Visual dysfunction in multiple sclerosis. / Synsproblemer ved multippel sklerose.

Multiple sclerosis can give rise to signs and symptoms from the entire nervous system, including visual impairments. Visual impairments often go unreported because they are not obvious to patients, which means that doctors must ask about them specifically. Regular monitoring of vision is important, however, to provide personalised rehabilitation and assistive technologies, and thereby improve patients' functioning and quality of life.

The utility of a single simple question in the evaluation of patients with myasthenia gravis.

INTRODUCTION: Assessing myasthenia gravis (MG) can be challenging, and multiple scales are available to evaluate disease severity. We evaluated the utility of a single, simple question, as part of the MG evaluation: "What percentage of normal do you feel regarding your MG, 0%-100% normal?" METHODS: A retrospective chart review of patients attending the neuromuscular clinic from January 2014 to December 2015 was performed. Responses were correlated with symptoms and signs, the Quantitative Myasthenia Gravis Score (QMGS), the Myasthenia Gravis Impairment Index (MGII), and the 15-item Myasthenia Gravis Quality of Life scale (MG-QOL15). RESULTS: The total cohort included 169 patients. The percentage of normal correlated strongly with limb muscle weakness and MG scales, moderately with bulbar and respiratory symptoms, and weakly with ocular manifestations. DISCUSSION: The question, "What percentage of normal do you feel regarding your MG?" is feasible and valid, and can be incorporated easily into routine clinical evaluation. Muscle Nerve 57: 240-244, 2018.

Functional eye movement disorders.

Functional (psychogenic) eye movement disorders are perhaps less established in the medical literature than other types of functional movement disorders. Patients may present with ocular symptoms (e.g., blurred vision or oscillopsia) or functional eye movements may be identified during the formal examination of the eyes in patients with other functional disorders. Convergence spasm is the most common functional eye movement disorder, but functional gaze limitation, functional eye oscillations (also termed "voluntary nystagmus"), and functional convergence paralysis may be underreported. This chapter reviews the different types of functional eye movement abnormalities and provides a practical framework for their diagnosis and management.

Smooth pursuit eye movement, prepulse inhibition, and auditory paired stimuli processing endophenotypes across the schizophrenia-bipolar disorder psychosis dimension.

BACKGROUND: This study examined smooth pursuit eye movement (SPEM), prepulse inhibition (PPI), and auditory event-related potentials (ERP) to paired stimuli as putative endophenotypes of psychosis across the schizophrenia-bipolar disorder dimension. METHODS: Sixty-four schizophrenia probands (SZP), 40 psychotic bipolar I disorder probands (BDP), 31 relatives of SZP (SZR), 26 relatives of BDP (BDR), and 53 healthy controls (HC) were tested. Standard clinical characterization, SPEM, PPI, and ERP measures were administered. RESULTS: There were no differences between either SZP and BDP or SZR and BDR on any of the SPEM, PPI, or ERP measure. Compared with HC, SZP and BDP had lower SPEM maintenance and predictive pursuit gain and ERP theta/alpha and beta magnitudes to the initial stimulus. PPI did not differ between the psychosis probands and HC. Compared with HC, SZR and BDR had lower predictive pursuit gain and ERP theta/alpha and beta magnitudes to the first stimulus with differences ranging from a significant to a trend level. Neither active symptoms severity nor concomitant medications were associated with neurophysiological outcomes. SPEM, PPI, and ERP scores had low intercorrelations. CONCLUSION: These findings support SPEM predictive pursuit and lower frequency auditory ERP activity in a paired stimuli paradigm as putative endophenotypes of psychosis common to SZ and BD probands and relatives. PPI did not differ between the psychosis probands and HC. Future studies in larger scale psychosis family samples targeting putative psychosis endophenotypes and underlying molecular and genetic mediators may aid in the development of biology-based diagnostic definitions.

Role of anticipation and prediction in smooth pursuit eye movement control in Parkinson's disease.

Patients with Parkinson's disease (PD) have difficulties in the control of self-guided (i.e., internally driven) movements. The basal ganglia provide a nonspecific internal cue for the development of a preparatory activity for a given movement in the sequence of repetitive movements. Controversy surrounds the question of whether PD patients are capable of (1) anticipating (before an external trigger appears; i.e., anticipation) and (2) predicting movement velocity once a moving target shortly disappears from the visual scene (i.e., prediction). To dissociate between these two components, we examined internally driven (extraretinal generated) smooth pursuit eye movements in PD patients and age-matched healthy controls by systematically varying target blanking periods of a trapezoidally moving target in four paradigms (initial blanking, midramp blanking, blanking after a short ramp, and no blanking). Compared to controls, PD patients showed (1) decreased smooth pursuit gain (without blanking), (2) deficient anticipatory pursuit (prolonged pursuit initiation latency; reduced eye velocity before target onset in the early onset blanking paradigm), and (3) preserved extraretinal predictive pursuit velocity (midramp target blanking). Deficient anticipation of future target motion was not related to either disease duration or the general motor impairment (UPDRS). We conclude that PD patients have difficulties in anticipating future target motion, which may play a role for the mechanisms involved in deficient gait initiation and termination of PD. In contrast, they remain unimpaired in their capacity of building up an internal representation of continuous target motion. This may explain the clinical advantage of medical devices that use visual motion to improve gait initiation (e.g., "PD glasses").

Predictive pursuit association with deficits in working memory in psychosis.

BACKGROUND: Deficits in smooth pursuit eye movements are an established phenotype for schizophrenia (SZ) and are being investigated as a potential liability marker for bipolar disorder. Although the molecular determinants of this deficit are still unclear, research has verified deficits in predictive pursuit mechanisms in SZ. Because predictive pursuit might depend on the working memory system, we have hypothesized a relationship between the two in healthy control subjects (HC) and SZ and here examine whether it extends to psychotic bipolar disorder (BDP). METHODS: Volunteers with SZ (n = 38), BDP (n = 31), and HC (n = 32) performed a novel eye movement task to assess predictive pursuit as well as a standard visuospatial measure of working memory. RESULTS: Individuals with SZ and BDP both showed reduced predictive pursuit gain compared with HC (p < .05). Moreover, each patient group showed worse performance in visuospatial working memory compared with control subjects (p < .05). A strong correlation (r = .53, p = .007) was found between predictive pursuit gain and working memory in HC, a relationship that showed a trend correlation within the BDP group but not among SZ. CONCLUSIONS: Individuals with SZ and BDP showed similar deficits in predictive pursuit, suggesting that this alteration could be a characteristic trait of the psychosis domain. The correlation between predictive pursuit and working memory in HC supports the assumption that working memory is related to predictive pursuit eye movements; however, the degradation of working memory in people with psychosis disrupts its association with eye-tracking behavior.

Relationships between exploratory eye movement dysfunction and clinical symptoms in schizophrenia.

AIM: Many psychophysiological tests have been widely researched in the search for a biological marker of schizophrenia. The exploratory eye movement (EEM) test involves the monitoring of eye movements while subjects freely view geometric figures. Suzuki et al. (2009) performed discriminant analysis between schizophrenia and non-schizophrenia subjects using EEM test data; consequently, clinically diagnosed schizophrenia patients were identified as having schizophrenia with high probability (73.3%). The aim of the present study was to investigate the characteristics of schizophrenia patients who were identified as having schizophrenia on EEM discriminant analysis (SPDSE) or schizophrenia patients who were identified as not having schizophrenia on EEM discriminant analysis (SPDNSE). METHODS: The data for the 251 schizophrenia subjects used in the previous discriminant-analytic study were analyzed, and the demographic or symptomatic characteristics of SPDSE and SPDNSE were investigated. As for the symptomatic features, a factor analysis of the Brief Psychiatric Rating Scale (BPRS) rating from the schizophrenia subjects was carried out. RESULTS: Five factors were found for schizophrenia symptoms: excitement/hostility; negative symptoms; depression/anxiety; positive symptoms; and disorganization. SPDSE had significantly higher factor scores for excitement/hostility, negative symptoms and disorganization than SPDNSE. Furthermore, the BPRS total score for the SPDSE was significantly higher than that for the SPDNSE. CONCLUSION: SPDSE may be a disease subtype of schizophrenia with severe symptoms related to excitement/hostility, negative symptoms and disorganization, and EEM parameters may detect this subtype. Therefore, the EEM test may be one of the contributors to the simplification of the heterogeneity of schizophrenia.

Relating vision status to academic achievement among year-2 school children in Malaysia.

BACKGROUND: Vision affects daily activities, but of particular importance is the impact upon the learning process. Many studies have been conducted to establish the relationship between vision problems and academic performance. The results are varied, however, and suggest additional research is needed with particular care given to study design. METHODS: This study included 1,103 year-2 school children enrolled in 7 public schools in the Klang Valley region of Malaysia. There were an equal proportion of males (50.6%) and females (49.4%). The testing battery was designed to assess visual acuity, ocular muscle balance, visual analysis skills, visual-spatial skills, and visual-motor integration skills. RESULTS: Children with average and above-average achievement showed a different visual performance profile from those children with low academic achievement. They had a statistically significant better pass rate in physical aspects (visual acuity), physiological aspects (ocular motor balance), and perceptual aspects (visual-motor integration/visual-spatial and visual-analysis skills). CONCLUSION: Children with low academic achievement are more likely to exhibit problems in visual acuity, ocular motor balance, visual-motor integration and most all components of visual analysis skills. This finding supports the concept that visual performance is key to learning and therefore of chief concern as to school achievement.

Atypical reflexive gaze patterns on emotional faces in autism spectrum disorders.

Atypical scan paths on emotional faces and reduced eye contact represent a prominent feature of autism symptomatology, yet the reason for these abnormalities remains a puzzle. Do individuals with autism spectrum disorders (ASDs) fail to orient toward the eyes or do they actively avoid direct eye contact? Here, we used a new task to investigate reflexive eye movements on fearful, happy, and neutral faces. Participants (ASDs: 12; controls: 11) initially fixated either on the eyes or on the mouth. By analyzing the frequency of participants' eye movements away from the eyes and toward the eyes, respectively, we explored both avoidance and orientation reactions. The ASD group showed a reduced preference for the eyes relative to the control group, primarily characterized by more frequent eye movements away from the eyes. Eye-tracking data revealed a pronounced influence of active avoidance of direct eye contact on atypical gaze in ASDs. The combination of avoidance and reduced orientation into an individual index predicted emotional recognition performance. Crucially, this result provides evidence for a direct link between individual gaze patterns and associated social symptomatology. These findings thereby give important insights into the social pathology of ASD, with implications for future research and interventions.

The influence of side effect of antipsychotic on the course of treatment in adolescent.

The use of antipsychotics in treatment of children and adolescents requires good knowledge of psychopathology, psychofarmacotherapy, developmental processes and family relations. It is necessary to have parental consent for the use of a medication in this age, with previous explanation of therapeutic goals, limitations and possible side effects of antipsychotics. The number of antipsychotics registered for use in children and adolescents is quite limited. The combination of clinical experience of those working with psychotic adolescents and a good collaboration with parents, creates a therapeutic space where good results in treatment can be achieved. Side effects, though rarely, can bring in question the course of treatment and disorder follow up. In this work we will present a 14-year old girl adolescent with psychotic symptoms, in which case the course of treatment and discontinuance of therapy was caused by a side effect - an oculogyric crisis.

Academic behaviors in children with convergence insufficiency with and without parent-reported ADHD.

PURPOSE: To determine if children with symptomatic Convergence Insufficiency without the presence of parent-reported Attention Deficit Hyperactivity Disorder (ADHD) have higher scores on the academic behavior survey (ABS). METHODS: The ABS is a 6-item survey that evaluates parent concern about school performance and the parents' perceptions of the frequency of problem behaviors that their child may exhibit when reading or performing schoolwork (such as difficulty completing work, avoidance, and inattention). Each item is scored on an ordinal scale from 0 (Never) to 4 (Always) with a total score ranging from 0 to 24. The survey was administered to the parents of 212 children 9- to 17-year old (mean age 11.8 years.) with symptomatic convergence insufficiency before enrolling into the Convergence Insufficiency Treatment Trial and to 49 children with normal binocular vision (NBV) (mean age 12.5 years). The parents reported whether the child had ADHD, and this information was used to divide the symptomatic convergence insufficiency group into the convergence insufficiency with parent report of ADHD or convergence insufficiency with parent report of no ADHD groups. RESULTS: Sixteen percent of the convergence insufficiency group and 6% of the NBV group were classified as ADHD by parental report. An analysis of covariance showed that the total ABS score for the symptomatic convergence insufficiency with parent report of ADHD group (15.6) was significantly higher than the symptomatic convergence insufficiency with parent report of no ADHD group (11.7, p = 0.001) and the NBV group (8.7, p < 0.0001). Children with convergence insufficiency with parent report of no ADHD scored significantly higher on the ABS than the NBV group (p = 0.036). CONCLUSIONS: Children with symptomatic convergence insufficiency with parent report of no ADHD scored higher on the ABS, when compared to children with NBV. Children with parent report of ADHD or related learning problems may benefit from comprehensive vision evaluation to assess for the presence of convergence insufficiency.

Neuropsychological correlates of eye movement abnormalities in schizophrenic patients and their unaffected relatives.

Impairments on neuropsychological and eye movement tasks have been demonstrated in schizophrenic patients and also reported in their unaffected relatives. However, it is not clear to what extent these phenotypes overlap. This study examined the relationship between specific eye movement and neuropsychological measures. The relationship between performance on eye movement and neuropsychological tasks was measured in 79 schizophrenic patients (63% from multiply affected families), 129 of their healthy first-degree relatives, and 72 normal controls. Antisaccade scores were correlated with most measures of neurocognitive functioning, and this correlation was strongest in schizophrenic patients in all cases. In the schizophrenic patients, but not their relatives or controls, the antisaccade distractibility error (ADE) score correlated significantly with current intelligence, verbal memory (immediate and delayed recall), and associative learning. In the case of crystallised IQ and delayed verbal memory, smaller correlations were present in unaffected relatives, although neither survived Bonferroni correction. Smooth pursuit performance was unrelated to any neuropsychological measure. Our study suggests that antisaccade errors are likely to represent part of a generalized neuropsychological deficit in schizophrenia.

Vertical and horizontal integrator failure in a ponto-medullary infarction: A possible role for paramedian tract neurons.

Gaze-evoked nystagmus is caused by a "leaky" neural integrator, which fails to maintain eccentric gaze positions after centrifugal eye movements. It is usually observed as the result of toxic, metabolic or paraneoplastic disorders, rather than single structural lesions. We demonstrate a case of an omnidirectional gaze-evoked nystagmus due to an ischemic paramedian ponto-medullar infarction. The most probable explanation is a damage of paramedian tract neurons, which have been recently recognized as a site of neural integration.

Is persistent ketamine use a valid model of the cognitive and oculomotor deficits in schizophrenia?

BACKGROUND: Acute ketamine has been shown to model features of schizophrenia such as psychotic symptoms, cognitive deficits and smooth pursuit eye movement dysfunction. There have been suggestions that chronic ketamine may also produce an analogue of the disorder. In this study, we investigated the effect of persistent recreational ketamine use on tests of episodic and working memory and on oculomotor tasks of smooth pursuit and pro- and antisaccades. METHODS: Twenty ketamine users were compared with 1) 20 first-episode schizophrenia patients, 2) 17 polydrug control subjects who did not use ketamine but were matched to the ketamine users for other drug use, and 3) 20 non-drug-using control subjects. All groups were matched for estimated premorbid IQ. RESULTS: Ketamine users made more antisaccade errors than both control groups but did not differ from patients. Ketamine users performed better than schizophrenia patients on smooth pursuit, antisaccade metrics, and both memory tasks but did not differ from control groups. CONCLUSIONS: Problems inhibiting reflexive eye movements may be a consequence of repeated ketamine self-administration. The absence of any other oculomotor or cognitive deficit present in schizophrenia suggests that chronic self-administration of ketamine may not be a good model of these aspects of the disorder.

Finding of abnormal scanning behavior in the Span of Apprehension task in schizophrenia but diagnostic non-specificity of sum scores.

Deficits in the Span of Apprehension (SOA) task have been discussed controversially as a trait marker of schizophrenia. The task was administered to 47 schizophrenia and 48 depressed patients as well as to 46 controls. Results indicate a non-specificity of the SOA sum scores but differential abnormalities in spatial visual processing.

Neurological evaluation of patients with Gaucher disease diagnosed as type 1.

Type 1 Gaucher disease (GD1) is characterised by lack of central nervous system involvement; however, there are several reports of associated neurological manifestations. The aim of this study was to systematically evaluate neurological manifestations in 31 patients with GD1 (12 males and 19 females; mean age 39.4 (range 5-77) years). Participants underwent a complete neurological examination and cognitive tests. Investigation of symptoms and medication intake, and motor and sensory electroneurograms were obtained. 30.7% of adult patients had neurological deficits, including psychomotor delay, parkinsonism, dementia, impaired saccadic ocular movements and peripheral nerve dysfunction. Three patients were redefined as type 3 GD. Electrodiagnosis was performed on 15 patients; 26.7% had reduced amplitude and/or abnormal waveforms in at least three nerves, 33.3% had a mild reduction in amplitude of two nerves and 40% had amplitude reduction in one nerve. Patients with three or more affected nerves had additional neurological symptoms. Our results demonstrate that neurological alterations occur in patients diagnosed with GD1, and subclinical peripheral neuropathy is a frequent finding.

[Parallel processing of motion vision].

Several neuropsychological studies have reported dissociation between motion vision and object vision. One patient with motion blindness had a bilateral MT/V5 lesion and could see objects, but could not see the motion of the objects (Zihl et al, 1983). By contrast, some blindsight patients with primary visual cortex lesions cannot see objects but can see their movement (e.g. Riddoch, 1917). These results imply that movement vision and form vision rely on independent mechanisms. However one patient with motion blindness had controversial symptoms concerning motion vision. She could not perceive the movement of objects, although she could walk without colliding with obstacles and could catch incoming objects. It has also been reported that patients with a bilateral parietal lesion had well-preserved primary motion vision, but had problems walking and catching a ball (Vaina, 1998). Therefore, motion for vision and motion for action might have independent mechanisms. Such dissociation has also been noted in patients with Bálint syndrome. Some patients behave like a blind person but can walk and catch a ball, while other patients bump into obstacles while walking. These results indicate that the neural bases of motion vision are distinct from those of form vision and that there are subdivisions of motion vision.