurodevelopmental to Neurodegenerative Through "Functional" (Neuro)Psychiatric Disorders

Background

Motor abnormalities (MAs) of severe mental disorders have been traditionally neglected both in clinical practice and research, although they are an increasing focus of attention because of their clinical and neurobiological relevance. For historical reasons, most of the literature on MAs has been focused to a great extent on schizophrenia, and as a consequence their prevalence and featural properties in other psychiatric or neuropsychiatric disorders are poorly known. In this article, we evaluated the extent to which catatonic, extrapyramidal and neurological soft signs, and their associated clinical features, are present transdiagnostically.

Methods

We examined motor-related features in neurodevelopmental (schizophrenia, obsessive compulsive disorder, autism spectrum disorders), "functional" (nonschizophrenic nonaffective psychoses, mood disorders) and neurodegenerative (Alzheimer's disease) disorders. Examination of the literature revealed that there have been very few comparisons of motor-related features across diagnoses and we had to rely mainly in disorder-specific studies to compare it transdiagnostically.

Results

One or more motor domains had a substantial prevalence in all the diagnoses examined. In "functional" disorders, MAs, and particularly catatonic signs, appear to be markers of episode severity; in chronic disorders, although with different degree of strength or evidence, all motor domains are indicators of both disorder severity and poor outcome; lastly, in Alzheimer's disease they are also indicators of disorder progression.

Conclusions

MAs appear to represent a true transdiagnostic domain putatively sharing neurobiological mechanisms of neurodevelopmental, functional or neurodegenerative origin.

Physical manifestations of neurodevelopmental disruption: are minor physical anomalies part of the syndrome of schizophrenia?

The well-documented excess of minor physical anomalies (MPAs) among individuals with schizophrenia generally supports the neurodevelopmental model, which posits that both genetic and environmental factors contribute to structural and functional brain changes in the intrauterine and perinatal periods that predispose one to developing schizophrenia. This review synthesizes select areas of research findings on MPAs to address the question, Are MPAs part of the syndrome of schizophrenia? Although MPAs are not specific to schizophrenia, their presence in some patients indicates that aberrations in the development of the nervous system contribute to risk for the disorder. The broadly defined, heterogeneous MPA construct may be of limited value in further elucidating the specific pathophysiology of schizophrenia, though particular anomalies, such as those pertaining to nasal volumes, palatal abnormalities, or craniofacial morphology, may be informative. Given the availability of more sophisticated microarray technologies, and in light of recent findings on spontaneous mutations in patients with schizophrenia, it is possible that MPAs will prove to be useful in identifying etiologic subtypes and/or the loci of genetic risk factors. It remains to be determined whether MPAs-which, of course, are fixed markers present throughout childhood and adolescence well before the onset of the prodrome and psychosis-may have utility in terms of risk stratification for future preventive efforts. Taken together, research findings on MPAs indicate that these minor anomalies are indeed part of some schizophrenia syndromes, representing a stable systemic or physical set of manifestations of the underlying neurodevelopmental processes that lead to the illness.

Fine motor function and neuropsychological deficits in individuals at risk for schizophrenia

Deficits in fine motor function and neuropsychological performance have been described as risk factors for schizophrenia. In the Basel FEPSY study (Früherkennung von Psychosen; English: Early Detection of Psychosis) individuals at risk for psychosis were identified in a screening procedure (Riecher-Rössler et al. 2005). As a part of the multilevel assessment, 40 individuals at risk for psychosis and 42 healthy controls matched for age, sex and handedness were investigated with a fine motor function test battery and a neuropsychological test battery. Individuals at risk showed lower performances in all subtests of the fine motor function tests, predominantly in dexterity and velocity (wrist/fingers and arm/hand). In the neuropsychological test battery, individuals at risk performed less well compared to healthy controls regarding sustained attention, working memory and perseveration. The combined evaluation of the two test batteries (neuropsychological and fine motor function) separates the two groups into individuals at risk and healthy controls better than each test battery alone. A multilevel approach might therefore be a valuable contribution to detecting beginning schizophrenia.

Ethics of early prevention in schizophrenia

OBJECTIVE

To represent a cross-section of current thinking on the ethics of early (primary) prevention in schizophrenia.

METHOD

Ethical considerations presented at the First Australian Schizophrenia Prevention Conference, Sydney, March 1999, particularly from the final session on 'Ethics', are recorded here together with complementary referenced material.

RESULTS

Ethical concerns arise in the arenas of research over clinical priorities; screening ethics, including stigma, confidentiality, informed consent and support required through waiting periods; and the ethics of prolonged assessments in the absence of disorder, the right not to know and the possible ethical prematurity or otherwise of screening for schizophrenia.

CONCLUSIONS

There are several legitimate ethical concerns that must be understood and addressed by those undertaking the developing of primary preventive measures in schizophrenia. Such measures must still be regarded as more experimental the further ahead the measures are undertaken from the onset of the disorder. Anticipatory ethical guidelines should be developed to inform such research.