Cognitive dysfunction after isolated brain stem insult. An underdiagnosed cause of long term morbidity

Association of Cerebral Hypoperfusion and Poor Collaterals with Cognitive Impairment in Patients with Severe Vertebrobasilar Artery Stenosis

Background

Effect of stenosis of vertebrobasilar artery (VBA) on cognitive function is elusive.

Objective

To investigate association of cerebral hypoperfusion and poor collaterals with vascular cognitive impairment (VCI) in severe VBA stenosis patients.

Methods

We consecutively enrolled patients with severe VBA stenosis confirmed by digital subtraction angiography who underwent computed tomographic perfusion (CTP) and cognitive assessments. Patients were divided into poor or good collaterals groups according to the collateral circulation status, and were grouped into different perfusion groups according to CTP. Cognitive function was measured by Montreal Cognitive Assessment (MoCA), Clock Drawing Test, Stroop Color Word Test, Trail Making Test, Digital Span Test, Auditory Verbal Learning Test, and Boston Naming Test scales. The association of cerebral perfusion and collaterals with VCI were explored.

Results

Among 88 eligible patients, VCI occurred in 51 (57.9%) patients experienced. Poor collateral was present in 73 (83.0%) patients, and hypoperfusion in 64 (72.7%). Compared with normal perfusion patients, the odds ratio with 95% confidence interval for VCI was 12.5 (3.7-42.4) for overall hypoperfusion, 31.0 (7.1-135.5) for multiple site hypoperfusion, 3.3 (1.0-10.5) for poor collaterals, and 0.1 (0-0.6) for presence of posterior communicating artery (PcoA) compensated for posterior cerebral artery (PCA) and basilar artery (BA). Additionally, decreased scores of cognitive function tests occurred in patients with decompensated perfusion or poor collaterals.

Conclusions

Hypoperfusion and poor collaterals were positively associated with cognitive impairment in patients with severe VBA. However, PcoA compensated for the PCA and BA had a protective role in cognitive impairment development.

Profiling Daily Life Performance Recovery in the Early Subacute Phase After Stroke Using a Graphical Modeling Approach

Background Laboratory-based assessments have shown that stroke recovery is heterogeneous between patients and affected domains such as motor and language function. However, laboratory-based assessments are not ecologically valid and do not necessarily reflect patients' daily life performance. Therefore, we aimed to give an innovative view on stroke recovery by profiling daily life performance recovery across domains in patients with early subacute stroke and determine their interrelatedness, taking stroke localization into account. Methods and Results Daily life performance was observed at neurorehabilitation admission and weekly thereafter until discharge, using a scale containing 7 daily life domains. Graphical modeling was applied to investigate the conditional independence between recovery of these domains depending on stroke localization. There were 592 patients analyzed. Four clusters of interrelated domains were identified within the first 6 weeks poststroke. The first cluster included recovery in learning and applying knowledge, general tasks and demands, and domestic life. The second cluster comprised recovery in self-care and general tasks and demands. The third cluster included recovery in mobility and self-care; it incorporated interpersonal interactions and relationships in left supratentorial stroke, and learning and applying knowledge in right supratentorial stroke. The final cluster included only communication recovery. Conclusions Daily life recovery dynamics early poststroke show that although impairments in body functions are anatomically determined, their impact on performance is comparable. Second, some, but by no means all, domains show an interrelated recovery. Domains requiring cognitive abilities are especially interrelated and seem to be essential for concomitant recovery in mobility and domestic life.

Cognitive Performance in Patients With Sporadic Vestibular Schwannoma

BACKGROUND

To date, few data are available on the cognitive function of patients with vestibular schwannoma (VS) before treatment.

OBJECTIVE

To provide a cognitive profile of patients with VS.

METHODS

This cross-sectional observational study recruited 75 patients with an untreated VS and 60 age-, sex-, and education-matched healthy control subjects. A set of neuropsychological tests were administered to each participant.

RESULTS

Compared with the matched controls, patients with VS exhibited impaired general cognitive function, memory, psychomotor speed, visuospatial ability, attention and processing speed, and executive function. The subgroup analyses displayed that patients with severe-to-profound unilateral hearing loss were more cognitively impaired than patients with no-to-moderate unilateral hearing loss. In addition, patients with right-sided VS scored worse than those with left-sided VS on tests of memory, attention and processing speed, and executive function. No differences were observed in cognitive performance between patients with or without brainstem compression and those with or without tinnitus. We also found that worse hearing and longer hearing loss duration were associated with poorer cognitive performance in patients with VS.

CONCLUSION

The findings of this study provide evidence for cognitive impairment in patients with untreated VS. It can thus be said that including cognitive assessment in the routine clinical management of patients with VS may facilitate more appropriate clinical decision-making and improve patients' quality of life.

A case study of left visual neglect after right pontine lesion: pathophysiological evidence for the infratentorial involvement in human visual attention

Hemispatial neglect, the inability to attend to the contralesional side of space, is the most common disturbance of visuospatial attention. Both hemispatial neglect and visuospatial attention are typically associated with extended cortical networks. Nevertheless, recent accounts challenge this so-called corticocentric view and postulate the participation of structures well beyond the telencephalic cortex, in particular advocating the role of the brainstem. However, to the best of our knowledge, hemispatial neglect after a brainstem lesion has not yet been described. We describe, for the first time in a human, the occurrence and remission of contralesional visual hemispatial neglect after a focal lesion in the right pons. Hemispatial neglect was assessed by means of video-oculography during free visual exploration, a very sensitive and established method, and its remission was followed up until 3 wk after stroke. Moreover, by means of a lesion-deficit approach complemented by imaging, we identify a pathophysiological mechanism involving the disconnection of cortico-ponto-cerebellar and/or tecto-cerebellar-tectal pathways passing through the pons. Our findings offer, for the first time in a human, causal, lesion-based support for recent seminal accounts postulating the role of infratentorial structures participating in the activity of cerebral cortical attentional networks mediating attentional processes.NEW & NOTEWORTHY Visuospatial attention and its most common disturbance, hemispatial neglect, are typically associated with extended cortical networks. However, recent accounts challenge this corticocentric view and advocate the role of infratentorial structures. We describe, for the first time in a human, the occurrence of contralesional visual hemispatial neglect after a focal lesion in the right pons. We provide causal, lesion-based evidence for a pathophysiological mechanism involving the disconnection of cortico-ponto-cerebellar and/or tecto-cerebellar-tectal pathways passing through the pons.

Locked-in syndrome revisited

The locked-in syndrome (LiS) is characterized by quadriplegia with preserved vertical eye and eyelid movements and retained cognitive abilities. Subcategorization, aetiologies and the anatomical foundation of LiS are discussed. The damage of different structures in the pons, mesencephalon and thalamus are attributed to symptoms of classical, complete and incomplete LiS and the locked-in plus syndrome, which is characterized by additional impairments of consciousness, making the clinical distinction to other chronic disorders of consciousness at times difficult. Other differential diagnoses are cognitive motor dissociation (CMD) and akinetic mutism. Treatment options are reviewed and an early, interdisciplinary and aggressive approach, including the provision of psychological support and coping strategies is favoured. The establishment of communication is a main goal of rehabilitation. Finally, the quality of life of LiS patients and ethical implications are considered. While patients with LiS report a high quality of life and well-being, medical professionals and caregivers have largely pessimistic perceptions. The negative view on life with LiS must be overthought and the autonomy and dignity of LiS patients prioritized. Knowledge has to be disseminated, diagnostics accelerated and technical support system development promoted. More well-designed research but also more awareness of the needs of LiS patients and their perception as individual persons is needed to enable a life with LiS that is worth living.

Eye movement desensitization and reprocessing for post-stroke post-traumatic stress disorder: Case report using the three-phase approach

Medically-induced post-traumatic stress disorder (PTSD) is substantially more prevalent than PTSD in the general population. In people with stroke, it can impact as many as 23% of patients, with negative effects on mental health as well as stroke-related disability. Medically-induced PTSD may have unique features compared to other forms of PTSD, and therefore there is a pressing need to evaluate existing treatments for PTSD in this context. The current study reports on the feasibility, safety, and efficacy of Eye Movement Desensitization and Reprocessing (EMDR) for PTSD subsequent to a pontine stroke. Using a quasi-experimental case design, a 44-year-old Caucasian woman received EMDR delivered via telehealth. Self-report measures were obtained at baseline, pre-EMDR, and post-EMDR, with brief neuropsychological testing pre/post-EMDR. After 3 sessions of EMDR, the patient no longer met criteria for PTSD, and showed clinically significant reductions in depressive and generalized anxiety symptoms. With proper safety provisions, it is feasible to deliver EMDR via telehealth to alleviate post-stroke PTSD. Reduced linguistic demands of EMDR may be particularly appealing for persons with neurological disorders as compared to other trauma therapies. Further work is also needed to understand the parameters of baseline neuropsychological function that could impact response to intervention.

Defining the Role of Attention in Hierarchical Auditory Processing

Communication in noise is a complex process requiring efficient neural encoding throughout the entire auditory pathway as well as contributions from higher-order cognitive processes (i.e., attention) to extract speech cues for perception. Thus, identifying effective clinical interventions for individuals with speech-in-noise deficits relies on the disentanglement of bottom-up (sensory) and top-down (cognitive) factors to appropriately determine the area of deficit; yet, how attention may interact with early encoding of sensory inputs remains unclear. For decades, attentional theorists have attempted to address this question with cleverly designed behavioral studies, but the neural processes and interactions underlying attention's role in speech perception remain unresolved. While anatomical and electrophysiological studies have investigated the neurological structures contributing to attentional processes and revealed relevant brain-behavior relationships, recent electrophysiological techniques (i.e., simultaneous recording of brainstem and cortical responses) may provide novel insight regarding the relationship between early sensory processing and top-down attentional influences. In this article, we review relevant theories that guide our present understanding of attentional processes, discuss current electrophysiological evidence of attentional involvement in auditory processing across subcortical and cortical levels, and propose areas for future study that will inform the development of more targeted and effective clinical interventions for individuals with speech-in-noise deficits.

Plus-minus lid syndrome with ataxia and severe apathy-A rare manifestation of midbrain infarct

Plus-minus lid syndrome is a rare manifestation of midbrain infarct, characterized by ptosis of one eye and lid retraction in the other eye. It has also been described in ocular myasthenia gravis, orbital myositis, or after lesions of the oculomotor nerve. Our patient was a 55-year-old man with hypertension and atrial fibrillation, who presented to us with acute onset left-sided ptosis and right-sided eyelid retraction. He was apathic and had right-sided ataxia. His MRI of the brain showed acute infarct involving the paramedian midbrain. To our knowledge, severe apathy and resultant executive function disorder have not been described previously in a patient having plus-minus lid syndrome with ataxia.

Cerebellar structural connectivity and contributions to cognition in frontotemporal dementias

Frontotemporal dementia (FTD) is a heterogeneous group of neurodegenerative brain disorders, primarily affecting the frontal and/or temporal lobes. Three main subtypes are recognised, each with distinct clinical and cognitive profiles: behavioural-variant FTD (bvFTD), semantic dementia (SD), and progressive nonfluent aphasia (PNFA). Subtype-specific cerebellar grey matter atrophy has been associated with cognitive dysfunction in FTD; however, the extent and severity of structural abnormalities in the cerebro-cerebellar circuits in these disorders has not been investigated. This study aimed to identify patterns of cerebellar white matter changes and their relations to cognitive deficits in the main FTD subtypes. Results revealed bilateral cerebellar white matter changes in all FTD subtypes compared with controls, with greater cerebellar white matter changes in bvFTD than SD and PNFA. Both afferent and efferent cerebellar pathways were associated with cognition. The profiles of the involvement of cerebellar pathways in cognition varied across FTD syndromes. In bvFTD, the output pathway of the cerebellum was only associated with measures of episodic memory. The input pathway was associated with measures of attention, working memory, visuospatial, episodic memory, executive function, and emotion. In SD, both the output and input pathways were associated with measures of working memory, language, and emotion. Finally, in PNFA, both the output and input pathway of the cerebellum were associated with attention, language, and executive function. Additionally, the input pathway was associated with working memory, visuospatial, and emotion. This study is the first to identify patterns of cerebellar white matter changes across FTD syndromes, which in turn relate to cognitive deficits. These findings extend our understanding of the cerebro-cerebellar networks and provide new insight into the role of cerebellar white matter in cognition.

The Supplementary Motor Area Responsible for Word Retrieval Decline After Acute Thalamic Stroke Revealed by Coupled SPECT and Near-Infrared Spectroscopy

Damage to the thalamus may affect cognition and language, but the underlying mechanism remains unknown. In particular, it remains a riddle why thalamic aphasia occasionally occurs and then mostly recovers to some degree. To explore the mechanism of the affected cognition and language, we used two neuroimaging techniques—single-photon emission computed tomography (SPECT), suitable for viewing the affected brain distribution after acute thalamic stroke, and functional near-infrared spectroscopy (f-NIRS), focusing on hemodynamic responses of the supplementary motor area (SMA) responsible for speech production in conjunction with the frontal aslant tract (FAT) pathway. SPECT yielded common perfusion abnormalities not only in the fronto–parieto–cerebellar loop, but also in the SMA, IFG and surrounding language-relevant regions. In NIRS sessions during a phonemic verbal fluency task, we found significant word retrieval decline in acute thalamic patients relative to age-matched healthy volunteers. Further, NIRS showed strong correlation between word retrieval and posterior SMA responses. In addition, follow-up NIRS exhibited increased bilateral SMA responses linked to improving word retrieval ability. The findings suggest that cognitive dysfunction may be related to the fronto–parieto–cerebellar loop, while language dysfunction is attributed to the SMA, IFG and language-related brain areas. SMA may contribute to the recovery of word retrieval difficulty and aphasia after thalamic stroke.

Bihemispheric changes associated with cognition in patients with chronic brainstem stroke

OBJECTIVE

We aimed to identify brain changes associated with preserved cognitive function in patients with chronic brainstem stroke.

METHODS

Twelve patients with chronic brainstem stroke and 24 age-matched healthy controls were included in this retrospective study. All participants underwent T1-weighted, diffusion tensor, and resting-state functional MRI. Gray matter density, fractional anisotropy, and mean diffusivity maps from diffusion tensor imaging and seven cognition-related independent component maps from resting-state functional MRI were used to identify differences in brain volume, structural connectivity, and functional connectivity. Independent t-tests were used to determine the statistical significance of changes in gray matter density, fractional anisotropy, mean diffusivity, and inter-network functional connectivity maps.

RESULTS

Bilateral cerebellum volumes and structural connectivity of the diffuse bilateral cerebral hemispheres were significantly lower in the patient than in the control group. However, patients exhibited increased gray matter volume and increased structural connectivity of the temporal lobe in the contra-lesional hemisphere and basal forebrain, compared with healthy controls. Furthermore, the intra-network functional connectivity in the frontal and temporal lobes was significantly higher in patients than in controls (PFWE < 0.05).

CONCLUSION

In the patient group, the brain regions mainly associated with the cholinergic system exhibited increased volume, structural connectivity, and functional connectivity. In contrast, the regions connected with the brainstem via cortico-ponto-cerebellar fibers exhibited decreased volume or structural connectivity. Cognitive function may be preserved in patients with brainstem stroke due to significant increases in frontal and temporal inter-network connectivity.

A missing piece? Neuropsychiatric functioning in untreated patients with tumors within the cerebellopontine angle

PURPOSE

To date, little is known about neuropsychiatric symptoms in patients with tumors within the cerebellopontine angle (CPA). These, however, might be of clinical relevance. Aim of this study was thus to assess possible impairment in cognition, elevation in mood symptoms, and fatigue in this specific patient group.

METHODS

Forty-five patients with an untreated CPA tumor (27 vestibularis schwannoma, 18 meningioma) were tested within a cross-sectional observational study in a single institution prior to neurosurgical treatment. Patients were administered a multifaceted battery comprising of widely-used tests for assessment of neuropsychiatric functioning.

RESULTS

The majority of the included patients (69%) showed neurocognitive impairment, most frequently in the areas of attention and visuo-motor speed (e.g., alertness) (62%) as well as visuo-construction (44%). Impaired structural integrity of the brain stem was accompanied by more serious neurocognitive deficits. About one-third of the sample reported clinically relevant depression and/or anxiety and an even higher proportion (48%) described high levels of fatigue. Cognitive and affective symptoms as well as fatigue contributed significantly to patients' Quality of Life, indicating the clinical relevance of neuropsychiatric symptoms in patients with CPA tumors.

CONCLUSIONS

Although patients with untreated CPA tumors often suffer from devastating and prominent physical symptoms, neuropsychiatric problems are also frequent. Including these aspects in the routine clinical assessment and initiating treatment accordingly might thus improve clinical management of the patients and improve Quality of Life.

Defining mechanisms of neural plasticity after brainstem ischemia in rats

OBJECTIVE

Neurological recovery after stroke mainly depends on the location of the lesion. A substantial portion of strokes affects the brainstem. However, patterns of neural plasticity following brainstem ischemia are almost unknown.

METHODS

Here, we established a rat brainstem ischemia model that resembles key features of the human disease and investigated mechanisms of neural plasticity, including neurogenesis and axonal sprouting as well as secondary neurodegeneration.

RESULTS

Spontaneous functional recovery was accompanied by a distinct pattern of axonal sprouting, for example, an increased bilateral fiber outgrowth from the corticorubral tract to the respective contralesional red nucleus suggesting a compensatory role of extrapyramidal pathways after damage to pyramid tracts within the brainstem. Using different markers for DNA replication, we showed that the brainstem displays a remarkable ability to undergo specific plastic cellular changes after injury, highlighting a yet unknown pattern of neurogenesis. Neural progenitor cells proliferated within the dorsal brainstem and migrated toward the lesion, whereas neurogenesis in classic neurogenic niches, the subventricular zone of the lateral ventricle and the hippocampus, remained, in contrast to what is known from hemispheric stroke, unaffected. These beneficial changes were paralleled by long-term degenerative processes, that is, corticospinal fiber loss superior to the lesion, degeneration of spinal tracts, and a decreased neuron density within the ipsilesional substantia nigra and the contralesional red nucleus that might have limited further functional recovery.

INTERPRETATION

Our findings provide knowledge of elementary plastic adaptions after brainstem stroke, which is fundamental for understanding the human disease and for the development of new treatments. Ann Neurol 2018;83:1003-1015.

Arterial Spin-Labeling Perfusion MR Imaging Demonstrates Regional CBF Decrease in Idiopathic Normal Pressure Hydrocephalus

BACKGROUND AND PURPOSE

Regional cerebral blood flow has previously been studied in patients with idiopathic normal pressure hydrocephalus with imaging methods that require an intravenous contrast agent or expose the patient to ionizing radiation. The purpose of this study was to assess regional CBF in patients with idiopathic normal pressure hydrocephalus compared with healthy controls using the noninvasive quantitative arterial spin-labeling MR imaging technique. A secondary aim was to compare the correlation between symptom severity and CBF.

MATERIALS AND METHODS

Differences in regional cerebral perfusion between patients with idiopathic normal pressure hydrocephalus and healthy controls were investigated with pseudocontinuous arterial spin-labeling perfusion MR imaging. Twenty-one consecutive patients with idiopathic normal pressure hydrocephalus and 21 age- and sex-matched randomly selected healthy controls from the population registry were prospectively included. The controls did not differ from patients with respect to selected vascular risk factors. Twelve different anatomic ROIs were manually drawn on coregistered FLAIR images. The Holm-Bonferroni correction was applied to statistical analyses.

RESULTS

In patients with idiopathic normal pressure hydrocephalus, perfusion was reduced in the periventricular white matter (P < .001), lentiform nucleus (P < .001), and thalamus (P < .001) compared with controls. Cognitive function in patients correlated with CBF in the periventricular white matter (r = 0.60, P < .01), cerebellum (r = 0.63, P < .01), and pons (r = 0.71, P < .001).

CONCLUSIONS

Using pseudocontinuous arterial spin-labeling, we could confirm findings of a reduced perfusion in the periventricular white matter, basal ganglia, and thalamus in patients with idiopathic normal pressure hydrocephalus previously observed with other imaging techniques.

Peduncular psychosis

Psychotic symptoms are rarely documented in association with cortex-sparing central nervous system (CNS) lesions limited to the midbrain. We present the case of a 15-year-old boy with hereditary and environmental risk factors for psychiatric illness, as well as a history of midbrain pilocytic astrocytoma treated with chemotherapy and focused radiation, who presented with non-epileptic seizures, hyper-religiosity and frank psychosis. The space-occupying midbrain lesion has been radiographically stable while the patient has decompensated psychiatrically. Differential aetiology for the patient's psychiatric decompensation is discussed, including psychosis secondary to a lesion of the midbrain. Literature linking midbrain lesions to psychotic features, such as in peduncular hallucinosis, is briefly reviewed. This case suggests that a midbrain lesion in a susceptible patient may contribute to psychosis.

Robust Machine Learning-Based Correction on Automatic Segmentation of the Cerebellum and Brainstem

Automated segmentation is a useful method for studying large brain structures such as the cerebellum and brainstem. However, automated segmentation may lead to inaccuracy and/or undesirable boundary. The goal of the present study was to investigate whether SegAdapter, a machine learning-based method, is useful for automatically correcting large segmentation errors and disagreement in anatomical definition. We further assessed the robustness of the method in handling size of training set, differences in head coil usage, and amount of brain atrophy. High resolution T1-weighted images were acquired from 30 healthy controls scanned with either an 8-channel or 32-channel head coil. Ten patients, who suffered from brain atrophy because of fragile X-associated tremor/ataxia syndrome, were scanned using the 32-channel head coil. The initial segmentations of the cerebellum and brainstem were generated automatically using Freesurfer. Subsequently, Freesurfer's segmentations were both manually corrected to serve as the gold standard and automatically corrected by SegAdapter. Using only 5 scans in the training set, spatial overlap with manual segmentation in Dice coefficient improved significantly from 0.956 (for Freesurfer segmentation) to 0.978 (for SegAdapter-corrected segmentation) for the cerebellum and from 0.821 to 0.954 for the brainstem. Reducing the training set size to 2 scans only decreased the Dice coefficient ≤0.002 for the cerebellum and ≤ 0.005 for the brainstem compared to the use of training set size of 5 scans in corrective learning. The method was also robust in handling differences between the training set and the test set in head coil usage and the amount of brain atrophy, which reduced spatial overlap only by <0.01. These results suggest that the combination of automated segmentation and corrective learning provides a valuable method for accurate and efficient segmentation of the cerebellum and brainstem, particularly in large-scale neuroimaging studies, and potentially for segmenting other neural regions as well.

Cognitive and Functional Impairment in Stroke Survivors with Basilar Artery Occlusive Disease

Background. Despite growing literature on posterior vascular disease, specific information about the cognitive and functional profiles of patients with basilar artery occlusion disease (BAOD) is scarce. The aims of this study were (1) to compare the cognitive statuses of BAOD survivors versus healthy controls and (2) to correlate the functional capacity outcomes with the cognitive profiles of BAOD patients. Methods. Comprehensive cognitive and functional assessments were carried out in 28 patients with BAOD and 27 age- and education level-matched healthy controls. Results. Compared to matched controls, patients presented impairments in selective, sustained, and set-shifting attention, processing speed, visuospatial skills, mental flexibility, and monitoring rules. There were significant deficits in verbal episodic memory (immediate and delayed recall) and visuospatial episodic memory (immediate and delayed recall and recognition). Functional capacity outcomes were significantly related to the cognitive test results. Seventy-five percent of patients had a Modified Rankin Scale score of 0 or 1. Conclusions. Our results indicate good functional outcomes in a selected group of BAOD survivors, despite the presence of subnormal performance on some cognitive tests, including tests of attention, executive function, and long-term memory.

Grey matter changes in cognitively impaired Parkinson's disease patients

Background

Cortical changes associated with cognitive decline in Parkinson's disease (PD) are not fully explored and require investigations with established diagnostic classification criteria.

Objective

We used MRI source-based morphometry to evaluate specific differences in grey matter volume patterns across 4 groups of subjects: healthy controls (HC), PD with normal cognition (PD-NC), PD with mild cognitive impairment (MCI-PD) and PD with dementia (PDD).

Methods

We examined 151 consecutive subjects: 25 HC, 75 PD-NC, 29 MCI-PD, and 22 PDD at an Italian and Czech movement disorder centre. Operational diagnostic criteria were applied to classify MCI-PD and PDD. All structural MRI images were processed together in the Czech centre. The spatial independent component analysis was used to assess group differences of local grey matter volume.

Results

We identified two independent patterns of grey matter volume deviations: a) Reductions in the hippocampus and temporal lobes; b) Decreases in fronto-parietal regions and increases in the midbrain/cerebellum. Both patterns differentiated PDD from all other groups and correlated with visuospatial deficits and letter verbal fluency, respectively. Only the second pattern additionally differentiated PD-NC from HC.

Conclusion

Grey matter changes in PDD involve areas associated with Alzheimer-like pathology while fronto-parietal abnormalities are possibly an early marker of PD cognitive decline. These findings are consistent with a non-linear cognitive progression in PD.

The effects of immunologic brainstem encephalopathy on cognitive function following awakening from a progressive autoimmune coma

We describe a unique patient who experienced a progressive autoimmune coma from age 14 to 17. The patient awoke after treatment with immunosuppressant medication. Although alertness, verbalization, and mobilization markedly improved, the patient reported persistent cognitive difficulties. Neuropsychological assessment from age 21 showed impairments in selective attention, distractibility, and memory. Conversely, higher-order executive functions were preserved. Electrophysiological analysis also identified abnormal neural signatures of selective attention. Eighteen months after the neuropsychological assessment, voxel-based morphometry revealed reduced white matter in the medulla compared to controls. The findings are discussed in terms of the impact of brainstem encephalopathy on cognitive mechanisms.

Structural alterations in brainstem of fibromyalgia syndrome patients correlate with sensitivity to mechanical pressure

Fibromyalgia syndrome is a chronic pain disorder characterised by widespread pain and tenderness in muscles and deep tissues. Current theories regarding the pathophysiological origins of fibromyalgia syndrome point towards central sensitisation and a decreased capacity of descending nociceptive controls. Morphological alterations to subcortical brain regions may contribute to such pathophysiological mechanisms, and to pain and other symptoms seen in fibromyalgia. Therefore, we evaluated geometric differences in subcortical structures in fibromyalgia patients relative to healthy people using a novel method of shape analysis. Sixteen female fibromyalgia patients and 15 age and sex matched, healthy control subjects underwent high-resolution T1-weighted magnetic resonance image scanning. Data was analysed using shape analysis of 15 subcortical regions and standard voxel-based morphometry analysis.

Fibromyalgia syndrome patients, relative to healthy control participants, exhibited alterations to the shape of the left lateral aspect of the lower brainstem (medulla). The mean total volume of the brainstem was also found to be significantly reduced in the patient group compared to healthy control subjects, and this brainstem volume reduction in patient group significantly correlated with clinical manual tender point scale scores. Voxel-based morphometry analysis revealed that patients also demonstrated decreased local grey matter volumes in the brainstem (pons) and left precuneus, and increased grey matter volumes in bilateral primary somatosensory cortices.

Results suggest that the volume reduction and associated geometric shape alterations seen in the brainstem of the patient group may contribute to sensitivity to pressure pain in fibromyalgia syndrome. This finding may be due to structure-related deficiencies in regions subserving descending nociceptive control.

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Fibromyalgia syndrome patients exhibited shape alterations in the brainstem.

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The mean brainstem volume was also significantly reduced in FMS patients.

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This volume reduction correlated with clinical manual tender point scores.

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Structural alterations in the brainstem may contribute to clinical symptoms of FMS.

Clinico-radiologic characteristics of long-term survivors of diffuse intrinsic pontine glioma

Diffuse intrinsic pontine glioma (DIPG) is the deadliest central nervous system tumor in children. The survival of affected children has remained poor despite treatment with radiation therapy (RT) with or without chemotherapy. We reviewed the medical records of all surviving patients with DIPG treated at our institution between October 1, 1992 and May 31, 2011. Blinded central radiologic review of the magnetic resonance imaging at diagnosis of all surviving patients and 15 controls with DIPG was performed. All surviving patients underwent neurocognitive assessment during follow-up. Five (2.6 %) of 191 patients treated during the study period were surviving at a median of 9.3 years from their diagnosis (range 5.3-13.2 years). Two patients were younger than 3 years, one lacked signs of pontine cranial nerve involvement, and three had longer duration of symptoms at diagnosis. One patient had a radiologically atypical tumor and one had a tumor originating in the medulla. All five patients received RT. Chemotherapy was variable among these patients. Neurocognitive assessments were obtained after a median interval of 7.1 years. Three of four patients who underwent a detailed evaluation showed cognitive function in the borderline or mental retardation range. Two patients experienced disease progression at 8.8 and 13 years after diagnosis. A minority of children with DIPG experienced long-term survival with currently available therapies. These patients remained at high risk for tumor progression even after long follow-ups. Four of our long-term survivors had clinical and radiologic characteristics at diagnosis associated with improved outcome.

The human frontal lobes and frontal network systems: an evolutionary, clinical, and treatment perspective

Frontal lobe syndromes, better termed as frontal network systems, are relatively unique in that they may manifest from almost any brain region, due to their widespread connectivity. The understandings of the manifold expressions seen clinically are helped by considering evolutionary origins, the contribution of the state-dependent ascending monoaminergic neurotransmitter systems, and cerebral connectivity. Hence, the so-called networktopathies may be a better term for the syndromes encountered clinically. An increasing array of metric tests are becoming available that complement that long standing history of qualitative bedside assessments pioneered by Alexander Luria, for example. An understanding of the vast panoply of frontal systems' syndromes has been pivotal in understanding and diagnosing the most common dementia syndrome under the age of 60, for example, frontotemporal lobe degeneration. New treatment options are also progressively becoming available, with recent evidence of dopaminergic augmentation, for example, being helpful in traumatic brain injury. The latter include not only psychopharmacological options but also device-based therapies including mirror visual feedback therapy.

Corpus callosum damage predicts disability progression and cognitive dysfunction in primary-progressive MS after five years

We aim to identify specific areas of white matter (WM) and grey matter (GM), which predict disability progression and cognitive dysfunction after five years in patients with primary-progressive multiple sclerosis (PPMS). Thirty-two patients with early PPMS were assessed at baseline and after five years on the Expanded Disability Status Scale (EDSS), and EDSS step-changes were calculated. At year five, a subgroup of 25 patients and 31 healthy controls underwent a neuropsychological assessment. Baseline imaging consisted of dual-echo (proton density and T2-weighted), T1-weighted volumetric, and diffusion tensor imaging. Fractional anisotropy (FA) maps were created, and fed into tract-based spatial statistics. To compensate for the potential bias introduced by WM lesions, the T1 volumes underwent a lesion-filling procedure before entering a voxel-based morphometry protocol. To investigate whether FA and GM volume predicted EDSS step-changes over five years and neuropsychological tests scores at five years, voxelwise linear regression analyses were performed. Lower FA in the splenium of the corpus callosum (CC) predicted a greater progression of disability over the follow-up. Lower FA along the entire CC predicted worse verbal memory, attention and speed of information processing, and executive function at five years. GM baseline volume did not predict any clinical variable. Our findings highlight the importance of damage to the interhemispheric callosal pathways in determining physical and cognitive disability in PPMS. Disruption of these pathways, which interconnect motor and cognitive networks between the two hemispheres, may result in a disconnection syndrome that contributes to long-term physical and cognitive disability.

Cognitive dysfunction in a patient with brainstem hemorrhage

A 54-year-old, right-handed male suffered sudden onset of vertigo and vomiting. He was diagnosed with brainstem hemorrhage, and treatment was administered. After the vertigo improved, he showed disturbance of attention and anterograde amnesia. Magnetic resonance imaging revealed a hematoma across the pons on both sides, but no lesions were obvious in the cerebellum or the cerebrum. Single photon emission tomography showed decreased perfusion not only in the brainstem but also in the bilateral frontal and temporal lobes. Amnesia and executive dysfunction decreased in the 8 months following the stroke onset, with improvement in regional cerebral blood flow to the frontal and temporal lobes. These findings suggest that a hemorrhage in the pons caused diaschisis resulting in a secondary reduction of activity in the cerebral cortex and the occurrence of cortical symptoms.

Comprehensive cognitive neurological assessment in stroke

BACKGROUND

Cognitive syndromes (CS) after stroke may be important to measure and monitor for management and emerging therapies.

AIM

To incorporate known behavioral neurological and neuropsychiatric syndromes into a bedside cognitive assessment in patients with stroke.

METHODS

A validated cognitive examination (comprehensive cognitive neurological test in stroke, Coconuts) was administered during the first month of stroke presentation and analyzed according to five large-scale networks for cognition and correlated with neuropsychological tests. Validity testing of the test was performed for overall sensitivity, specificity, positive predictive value and negative predictive value to stroke in comparison with MRI diagnosis of stroke as well as discriminant validity, construct validity and inter-rater reliability.

RESULTS

Overall the sensitivity of the Coconuts scale was 91% and specificity 35%, PPV 88% and NPV 41% vs stroke lesions using MRI. Cognitive syndrome frequencies: frontal network syndrome frequency was 908/1796 (51%), left hemisphere network syndrome frequency was 646/1796 (36%), right hemisphere network included 275/1796 (15.3%), occipitotemporal network for complex visual processing 107/1796 (6%), the hippocampal limbic network for amnesias and emotional disorders 397/1796 (22%) and miscellaneous network syndromes 481/1796 (27%).

CONCLUSION

The Coconuts is a valid and practical test of a comprehensive array of known behavioral neurological and neuropsychiatric syndromes in patients with stroke.

Cognitive, linguistic and affective disturbances following a right superior cerebellar artery infarction: a case study

The cerebellar cognitive affective syndrome (CCAS) is a neurobehavioral syndrome that may develop after congenital and acquired cerebellar lesions. The syndrome consists of deficits in executive functioning, spatial cognition, visual-spatial memory and language and also involves personality and behavioral changes. We describe a 58-year-old right-handed man who in addition to affective disturbances presented with a unique combination of cognitive and linguistic deficits following an ischemic infarction in the vascular territory of the right superior cerebellar artery (SCA). Neurocognitive and neurolinguistic examinations were performed in the acute phase (10 days post-onset) and lesion phase (four weeks post-onset) of the stroke. A Tc-99m-ECD SPECT study was performed five weeks after the stroke. Acute phase data revealed a generalized cognitive decline and mild transcortical sensory aphasia. In the lesion phase, the neurobehavioral tableau was dominated by executive dysfunctions, disrupted divided attention, disturbed visual-spatial organization and behavioral abnormalities. Neurolinguistic investigations disclosed visual dyslexia and surface dysgraphia. Reading of words and visual lexical decision tasks of words and nonwords were severely defective and predominantly characterized by visual errors. In addition, writing irregular and ambiguous words resulted in regularization errors (phonologically plausible errors based on phoneme-grapheme correspondence rules). In the absence of any structural damage in the supratentorial brain regions, a quantified SPECT study showed a relative hypoperfusion in the right cerebellar hemisphere and the left medial frontal lobe. CCAS is for the first time reported in association with visual dyslexia and surface dysgraphia. We hypothesize that the cognitive and linguistic deficits might result from functional disruption of the cerebellar-encephalic pathways, connecting the cerebellum to the frontal supratentorial areas which subserve attentional and planning processes. This phenomenon of crossed cerebellar-cerebral diaschisis is supported by SPECT findings revealing a hypoperfusion in the anatomoclinically suspected brain regions. The constellation of cognitive, linguistic and behavioral symptoms adds new evidence to the multifaceted area of cerebellar neurocognition and demonstrates that the cerebellum might play a crucial role in cognitive, linguistic, and affective processing.

The neuro-behavioural syndrome of brainstem disease

We describe two patients with isolated brainstem lesions who exhibited behavioural and cognitive changes that are commonly associated with frontal lobe pathology, as leading clinical features. These cases illustrate the role of distributed neural networks in cognitive and behavioural processes. The brainstem, frontal-subcortical and limbic systems are extensively and reciprocally linked via neurotransmitter projection pathways. We argue that cognitive and behavioural features in patients with brainstem lesions reflect remote effects of brainstem structures on frontal lobe and limbic regions, as a consequence of disruption to ascending neurotransmitter pathways.

A United Kingdom population-based study of intellectual capacities in children with and without soiling, daytime wetting, and bed-wetting

OBJECTIVE

The objective of this study was to examine differences in intellectual capacities between children with and without soiling, daytime wetting, and bed-wetting.

METHODS

This study was based on a population of >6000 children (age range: 7 years 6 months to 9 years 3 months; median: 7 years 6 months) from the United Kingdom-based Avon Longitudinal Study of Parents and Children. Data on wetting and soiling were obtained from a questionnaire completed by parents. The Wechsler Intelligence Scale for Children-Third Edition was administered at a research clinic.

RESULTS

Bed-wetting was associated with lower Wechsler Intelligence Scale for Children-Third Edition IQ scores compared with control subjects, particularly performance IQ. This difference remained after exclusion of children with an IQ of <70 and adjustment for gender, stressful life events, and sociodemographic background. There were fewer differences in IQ scores between children with and without soiling or daytime wetting. Co-occurring wetting and soiling were associated with lower IQ scores than isolated soiling, daytime wetting, or bed-wetting, but this was mostly attributable to an overrepresentation of children with an IQ of <70 in the co-occurrence group.

CONCLUSIONS

It is hypothesized that the differences in intellectual capacities between children with and without bed-wetting are associated with maturational deficits of the central nervous system. There was less evidence for differences in intellectual capacities between children with and without soiling and daytime wetting. The central nervous system is involved to a lesser extent in soiling and daytime wetting, because peripheral influences from the bladder and gut play a greater role.

Neurobehavioral alterations in an adolescent following posterior fossa tumor resection

The posterior fossa syndrome (PFS) consists of a variety of symptoms, including cerebellar mutism, behavioral disturbances and personality changes. We report longitudinal clinical, neuroradiological and neurobehavioral findings in a 19-year-old left-handed patient, diagnosed with attentional deficit hyperactivity disorder (ADHD) at the age of 12, who underwent posterior fossa tumor resection. Although the patient did not develop cerebellar mutism after surgery, marked apathy and emotional indifference, urinary retention, eye-lid apraxia and visual hallucinosis became apparent after a brief interval of normal functioning. Based on these findings it is argued that the PFS might be considered a semiological heterogeneous condition with variable clinical expressions. Long-term follow-up investigations revealed subtle, but significant cognitive and affective deficits, resembling the cerebellar cognitive affective syndrome in adults. As demonstrated by functional neuroimaging studies with SPECT, symptoms were associated with perfusional deficits in the anatomoclinically suspected supratentorial regions, reflecting the distant impact of the cerebellum on cognitive and affective functions.

Peduncular hallucinosis

Peduncular hallucinosis (PH) is a syndrome of hallucinations and brainstem symptoms which has only been described in single case reports. A detailed analysis of five patients was undertaken to investigate the clincial characteristics, hallucinations and behavioural abnormalities of PH in greater detail. Frequent clinical symptoms were oculomotor disturbances, impaired arousal, dysarthria and ataxia. In the chronic stage, sleep-wake cycle disturbances were common. Hallucinations were naturalistic, complex, scenic, mostly visual, but also combined visual-acoustic or visual-tactile and recurred stereotypically over months. Patients experienced their hallucinations as genuine and were unable to discriminate their percepts from reality. Neuropsychological testing disclosed severe impairments of episodic memory, occasionally coupled with confabulatory behaviour. By contrast, memory for hallucinations remained intact. Deficits of attentional and executive functions were found in a subgroup of patients. Associated abnormal behaviours were common, comprising confusion, delusional misidentification for persons and places, and loss of disease awareness. PH appeared after focal lesions in various regions, such as the midbrain, thalamus and pons. These findings document that subcortical, brainstem-related hallucinations are vivid, recurring percepts that have a strong naturalistic character and are often associated with cognitive and behavioural abnormalities. It seems likely that brainstem hallucinosis is caused by damage to ascending reticular systems and thalamocortical circuits. Available observations suggest that PH compromises cognitive functions which enable us to differentiate between illusionary percepts and reality, a reality monitoring system.

Metacognition in stroke: bedside assessment and relation to location, size, and stroke severity

BACKGROUND

Frontal syndromes are poorly represented on stroke scales, yet may constitute an important component of the neurologic deficit impacting treatment and rehabilitation efforts.

AIMS

To validate an assessment of a frontal network syndrome score (FNSS) in stroke and to ascertain the relationship of the FNSS to lesion location, volume, and severity in young people with stroke.

METHODS

Accrual through a cognitive stroke registry of young, alert, nonaphasic, nonencephalopathic, nonsubstance abuse prone people who were tested with the 16 domain FNSS within 4 weeks of their stroke. Lesion location was determined by the Cerefy 3-dimensional, digital, coxial brain atlas identifying 6 regions of cerebral interest. Lesion severity was assessed by the National Institute of Health Stroke Score and infarct volume was measured in cubic centimeters.

RESULTS

From a sample of 456 cases in the registry after exclusions of encephalopathy, depression, and aphasia, cases with frontal network syndrome encompassed 132 of 341 persons (39%). Of these patients (n=80) with mean age 45.7 years [confidence interval (CI): 43.4, 48.1], educational level 13.1 years (CI:12.5, 13.6), mean National Institute of Health Stroke Score of 3.3 (CI: 2.6, 4.0), and mean lesion volume 30.3 mL (CI: 13.7, 46.9), had full testing with the FNSS battery yielding sensitivity (93%), specificity (74%), positive predictive value (79%), negative predictive value (90%), and a good interrater reliability (kappa=0.89, P=0.001). Construct validity testing with 15 frontal neuropsychologic tests revealed good to excellent significant Pearson r values in 14 of 15 of the tests. There was no correlation (Pearson's) for lesion volume (r=0.07, P=0.52) but significant correlation with stroke severity (r=0.23, P=0.03). Analysis of variance testing of the FNSS revealed significant differences for all 6 domains without intergroup significant differences for frontal network syndrome domains in the stroke group.

CONCLUSIONS

The FNSS is a valid, practical measure of frontal syndromes in stroke. Frontal syndromes are common in young people with stroke and may be present no matter where the lesion, are not dependent on size of stroke and have a low correlation with stroke severity.

Chronic disorders of consciousness

The vegetative state and the minimally conscious state are disorders of consciousness that can be acute and reversible or chronic and irreversible. Diffuse lesions of the thalami, cortical neurons, or the white-matter tracts that connect them cause the vegetative state, which is wakefulness without awareness. Functional imaging with PET and functional MRI shows activation of primary cortical areas with stimulation, but not of secondary areas or distributed neural networks that would indicate awareness. Vegetative state has a poor prognosis for recovery of awareness when present for more than a year in traumatic cases and for 3 months in non-traumatic cases. Patients in minimally conscious state are poorly responsive to stimuli, but show intermittent awareness behaviours. Indeed, findings of preliminary functional imaging studies suggest that some patients could have substantially intact awareness. The outcomes of minimally conscious state are variable. Stimulation treatments have been disappointing in vegetative state but occasionally improve minimally conscious state. Treatment decisions for patients in vegetative state or minimally conscious state should follow established ethical and legal principles and accepted practice guidelines of professional medical specialty societies.

Motor aprosodia due to isolated brainstem stroke in a young woman

A 21 year old woman presented with coma and quadriparesis secondary to bilateral pontine infarction. Three weeks later motor aprosodia was the most notable neurological finding apart from mild asymmetric limb weakness. No other supratentorial lesion was noted on initial and subsequent multimodality magnetic resonance imaging and magnetic resonance perfusion imaging revealed right frontotemporal hypoperfusion. This is the first report of aprosodia with an isolated brainstem lesion.

Cognitive impairment in isolated subtentorial stroke

BACKGROUND

Recent case reports have implicated subtentorial lesions of the brainstem or cerebellum as part of the neurocognitive circuitry.

AIM

To determine whether cognitive impairment is part of the neurological deficit in isolated brainstem (IBSS) or cerebellar stroke (ICS), using bedside screening and formal neurocognitive assessment of higher cortical function.

METHODS

Accrual occurred through a hospital based stroke registry. Cognitive bedside tests and neuropsychological tests were employed for the detection of higher cortical function. Scores from each test were converted to age and education based z-scores. Scores at or below -1.5 SD were clinically defined 'impaired'. Scores were averaged across tests in each functional area.

RESULTS

Of the stroke patients (n = 1360), the infarct was isolated within the brainstem (IBSS) in (45 of 120 or 38%) and isolated within the cerebellum (ICI) in (37 of 79 or 46.8%). Comparison of the IBSS patients with cognitive impairment in one or more domains to those with brainstem (24 of 45 or 53%) and hemispheric cerebral infarcts: (43 of 72 or 58%) (Pearson Chi Square) was not significantly different (P = 0.49). The admission Canadian Neurological Score (mean 10.2, 95% CI: 9.7-10.2) and Rankin score at 1 month (mean 1.7, 95% CI: 2.1-1.4). Comparison of the number of ICI patients with cognitive impairment in one or more domains (13 of 37 or 35.1%) to those with cerebellar and hemispheric cerebral infarcts who had abnormal cognitive testing in one or more domains (16 of 36 or 44.4%) (Pearson Chi Square) was not significantly different (P = 0.41). The mean admission Canadian Neurological Scores for the ICI cases was 10.9 (95% CI: 10.5-11.2) on average. Their mean admission Rankin score was 1.7 (95% CI: 1.4-2.1). Neuropsychological testing for frontal/executive skills, immediate and delayed memory, and visuospatial abilities (n = 15), revealed that frontal abilities were most impacted by the isolated strokes in these patients (average frontal impairment index = -1.29 +/- 0.79) followed by delayed recall of verbal and visual information (mean = -1.18 +/- 1.17). Immediate memory (-0.51 +/- 0.75) and visuoconstructive skills (-0.06 +/- 0.88) were relatively spared. Overall, 47% of the patients showed impairment on frontal tasks while 40% had significant impairment in delayed recall. In contrast, only 13% had scores below the cutoff for immediate memory and none fell below the cutoff for visuoconstructive skills.

CONCLUSION

Cognitive impairment is a common sequel of isolated subtentorial stroke. The frequency of impairment is similar either because of isolated brainstem or isolated cerebellar infarct, and similar to cognitive impairment with cerebral hemispheric lesions. Frontal networks or metacognition is the most frequently involved domain.