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Primary lateral sclerosis: consensus diagnostic criteria
<jats:p>Primary lateral sclerosis (PLS) is a neurodegenerative disorder of the adult motor system. Characterised by a slowly progressive upper motor neuron syndrome, the diagnosis is clinical, after exclusion of structural, neurodegenerative and metabolic mimics. Differentiation of PLS from upper motor neuron-predominant forms of amyotrophic lateral sclerosis remains a significant challenge in the early symptomatic phase of both disorders, with ongoing debate as to whether they form a clinical and histopathological continuum. Current diagnostic criteria for PLS may be a barrier to therapeutic development, requiring long delays between symptom onset and formal diagnosis. While new technologies sensitive to both upper and lower motor neuron involvement may ultimately resolve controversies in the diagnosis of PLS, we present updated consensus diagnostic criteria with the aim of reducing diagnostic delay, optimising therapeutic trial design and catalysing the development of disease-modifying therapy.</jats:p>
Joint modelling of diffusion MRI and microscopy
<jats:title>Abstract</jats:title><jats:p>The combination of diffusion MRI with microscopy provides unique opportunities to study microstructural features of tissue, particularly when acquired in the same sample. Microscopy is frequently used to validate diffusion MRI microstructure models, addressing the indirect nature of dMRI signals. Typically, these modalities are analysed separately, and microscopy is taken as a gold standard against which dMRI-derived parameters are validated. Here we propose an alternative approach in which we combine diffusion MRI and microscopy data obtained from the same tissue sample to drive a single, joint model. This simultaneous analysis allows us to take advantage of the breadth of information provided by complementary data acquired from different modalities. By applying this framework to a spherical-deconvolution analysis, we are able to overcome a known degeneracy between fibre dispersion and radial diffusion. Spherical-deconvolution based approaches typically estimate a global fibre response function to determine the fibre orientation distribution in each voxel. However, the assumption of a ‘brain-wide’ fibre response function may be challenged if the diffusion characteristics of white matter vary across the brain. Using a generative joint dMRI-histology model, we demonstrate that the fibre response function is dependent on local anatomy, and that current spherical-deconvolution based models may be overestimating dispersion and underestimating the number of distinct fibre populations per voxel.</jats:p>
Time trends, frequency, characteristics and prognosis of short-duration transient global amnesia.
BACKGROUND:Transient global amnesia (TGA) is characterised by a sudden onset of anterograde amnesia lasting up to 24 hours. One major differential for TGA is transient epileptic amnesia (TEA), which typically lasts<1h. However TGA can also be short in duration and little is known about the time-trends, characteristics and prognosis of TGA cases lasting<1h. METHODS:We compared the clinical features of TGA ascertained in two independent cohort studies in Oxfordshire, UK (Oxford cohort 1977-1987 vs. Oxford Vascular Study- OXVASC 2002-2018) to determine the time-trends of clinical features of TGA. Results were validated in another independent contemporary TGA cohort in Italy (Northern Umbria registry-NU 2002-2018). We compared the risk factors, clinical features and long-term prognosis (major cardiovascular events-MaCE, recurrent TGA and seizure/epilepsy) of patients presenting with episodes lasting <1h vs. those ≥1h. RESULTS:Overall 639 TGA patients were included (114 Oxford cohort, 100 OXVASC, 425 NU). Compared to the original Oxford cohort, there were more cases with TGA lasting <1 hour in OXVASC (n/% 32/32.0% vs. 9/8.8%), and in NU (11.8% vs 8.8% in Oxford cohort). In both OXVASC and NU, patient age, vascular risk factors and clinical features were largely comparable between those with TGA<1h vs. those lasting ≥1h. Moreover, there was no difference in the long-term risk of seizure/epilepsy or MaCE between TGA<1h vs. TGA≥1h. CONCLUSIONS:Short-duration TGA episodes (<1h) are not uncommon and are more frequent now than in earlier studies. The clinical features and long-term prognosis of short-duration TGA did not differ from more typical episodes lasting≥1h.
Perception Loss detection
The present invention relates to a device for detecting a state of true perception loss of a human, the device including processing means operable to detect from information on electrical signals sensed adjacent to the scalp of the human the activity of oscillations present in the electrical signals as a marker for the state of true perception loss of the human.
Refining prediction of major bleeding on antiplatelet treatment after transient ischaemic attack or ischaemic stroke
© European Stroke Organisation 2020. Introduction: Bleeding is the main safety concern of treatment with antiplatelet drugs. We aimed to refine prediction of major bleeding on antiplatelet treatment after a transient ischaemic attack (TIA) or stroke by assessing the added value of new predictors to the existing S2TOP-BLEED score. Patients and methods: We used Cox regression analysis to study the association between candidate predictors and major bleeding among 2072 patients with a transient ischaemic attack or ischaemic stroke included in a population-based study (Oxford Vascular Study – OXVASC). An updated model was proposed and validated in 1094 patients with a myocardial infarction included in OXVASC. Models were compared with c-statistics, calibration plots, and net reclassification improvement. Results: Independent predictors for major bleeding on top of S2TOP-BLEED variables were peptic ulcer (hazard ratio (HR): 1.72; 1.04–2.86), cancer (HR: 2.40; 1.57–3.68), anaemia (HR: 1.55; 0.99–2.44) and renal failure (HR: 2.20; 1.57–4.28). Addition of those variables improved discrimination from 0.69 (0.64–0.73) to 0.73 (0.69–0.78) in the TIA/stroke cohort (p = 0.01). Performance improved particularly for upper gastro-intestinal bleeds (0.70; 0.64–0.75 to 0.77; 0.72–0.82). Net reclassification improved over the entire range of the score (net reclassification improvement: 0.56; 0.36–0.76). In the validation cohort, discriminatory performance improved from 0.68 (0.62–0.74) to 0.70 (0.64–0.76). Discussion and Conclusion: Peptic ulcer, cancer, anaemia and renal failure improve predictive performance of the S2TOP-BLEED score for major bleeding after stroke. Future external validation studies will be required to confirm the value of the STOP-BLEED+ score in transient ischaemic attack/stroke patients.
Circuits, Networks, and Neuropsychiatric Disease: Transitioning From Anatomy to Imaging.
Since the development of cellular and myelin stains, anatomy has formed the foundation for understanding circuitry in the human brain. However, recent functional and structural studies using magnetic resonance imaging have taken the lead in this endeavor. These innovative and noninvasive approaches have the advantage of studying connectivity patterns under different conditions directly in the human brain. They demonstrate dynamic and structural changes within and across networks linked to normal function and to a wide range of psychiatric illnesses. However, these indirect methods are unable to link networks to the hardwiring that underlies them. In contrast, anatomic invasive experimental studies can. Following a brief review of prefrontal cortical, anterior cingulate, and striatal connections and the different methodologies used, this article discusses how data from anatomic studies can help inform how hardwired connections are linked to the functional and structural networks identified in imaging studies.
Modulation of the pupillary response by the content of visual working memory.
Studies of selective attention during perception have revealed modulation of the pupillary response according to the brightness of task-relevant (attended) vs. -irrelevant (unattended) stimuli within a visual display. As a strong test of top-down modulation of the pupil response by selective attention, we asked whether changes in pupil diameter follow internal shifts of attention to memoranda of visual stimuli of different brightness maintained in working memory, in the absence of any visual stimulation. Across 3 studies, we reveal dilation of the pupil when participants orient attention to the memorandum of a dark grating relative to that of a bright grating. The effect occurs even when the attention-orienting cue is independent of stimulus brightness, and even when stimulus brightness is merely incidental and not required for the working-memory task of judging stimulus orientation. Furthermore, relative dilation and constriction of the pupil occurred dynamically and followed the changing temporal expectation that 1 or the other stimulus would be probed across the retention delay. The results provide surprising and consistent evidence that pupil responses are under top-down control by cognitive factors, even when there is no direct adaptive gain for such modulation, since no visual stimuli were presented or anticipated. The results also strengthen the view of sensory recruitment during working memory, suggesting even activation of sensory receptors. The thought-provoking corollary to our findings is that the pupils provide a reliable measure of what is in the focus of mind, thus giving a different meaning to old proverbs about the eyes being a window to the mind.
Distinct influence of different vascular risk factors on white matter brain lesions in multiple sclerosis.
OBJECTIVE: To determine if vascular risk factor (VRF), that is, smoking, arterial hypertension (HT), dyslipidaemia and diabetes, have an effect on multiple sclerosis (MS) pathology as measured by MS typical brain lesions, we have compared brain MRIs from patients with MS with and without VRF age-matched and sex-matched. METHODS: Brain MRIs from five centres were scored for the presence of Dawson's fingers (DF) and juxtacortical lesions (JCL). A regression model was built to predict the effect of each individual VRF on DF and JCL, considering age and disease duration. RESULTS: 92 MS cases without VRF and 106 MS with one or more VRF (80 ever-smokers, 43 hypertensives, 25 dyslipidaemics and 10 diabetics) were included. Ever-smoking associated with a higher burden of DF (Exp(B)=1.29, 95% CI 1.10 to 1.51, p<0.01) and JCL (Exp(B)=1.38, 95% CI 1.21 to 1.57, p<0.01). No other VRF had an impact on DF. Dyslipidaemia associated with increased JCL (Exp(B)=1.30, 95% CI 1.10 to 1.56, p<0.01) but HT did not associate with any of the outcomes. CONCLUSIONS: Individual VRF appear to affect MS-specific lesions differently. An increase in MS lesions was mainly seen in smokers; however, this VRF is most likely to be present from onset of MS, and other VRF effects may be partly mitigated by treatment. Our findings support that treating VRF and cessation of smoking may be important in the management of MS.
The clinical profile of NMOSD in Australia and New Zealand.
Neuromyelitis optica spectrum disorders (NMOSD) are an inflammation of the central nervous system associated with autoantibodies to aquaporin-4. We have undertaken a clinic-based survey of NMOSD in the Australia and New Zealand populations with the aim of characterising the clinical features and establishing the value of recently revised diagnostic criteria. Cases of possible NMOSD and age and sex-matched controls with multiple sclerosis (MS) were referred from centres across Australia and New Zealand. Cases were classified as NMOSD if they met the 2015 IPND criteria and remained as suspected NMOSD if they did not. Clinical and paraclinical data were compared across the three groups. NMOSD was confirmed in 75 cases and 89 had suspected NMOSD. There were 101 controls with MS. Age at onset, relapse rates and EDSS scores were significantly higher in NMOSD than in MS. Lesions and symptoms referable to the optic nerve were more common in NMOSD whereas brainstem, cerebellar and cerebral lesions were more common in MS. Longitudinally extensive spinal cord lesions were seen in 48/71 (68%) of cases with NMOSD. Elevations of CSF, white cell count and protein were more common in NMOSD. We have confirmed a clinical pattern of NMOSD that has been seen in several geographical regions. We have demonstrated the clinical utility of the current diagnostic criteria. Distinct patterns of disease are evident in NMOSD and MS, but there remains a large number of patients with NMOSD-like features who do not meet the current diagnostic criteria for NMOSD and remain a diagnostic challenge.
Effects of Home-Based Working Memory Training on Visuo-Spatial Working Memory in Parkinson's Disease: A Randomized Controlled Trial.
Background: Cognitive impairment is a very frequent and severe nonmotor symptom of Parkinson's disease (PD). Early intervention in this at-risk group for cognitive decline may be crucial for long-term preservation of cognitive functions. Computerized working memory training (WMT) has been proven beneficial in non-PD patient populations, but such evidence is still needed for patients with PD. Objective: This study aimed to evaluate the effect of WMT on visuo-spatial working memory (WM) in cognitively unimpaired patients with PD. Methods: A single-blind randomized controlled trial encompassing 76 patients with PD but no cognitive impairment according to level II diagnostic criteria was conducted. Thirty-seven patients engaged in home-based adaptive WMT 5 times per week for a period of 5 weeks, whereas the remaining patients were in the waiting list arm of the study (control group [CG]). Working memory performance was evaluated using a computerized task before and after intervention and at 14-week follow-up, allowing to quantify the precision of WM on a continuous scale, ie, to test not only if an item was remembered but also how well the location of this item was retained. Results: Coincidently, the WMT group showed slightly worse WM performance compared with the CG at baseline, which was ameliorated after WMT. This training-induced effect remained stable until follow-up. Conclusion: Patients showing relatively low WM performance, despite not formally diagnosable as Parkinson's disease with mild cognitive impairment (PD-MCI), seem to benefit from home-based WMT. Thus, WMT could potentially be implemented in future trials as a time- and cost-efficient route to counteract subtle cognitive changes in early disease stages. Trial registration: German Clinical Trial Register (drks.de, DRKS00009379).