A new approach to identifying the effect of diabetic peripheral neuropathy on the ability to drive safely

© 2020 The Authors The purpose of this study was to estimate the potential for impaired driving performance in current drivers with diabetic peripheral neuropathy compared to healthy controls. We analysed, using a driving simulator, three important aspects of driving - use of the accelerator pedal, steering wheel and eye-steering coordination - to test for any differences, and then to integrate these findings to identify a unique pattern of changes in people driving with diabetic peripheral neuropathy. Patients with diabetic peripheral neuropathy displayed differences in use of the accelerator pedal compared to healthy control drivers (p < 0.05) which could be a direct consequence of their sensorimotor impairment due to diabetic peripheral neuropathy. Drivers with DPN used the more extreme high and low positions of the pedal to a greater extent than the Control group who exhibited a more graded use of the accelerator pedal over the mid-range. Eye-steering coordination was also different in drivers with diabetic peripheral neuropathy (p < 0.05) and, as it improved during the second drive, becoming closer to healthy drivers’ values, the occasional loss of control experienced during driving reduced. These insights demonstrate that diabetic peripheral neuropathy affects multiple aspects of driving performance suggesting the need for an integrated approach to evaluate the potential for driving safely in this population

Altered accelerator pedal control in a driving simulator in people with diabetic peripheral neuropathy.

AIM:To investigate whether the sensory-motor impairment attributable to diabetic peripheral neuropathy would affect control of the accelerator pedal during a driving simulator task. METHODS:A total of 32 active drivers, 11 with diabetic peripheral neuropathy (mean ± sd age 67±5.0 years), 10 with diabetes but no neuropathy (diabetes group; mean ± sd age 62±10 years), and 11 healthy individuals without diabetes (healthy group; mean ± sd age 60±11 years), undertook a test on a dynamometer to assess ankle plantar flexor muscle strength and ankle joint proprioception function of the right leg, in addition to a driving simulator task. The following variables were measured: maximal ankle plantar flexor muscle strength; speed of strength generation (Nm/s); and ankle joint proprioception (ankle repositioning error, degrees). In the driving simulator task, driving speed (mph), accelerator pedal signal (degrees) and the duration of specific 'loss-of-control events' (s) were measured during two drives (Drive 1, Drive 2). RESULTS:Participants with diabetic peripheral neuropathy had a lower speed of strength generation (P<0.001), lower maximal ankle plantar flexor muscle strength (P<0.001) and impaired ankle proprioception (P=0.034) compared to healthy participants. The diabetic peripheral neuropathy group drove more slowly compared with the healthy group (Drive 1 P=0.048; Drive 2 P=0.042) and showed marked differences in the use of the accelerator pedal compared to both the diabetes group (P=0.010) and the healthy group (P=0.002). Participants with diabetic peripheral neuropathy had the longest duration of loss-of-control events, but after one drive, this was greatly reduced (P=0.023). CONCLUSIONS:Muscle function, ankle proprioception and accelerator pedal control are all affected in people with diabetic peripheral neuropathy, adversely influencing driving performance, but potential for improvement with targeted practice remains possible. This article is protected by copyright. All rights reserved

Combined exercise and visual gaze training improves stepping accuracy in people with diabetic peripheral neuropathy

Publisher's version (útgefin grein)Introduction: Patients with diabetes and diabetic peripheral neuropathy (DPN) place their feet with less accuracy whilst walking, which may contribute to the increased falls-risk. This study examines the effects of a multi-faceted intervention on stepping accuracy, in patients with diabetes and DPN. Methods: Forty participants began the study, of which 29 completed both the pre and post-intervention tests, 8 patients with DPN, 11 patients with diabetes but no neuropathy (D) and 10 healthy controls (C). Accuracy of stepping was measured pre- and post-intervention as participants walked along an irregularly arranged stepping walkway. Participants attended a one-hour session, once a week, for sixteen weeks, involving high-load resistance exercise and visual-motor training. Results: Patients who took part in the intervention improved stepping accuracy (DPN: +45%; D: +36%) (p < 0.05). The diabetic non-intervention (D-NI) group did not display any significant differences in stepping accuracy pre- to post- the intervention period (−7%). Discussion: The improved stepping accuracy observed in patients with diabetes and DPN as a result of this novel intervention, may contribute towards reducing falls-risk. This multi-faceted intervention presents promise for improving the general mobility and safety of patients during walking and could be considered for inclusion as part of clinical treatment programmes.This work was supported by a Clinical Research Grant from the European Foundation for the Study of Diabetes (EFSD).Peer Reviewe

Behavioural Significance of Cerebellar Modules

A key organisational feature of the cerebellum is its division into a series of cerebellar modules. Each module is defined by its climbing input originating from a well-defined region of the inferior olive, which targets one or more longitudinal zones of Purkinje cells within the cerebellar cortex. In turn, Purkinje cells within each zone project to specific regions of the cerebellar and vestibular nuclei. While much is known about the neuronal wiring of individual cerebellar modules, their behavioural significance remains poorly understood. Here, we briefly review some recent data on the functional role of three different cerebellar modules: the vermal A module, the paravermal C2 module and the lateral D2 module. The available evidence suggests that these modules have some differences in function: the A module is concerned with balance and the postural base for voluntary movements, the C2 module is concerned more with limb control and the D2 module is involved in predicting target motion in visually guided movements. However, these are not likely to be the only functions of these modules and the A and C2 modules are also both concerned with eye and head movements, suggesting that individual cerebellar modules do not necessarily have distinct functions in motor control

Neuroanatomical Circuitry Associated with Exploratory Eye Movement in Schizophrenia: A Voxel-Based Morphometric Study

Schizophrenic patients present abnormalities in a variety of eye movement tasks. Exploratory eye movement (EEM) dysfunction appears to be particularly specific to schizophrenia. However, the underlying mechanisms of EEM dysfunction in schizophrenia are not clearly understood. To assess the potential neuroanatomical substrates of EEM, we recorded EEM performance and conducted a voxel-based morphometric analysis of gray matter in 33 schizophrenic patients and 29 well matched healthy controls. In schizophrenic patients, decreased responsive search score (RSS) and widespread gray matter density (GMD) reductions were observed. Moreover, the RSS was positively correlated with GMD in distributed brain regions in schizophrenic patients. Furthermore, in schizophrenic patients, some brain regions with neuroanatomical deficits overlapped with some ones associated with RSS. These brain regions constituted an occipito-tempro-frontal circuitry involved in visual information processing and eye movement control, including the left calcarine cortex [Brodmann area (BA) 17], the left cuneus (BA 18), the left superior occipital cortex (BA 18/19), the left superior frontal gyrus (BA 6), the left cerebellum, the right lingual cortex (BA 17/18), the right middle occipital cortex (BA19), the right inferior temporal cortex (BA 37), the right dorsolateral prefrontal cortex (BA 46) and bilateral precentral gyri (BA 6) extending to the frontal eye fields (FEF, BA 8). To our knowledge, we firstly reported empirical evidence that gray matter loss in the occipito-tempro-frontal neuroanatomical circuitry of visual processing system was associated with EEM performance in schizophrenia, which may be helpful for the future effort to reveal the underlying neural mechanisms for EEM disturbances in schizophrenia

Electrophysiological Characterization of The Cerebellum in the Arterially Perfused Hindbrain and Upper Body of The Rat

In the present study, a non-pulsatile arterially perfused hindbrain and upper body rat preparation is described which is an extension of the brainstem preparation reported by Potts et al., (Brain Res Bull 53(1):59–67), 1. The modified in situ preparation allows study of cerebellar function whilst preserving the integrity of many of its interconnections with the brainstem, upper spinal cord and the peripheral nervous system of the head and forelimbs. Evoked mossy fibre, climbing fibre and parallel fibre field potentials and EMG activity elicited in forelimb biceps muscle by interpositus stimulation provided evidence that both cerebellar inputs and outputs remain operational in this preparation. Similarly, the spontaneous and evoked single unit activity of Purkinje cells, putative Golgi cells, molecular interneurones and cerebellar nuclear neurones was similar to activity patterns reported in vivo. The advantages of the preparation include the ability to record, without the complications of anaesthesia, stabile single unit activity for extended periods (3 h or more), from regions of the rat cerebellum that are difficult to access in vivo. The preparation should therefore be a useful adjunct to in vitro and in vivo studies of neural circuits underlying cerebellar contributions to movement control and motor learning

Visuomotor Cerebellum in Human and Nonhuman Primates

In this paper, we will review the anatomical components of the visuomotor cerebellum in human and, where possible, in non-human primates and discuss their function in relation to those of extracerebellar visuomotor regions with which they are connected. The floccular lobe, the dorsal paraflocculus, the oculomotor vermis, the uvula–nodulus, and the ansiform lobule are more or less independent components of the visuomotor cerebellum that are involved in different corticocerebellar and/or brain stem olivocerebellar loops. The floccular lobe and the oculomotor vermis share different mossy fiber inputs from the brain stem; the dorsal paraflocculus and the ansiform lobule receive corticopontine mossy fibers from postrolandic visual areas and the frontal eye fields, respectively. Of the visuomotor functions of the cerebellum, the vestibulo-ocular reflex is controlled by the floccular lobe; saccadic eye movements are controlled by the oculomotor vermis and ansiform lobule, while control of smooth pursuit involves all these cerebellar visuomotor regions. Functional imaging studies in humans further emphasize cerebellar involvement in visual reflexive eye movements and are discussed

Illness beliefs and psychological outcomes in people experiencing psychosis

Literature review A systematic narrative review was undertaken to examine the link between illness beliefs about psychosis and distress from a critical standpoint. Three databases were searched and nineteen studies selected for review. Reviewed studies assessed links between illness beliefs in psychosis and distress, including low mood, anxiety, suicidality, quality of life and ‘recovery’. More negative illness beliefs were consistently associated with distress. Perceived entrapment by psychosis and loss of autonomy were strongly related to low mood, and perceived self-blame, stigma, shame and social status loss were strongly related to anxiety and social anxiety. Perceived consequences were strongly related to low mood, heightened anxiety, and increased suicidal ideation, and fewer perceived consequences were linked with better quality of life. Findings are discussed in relation to the self-regulation model and social ranking theory. Further longitudinal and qualitative research is needed to infer causality. Empirical research project There is a paucity of research into the causal beliefs of people experiencing psychosis and how these relate to psychological outcomes. Three-hundred-and-one participants diagnosed with ‘schizophrenia-related disorders’ completed a battery of assessments relating to causal beliefs, distress (anxiety, mood, self-esteem, unusual experiences) and other illness beliefs. A series of hierarchical regressions were performed using causal beliefs as predictors and distress and illness belief variables as criterion variables, whilst controlling for the impact of demographic variables. Causes relating to the self (e.g. ‘personality’) predicted worse distress, unusual experiences and illness beliefs. The causal belief ‘stress’ predicted worse self-esteem, and less frequent/distressing hallucinations (auditory and non-auditory). ‘Contamination’ beliefs predicted more frequent/distressing auditory hallucinations and perceptions of shorter timeline. Future research should include populations with unusual experiences who do not access mental health services. Causal beliefs should be explored sensitively and collaboratively between service users and healthcare professionals.</p