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

Associations between neurological soft signs, executive functions, and brain-derived neurotrophic factor in boys with attention-deficit hyperactivity disorder

Background

To determine the association between neurological soft signs, executive functions, and serum brain-derived neurotrophic factor (BDNF) levels in children with attention-deficit hyperactivity disorder (ADHD).

Methods

Serum BDNF levels were measured in 87 drug-naive boys with ADHD, aged 7-12 years. The Revised Physical and Neurological Examination for Subtle Signs for neurological soft signs, Stroop Color-Word Test for attention functions, and Judgment of Line Orientation Test (JLOT) for visuospatial abilities were performed.

Results

Age correlated negatively with dysrhythmia, total time, and total overflow in timed movements, Stroop Color-Word Time (SCWT), and serum BDNF levels. The JLOT significantly negatively correlated with Total Gaits and Stations (P1) and Total Time in Timed Movements (adjusted R 2 = 0.247). In addition, SCWT maintained a significant correlation with Total Overflow in Timed Movements (adjusted R 2 = 0.206). There was no correlation between serum BDNF levels and NSS.

Conclusion

The association between NSS, visuospatial abilities, and selective attention may express a maturational delay in ADHD pathophysiology. Moreover, BDNF may play a role in this maturational delay. Future studies should investigate the contribution of BDNF to neuronal maturation in ADHD.

Executive function abilities in cognitively healthy young and older adults-A cross-sectional study

A prominent feature of cognitive aging is the decline of executive function (EF) abilities. Numerous studies have reported that older adults perform poorer than younger adults in such tasks. In this cross-sectional study, the effect of age on four EFs, inhibition, shifting, updating, and dual-tasking, was examined in 26 young adults (mean 21.18  years) and 25 older adults (mean 71.56  years) with the utilization of a pair of tasks for each EF. The tasks employed for DT were the Psychological Refractory Period paradigm (PRP) and a modified test for everyday attention, for inhibition the Stroop and Hayling sentence completion test (HSCT), for shifting a task switching paradigm and the trail making test (TMT), and for updating the backward digit span (BDS) task and a n-back paradigm. As all participants performed all tasks, a further aim was to compare the size of the age-related cognitive decline among the four EFs. Age-related decline was observed in all four EFs in one or both of the tasks employed. The results revealed significantly poorer performance in the older adults in the response times (RTs) of the PRP effect, interference score of the Stroop, RT inhibition costs of the HSCT, RT and error-rate shifting costs of the task switching paradigm, and the error-rate updating costs of the n-back paradigm. A comparison between the rates of decline revealed numerical and statistically significant differences between the four EFs, with inhibition showing the greatest decline, followed by shifting, updating, and dual-tasking. Thus, we conclude that with age, these four EFs decline at different rates.

Correlates of neurological soft signs in bipolar disorder

Recent research has focused on neurological soft signs (NSS) in bipolar disorder (BD), but there is still scarce evidence on their correlates with other relevant variables. The aim of this study was to explore the association between NSS and clinical demographic, neurocognitive, and functional variables. Eighty-eight euthymic BD patients were included in whom NSS were assessed using the Neurological Evaluation Scale. All subjects performed an extensive neurocognitive battery selected to assess premorbid IQ, attention, language, verbal memory, and executive functions. Psychosocial outcomes were assessed by means of the Functioning Assessment Short Test. Among the demographical variables, NSS tended to be negatively associated with years of education and increased with age. Likewise, NSS were higher in BD type I than in BD type II, but independent of age at illness onset and number of previous affective episodes. There was a negative correlation between NSS and premorbid IQ, as well as with performance in attention, language, and executive functions. Results tended to be unchanged when controlled for potential confounders. Although NSS were associated with poor psychosocial functioning in the bivariate analysis, when added to a multiple regression model including neurocognition, these neurological features did not significantly contribute to the variance of the functional outcome. Our findings contribute to a better characterization of NSS in BD; their potential clinical and theoretical implications are discussed in the manuscript.

Higher-Level Executive Functions in Healthy Elderly and Mild Cognitive Impairment: A Systematic Review

Mild Cognitive Impairment (MCI) is a clinical syndrome characterized by a moderate decline in one or more cognitive functions with a preserved autonomy in daily life activities. MCI exhibits cognitive, behavioral, psychological symptoms. The executive functions (EFs) are key functions for everyday life and physical and mental health and allow for the behavior to adapt to external changes. Higher-level executive functions develop from basic EFs (inhibition, working memory, attentional control, and cognitive flexibility). They are planning, reasoning, problem solving, and fluid intelligence (Gf). This systematic review investigates the relationship between higher-level executive functions and healthy and pathological aging, assuming the role of executive functions deficits as a predictor of cognitive decline. The systematic review was conducted according to the PRISMA Statement. A total of 73 studies were identified. The results indicate that 65.8% of the studies confirm significant EFs alterations in MCI (56.8% planning, 50% reasoning, 100% problem solving, 71.4% fluid intelligence). These results seem to highlight a strong prevalence of higher-level executive functions deficits in MCI elderly than in healthy elderly.

Successful and Unsuccessful Brain Aging in Pets: Pathophysiological Mechanisms behind Clinical Signs and Potential Benefits from Palmitoylethanolamide Nutritional Intervention

Simple Summary

Cognitive dysfunction syndrome is a common yet underreported neurodegenerative disorder of elderly dogs and cats and a natural model of human Alzheimer’s disease. The increasingly expanding life expectancy means a larger proportion of affected animals in the coming decades. Although far from being curative, available treatments are more effective the sooner they are started. Educating veterinary practitioners and owners in the early recognition of age-related cognitive dysfunction is thus mandatory. By shedding light on the mechanism underlying the disease, novel and more effective approaches might be developed. Emerging evidence shows that successful and unsuccessful brain aging share a common underlying mechanism that is neuroinflammation. This process involves astrocytes, microglia, and mast cells and has a restorative homeostatic intent. However, for reasons not fully elucidated yet, neuroinflammation can also exert detrimental consequences substantially contributing to neurodegeneration. Here we summarize the evidence accumulated so far on the pathogenic role of neuroinflammation in the onset and progression of age-related neurodegenerative disorders, such as Alzheimer’s disease. The potential benefit of palmitoylethanolamide dietary intervention in rebalancing neuroinflammation and exerting neuroprotection is also discussed.

Abstract

Canine and feline cognitive dysfunction syndrome is a common neurodegenerative disorder of old age and a natural model of human Alzheimer’s disease. With the unavoidable expanding life expectancy, an increasing number of small animals will be affected. Although there is no cure, early detection and intervention are vitally important to delay cognitive decline. Knowledge of cellular and molecular mechanisms underlying disease onset and progression is an equally decisive factor for developing effective approaches. Uncontrolled neuroinflammation, orchestrated in the central nervous system mainly by astrocytes, microglia, and resident mast cells, is currently acknowledged as a hallmark of neurodegeneration. This has prompted scientists to find a way to rebalance the altered crosstalk between these cells. In this context, great emphasis has been given to the role played by the expanded endocannabinoid system, i.e., endocannabinoidome, because of its prominent role in physiological and pathological neuroinflammation. Within the endocannabinoidome, great attention has been paid to palmitoylethanolamide due to its safe and pro-homeostatic effects. The availability of new ultramicronized formulations highly improved the oral bioavailability of palmitoylethanolamide, paving the way to its dietary use. Ultramicronized palmitoylethanolamide has been repeatedly tested in animal models of age-related neurodegeneration with promising results. Data accumulated so far suggest that supplementation with ultramicronized palmitoylethanolamide helps to accomplish successful brain aging.

Neurological soft signs (NSS) and cognitive deficits in HIV associated neurocognitive disorder

Neurological soft signs (NSS) are frequently found in severe mental disorders, such as Alzheimer's disease, schizophrenia or HIV associated neurocognitive disorder (HAND) which includes asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND) and HIV-associated dementia. To characterize NSS in patients with HIV we examined them with respect to neuropsychological deficits typically found in the disorder. 67 HIV + patients without a history of head trauma, opportunistic infections, severe psychiatric disorders or acute confounding comorbidities of the Central nervous system (CNS) were recruited. NSS and neuropsychological deficits were examined on the Heidelberg scale and the Cambridge Neuropsychological Test Automated Battery (CANTAB), respectively. Semantic and phonemic verbal fluency were additionally established. According to NIMH and NINDS criteria, 18 patients were diagnosed with ANI and 21 with MND, 28 showed no cognitive deficits. NSS total scores were significantly correlated with several cognitive domains and NSS subscales. These correlations were confirmed when motor performance was entered as a covariate. According to our findings, NSS in HIV positive patients are significantly correlated with deficits in a broad range of neuropsychological domains. Similar findings were reported in schizophrenia, emphasizing the transdiagnostic character of NSS and supporting NSS examination in screening HIV patients for HAND.

Neurological soft signs (NSS) and brain morphology in patients with chronic schizophrenia and healthy controls

Subtle abnormalities in sensory integration, motor coordination and sequencing of complex motor acts or neurological soft signs (NSS) are characteristic phenomena in patients with schizophrenia at any stage of the illness. Previous MRI studies in schizophrenia found NSS to be associated with cortical, thalamic and cerebellar changes. Since these studies mainly focused on first-episode or recent onset schizophrenia, the cerebral correlates of NSS in chronic schizophrenia remained rather unclear. 49 middle-aged patients with chronic schizophrenia with a mean duration of illness of 20.3 ± 14.0 years and 29 healthy subjects matched for age and sex were included. NSS were examined on the Heidelberg Scale and correlated to grey matter (GM) by using whole brain high resolution magnetic resonance imaging (3 Tesla) with SPM12/CAT12 analyses. As expected, NSS in patients were significantly (p≤0.001) elevated in contrast to healthy controls, a finding, which not only applied to NSS total score, but also to the respective subscales "motor coordination", "sensory integration", "complex motor tasks", "right/left and spatial orientation" and "hard signs". Within the patient group NSS total scores were significantly correlated to reduced GM in right lingual gyrus, left parahippocampal gyrus, left superior temporal gyrus, left thalamus (medial dorsal nucleus) and left posterior lobe of the cerebellum (declive). Respective negative associations could also be revealed for the subscales "motor coordination", "complex motor tasks" and "right/left and spatial orientation". These findings remained significant after FWE-correction for multiple comparisons and were confirmed when years of education, chlorpromazine-equivalents or variables indicating the severity of psychopathology were introduced as additional covariates. According to our results lingual, parahippocampal, superior temporal, inferior and middle frontal gyri, thalamus and cerebellum have to be considered as important sites of NSS in chronic schizophrenia. That these findings only applied for patients but not healthy controls may indicate a different pathogenesis of NSS.

Associations between brain structural networks and neurological soft signs in healthy adults

Neurological soft signs (NSS), as minor neurological deficits, have been identified in several psychiatric disorders, especially in schizophrenia. However, it's unclear how the neuropathological processes of the disease affect NSS related brain morphological changes and whether it is confounded by the use of medication. As NSS also exist in healthy people, the potential confounding effects of psychopathology or medication will be excluded if NSS are investigated in healthy people. Therefore, we applied a novel multivariate approach, source-based morphometry (SBM), to study structural networks in relation to NSS in healthy adults based on structural magnetic resonance imaging (MRI) data. The Heidelberg Scale was applied to evaluate NSS. Using SBM, we constructed structural networks and investigated their associations with NSS in healthy adults. Six grey matter (GM) structural networks were identified. Sensory integration subscores were associated with the cerebellar component and the cortico-basal ganglia-thalamic component. Motor coordination subscores and total NSS scores were associated with the sensorimotor component. The present findings indicated that structural network abnormalities in cerebellar, subcortical and cortical sensorimotor areas contribute to NSS performance in healthy adults.

Imitation of meaningless gestures in normal aging

While imitation of meaningless gestures is a gold standard in the assessment of apraxia in patients with either stroke or neurodegenerative diseases, little is known about potential age-related effects on this measure. A significant body of literature has indicated that different mechanisms (i.e., executive functioning, visuospatial skills, sensory integration, body knowledge, categorical apprehension) may underlie the performance depending on imitation conditions (i.e., finger/hand, uni-/bimanual, symmetric/asymmetric, crossed/uncrossed configurations). However, neither the effects of these conditions on performance, nor the contribution of the abovementioned mechanisms to imitation have been explored in normal aging. The aim of the present study was to fill this gap. To do so, healthy adults (n = 103) aged 50 to 89 were asked to imitate 45 meaningless gestures. The authors controlled for general cognitive function, motor function, visual-spatial skills, executive function, sensory integration, body knowledge, and mechanical problem-solving skills. The results showed that asymmetry, body-midline crossing and, to a lesser extent, bimanual activity added an additional layer of difficulty to imitation tasks. After controlling for motor speed and cognitive function, age had an effect on imitation skills after 70 years old. This may reflect a decline in body knowledge, sensory integration, and executive functions. In contrast, the visuospatial and mechanical problem-solving hypotheses were ruled out. An additional motor simulation hypothesis is proposed. These findings may prove useful for clinicians working in memory clinics by providing insights on how to interpret imitation deficits. Lower performance after 70 years old should not be considered abnormal in a systematic manner.

Neurological soft signs (NSS) and cognitive impairment in chronic schizophrenia

Recent studies indicate that neurological soft signs (NSS) in schizophrenia are associated with generalized cognitive impairments rather than changes in specific neuropsychological domains. However, the majority of studies solely included first-episode patients or patients with a remitting course and did not consider age, course, education or severity of global cognitive deficits as potential confounding variables. Therefore, we examined NSS with respect to cognitive deficits in chronic schizophrenia, i.e. patients who are particularly vulnerable to both, NSS and cognitive impairments.

Eighty patients with chronic schizophrenia (43.36 ± 15a) and 60 healthy controls (47.52 ± 14.8a) matched for age, sex and years of education were examined on the Heidelberg NSS scale and a broad neuropsychological battery including short term, working, logical and autobiographic memory (AM), theory of mind (ToM), psychomotor speed and cognitive flexibility.

When contrasted with the controls, patients showed significantly higher NSS scores and impairments in all neuropsychological domains but short-term memory. NSS were significantly associated with all neuropsychological domains considered but short-term memory and semantic AM. Except for episodic AM (which was significantly correlated with NSS in patients only) these correlations applied to both groups and were confirmed when age, years of education and severity of global cognitive deficits (Mini Mental State Examination) were controlled for.

Results demonstrate that NSS reflect a rather wide range of cognitive impairments in schizophrenia, which also involves episodic AM and ToM. These associations were not accounted for by age, education or severity of global cognitive deficits and facilitate the clinical usage of NSS as a screening instrument.

Neurological soft signs as a marker of cognitive impairment severity in people living with HIV

HIV-associated neurocognitive disorders (HAND) include asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND) and HIV-associated dementia. Early recognition of HAND is crucial, and usually requires thorough neuropsychological testing. Neurological soft signs (NSS), i.e. minor motor and sensory changes, a common feature in severe psychiatric disorders, may facilitate early diagnosis. NSS were examined using the Heidelberg NSS Scale in 18 patients with ANI, 21 with MND, 28 HIV positive patients without HAND, and 39 healthy controls matched for age, gender, and education. The highest NSS scores were obtained in the MND patients (13.3 ± 10.0, p < 0.0001) followed by those with ANI (11.7 ± 10.6), the HIV positive subjects without neurocognitive deficits (8.0 ± 4.1) and the healthy controls (3.8 ± 3.2). This result was confirmed when age and years of school education were entered as covariates. No significant correlations between NSS and CD4 counts or any other clinical variables were found among the HIV positive groups. Our results demonstrate that NSS are frequently found in both ANI and MND but not HIV positive patients without neurocognitive deficits. NSS may facilitate the screening of HIV positive patients for ANI and MND as an easier and less expensive clinical tool.

Neurological Soft Signs and Psychopathology in Chronic Schizophrenia: A Cross-Sectional Study in Three Age Groups

As established in a wealth of studies subtle motor and sensory neurological abnormalities or neurological soft signs (NSS) are frequently found in patients with schizophrenia at any stage of their illness. However, the potential impact of chronicity and age on NSS was scarcely investigated. Therefore, we assessed NSS in 90 patients with subchronic (n = 22) or chronic (n = 68) schizophrenia and in 60 healthy controls who were assigned to three age groups (18-29, 30-49, and +50 years). NSS were measured on the Heidelberg Scale, psychopathological symptoms including apathy were rated on established instruments. As demonstrated by analysis of variance, NSS scores in patients were significantly (p < 0.05) increased relative to healthy controls. Significant age effects arose in all NSS subscores, with older subjects scoring well above the younger ones. These age effects were more pronounced in patients than controls, indicating that NSS in chronic schizophrenia exceed age-associated changes. Moreover, the NSS scores in patients were significantly associated with duration of illness, thought disturbance, positive symptoms, and apathy. These results were confirmed after age/duration of illness and years of education were partialed out and via regression analyses. Our findings conform to the hypothesis that NSS are associated with chronicity of the disorder as indicated by the correlations of NSS with both, duration of illness and apathy. The correlations between NSS and positive symptoms/thought disturbance correspond to the fluctuation of positive symptoms during the course of the disorder. The significantly more pronounced age effects on NSS in patients may either point to ongoing cerebral changes or to a greater susceptibility of patients toward physiological age effects, which may be mediated among other factors by a lower cognitive reserve.

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.

Proposing the short Neurological Evaluation Scale

OBJECTIVES

The time required in completing the 26 items of neurological examinations in the standard Neurological Evaluation Scale (NES) may limit its utility in pragmatic clinical situations. We propose the Short Neurological Evaluation Scale (S-NES) for use in busy clinical settings, and in research.

METHODS

Using confirmatory factor analyses, we identified 12 items of neurological examination showing significant overlap with previously reported theoretical and empirical categories of neurological soft signs (NSS) in schizophrenia. This provided justification for the development of a shorter version of the NES based on the empirically identified NSS. In the present study, we relied on existing data to present an initial validation of the S-NES against the referent standard 26-item NES. We determined sensitivity, specificity, and likelihood ratios. Posterior-test probability was estimated using a Bayesian nomogram plot.

RESULTS

Using data derived from 84 unmedicated or minimally treated patients with first-episode schizophrenia, 12 empirically determined items of neurological examinations showed high agreement with the 26 items in the standard NES battery (sensitivity=96.3%, specificity=100%, and posterior-test probability=100%).

CONCLUSIONS

Within limitations of validity estimates derived from existing data, the present results suggest that the design of the S-NES based on empirically identified 12 items of neurological examination is a logical step. If successful, the S-NES will be useful for rapid screening of NSS in busy clinical settings, and also in research.

Neurological soft signs: Effects of trait schizotypy, psychological distress and auditory hallucination predisposition

Schizotypy is regarded as a trait vulnerability for psychotic disorders, yet alone is insufficient for development of a diagnosable disorder. Additional symptoms and psychological distress are necessary for help seeking and transition from an at risk mental state to a clinical diagnosis. The present study investigated the interaction between trait schizotypy, state auditory verbal hallucination (AVH) predisposition, distress and handedness for the expression of neurological soft signs (NSS), a neurodevelopmental vulnerability factor for psychosis. Cluster analysis formed schizotypy groups statistically across the dimensions captured by the SPQ. It was hypothesized that schizotypy and AVH predisposition would interact, resulting in significantly greater NSS. Psychological distress and handedness were hypothesized to be significant covariates, accounting for some variance in the expression of NSS between the groups. A sample of University students (n = 327) completed the Schizotypal Personality Questionnaire, Launay-Slade Hallucination Scale, General Health Questionnaire and the Neurological Evaluation Scale (NES). Cluster Analysis revealed four schizotypy groups. Distress was not a significant covariate in any analysis. As expected, those with high overall schizotypy and high AVH predisposition expressed significantly greater Motor-Coordination NSS compared to those with high schizotypy and low AVH predisposition. Within the Mixed Interpersonal and Cognitive-Perceptual Schizotypy cluster, those with low AVH predisposition expressed significantly more Motor-Coordination NSS than those with high AVH predisposition. These findings suggest motor coordination NSS are detectable in schizotypy, and AVH predisposition appears to interact with these traits. This study highlights the importance of considering both trait and subclinical state risk factors when investigating risk for psychosis.

Clinical Utility and Lifespan Profiling of Neurological Soft Signs in Schizophrenia Spectrum Disorders

Neurological soft signs (NSSs) bear the promise for early detection of schizophrenia spectrum disorders. Nonetheless, the sensitivity and specificity of NSSs in the psychosis continuum remains a topic of controversy. It is also unknown how NSSs reveal neurodevelopmental abnormality in schizophrenia. We investigated the effect sizes of NSSs in differentiating individuals with schizophrenia spectrum disorders from individuals with other psychiatric conditions and from covariate-matched healthy subjects. We also investigated the partitioned age-related variations of NSSs in both schizophrenia and healthy individuals. NSSs were assessed by the abridged version of the Cambridge Neurological Inventory (CNI) in 3105 participants, consisting of healthy individuals (n=1577), unaffected first-degree relatives of schizophrenia patients (n= 155), individuals with schizotypal personality disorder (n= 256), schizophrenia patients (n= 738), and other psychiatric patients (n= 379). Exact matching and propensity score matching procedures were performed to control for covariates. Multiple regression was used to partition age-related variations. Individuals along the schizophrenia continuum showed elevated levels of NSSs, with moderate effect sizes, in contrast to other psychiatric patients who had minimal NSSs, as well as matched healthy controls. Furthermore, the age-and-NSS relationship in schizophrenia patients was represented by a flat but overall elevated pattern, in contrast to a U-shaped pattern in healthy individuals. In sum, NSSs capture a moderate portion of psychosis proneness with reasonable specificity. Lifespan profiling reveals an abnormal developmental trajectory of NSSs in schizophrenia patients, which supports the endophenotype hypothesis of NSSs by associating it with the neurodevelopmental model of schizophrenia.

[Minimal cerebral dysfunctions and ADHD in adulthood]

Attention deficit hyperactivity disorder (ADHD) is of great importance not only in children but also in adults; however, despite extensive research there are still many unsolved questions with respect to the diagnosis. Patients not only suffer from attention deficits and hyperactivity but also a variety of other problems, such as dyspraxia, problems with stimulus discrimination, dysgrammatism, legasthenia, or motor coordination problems. Furthermore, there are also psychopathological disorders, such as problems with memory, formal thinking, emotional modulation, drive and vegetative stability, in the sense of a psycho-organic syndrome. Such syndromes have long been known in psychiatry under terms, such as complex capacity disorders, minimal cerebral dysfunction (MCD), minimal brain dysfunction (MBD), mild psycho-organic syndrome, psycho-organic axis syndrome, mild cognitive impairment, developmental disorder and developmental biological syndrome. Etiological data with respect to genetics and early childhood brain trauma support the notion of a psychobiological disorder for complex cerebral dysfunction in the sense of a psycho-organic syndrome. Depending on the individual life and work situation, these additional symptoms of ADHD are in many cases of greater relevance for life adjustment than the core symptoms, depending on the individual life and work situations. The concept of minimal cerebral dysfunction describes the ADHD problem better and has a direct bearing on the diagnosis, therapy and sociomedical care of the patients.