Relationship Between Olfactory Disturbance After Acute Ischemic Stroke and Latent Thalamic Hypoperfusion.

Odor detection, recognition, and identification were assessed in 19 acute ischemic stroke patients who had no magnetic resonance imaging-detectable thalamic lesions but in whom technetium-99m ethyl cysteinate dimer single photon emission tomography revealed thalamic hypoperfusion. Although these patients were unaware of reduced olfactory function, they exhibited significantly lower scores in tests for odor identification and recognition threshold as compared with 9 ischemic stroke controls that had normal thalamic hypoperfusion. However, absolute odor detection thresholds were similar in the 2 groups. These results demonstrate the usefulness of cerebral perfusion scintigraphy in assessing sensory loss after ischemic stroke and provide further evidence for the role of the thalamus in olfaction.

Continuous epileptiform discharges during sleep as an evolutionary pattern in patients with congenital Zika virus syndrome.

Congenital Zika virus syndrome (CZVS) is associated with severe neurological deficits. Clinical characteristics of epilepsy and the electroencephalographic (EEG) pattern in CZVS were documented in infancy. In this study, we aimed to describe the EEG findings observed during the follow-up of children with CZVS. Seventy-six EEGs of 55 children (60% female; mean age = 50 months) with confirmed CZVS were analyzed, considering the background, interictal, and ictal epileptiform discharges. Continuous (or almost continuous) epileptiform discharges during non-rapid eye movement sleep were identified in 22 (40%) patients. In 20 (90.1%) patients, the pattern was symmetrical, with an anterior predominance of the epileptiform activity. All patients with this pattern had epilepsy, which was severe in 15 (68.2%) and demanded polytherapy in 19 (86.4%). Subcortical calcifications (77.3%) and multifocal EEGs (72.8%) in earlier ages occurred more often in patients with this pattern. Other unspecific interictal EEG patterns were focal epileptiform discharges in 23 (41.8%) and multifocal activity in six (10.9%). In CZVS, continuous (or almost continuous) epileptiform discharges during sleep emerge as a pattern after the second year of life. This was associated with severe and drug-resistant epilepsy, but not necessarily with an apparent regression. Subcortical calcifications and multifocal epileptiform discharges in infancy are associated with this pattern.

Isolated truncal contrapulsion as a rare presentation of acute thalamic infarct.

Infarcts involving the thalamus can yield many deficits, including sensory syndromes, altered consciousness, and cognitive disturbances, depending on the thalamic vascular territory involved. Isolated truncal contrapulsion due to pure thalamic infarct has been rarely reported. Truncal lateropulsion is a compelling sensation of being pulled toward one side that cannot be explained by weakness or limb ataxia. It is commonly reported in lateral medullary infarcts. It may occur with lesions that involve the peripheral vestibular system, brainstem, cerebellum, basal ganglia, ponto-mesencephalic, and thalamic lesions. We hereby report a 64-year-old woman who presented with truncal contrapulsion as the sole manifestation of an acute right lateral thalamic infarct.

Thalamic Diaschisis in Acute Ischemic Stroke: Occurrence, Perfusion Characteristics, and Impact on Outcome.

BACKGROUND AND PURPOSE: Ipsilateral thalamic diaschisis (ITD) describes the reduction of thalamic function, metabolism, and perfusion resulting from a distant lesion of the ipsilateral hemisphere. Our aim was to evaluate the perfusion characteristics and clinical impact of ITD in acute middle cerebral artery stroke, which does not directly affect the thalamus. METHODS: One hundred twenty-four patients with middle cerebral artery infarction were selected from a prospectively acquired cohort of 1644 patients who underwent multiparametric computed tomography (CT), including CT perfusion for suspected stroke. Two blinded readers evaluated the occurrence of ITD, defined as ipsilateral thalamic hypoperfusion present on ≥2 CT perfusion maps. Perfusion alterations were defined according to the Alberta Stroke Program Early CT Score regions. Final infarction volume and subacute complications were assessed on follow-up imaging. Clinical outcome was quantified using the modified Rankin Scale. Multivariable linear and ordinal logistic regression analysis were applied to identify independent associations. RESULTS: ITD was present in 25/124 subjects (20.2%, ITD+). In ITD+ subjects, perfusion of the caudate nucleus, internal capsule, and lentiform nucleus was more frequently affected than in ITD- patients (each with P<0.001). In the ITD+ group, larger cerebral blood flow (P=0.002) and cerebral blood volume (P<0.001) deficit volumes, as well as smaller cerebral blood flow-cerebral blood volume mismatch (P=0.021) were observed. There was no independent association of ITD with final infarction volume or clinical outcome at discharge in treatment subgroups (each with P>0.05). ITD had no influence on the development of subacute stroke complications. CONCLUSIONS: ITD in the form of thalamic hypoperfusion is a frequent CT perfusion finding in the acute phase in middle cerebral artery stroke patients with marked involvement of subcortical areas. ITD does not result in thalamic infarction and had no independent impact on patient outcome. Notably, ITD was misclassified as part of the ischemic core by automated software, which might affect patient selection in CT perfusion-based trials.

Deep Brain Stimulation for the Treatment of Dejerine-Roussy Syndrome.

BACKGROUND/AIMS: Patients who suffer from Dejerine-Roussy syndrome commonly experience severe poststroke hemibody pain which has historically been attributed to thalamic lesions. Despite pharmacological treatment, a significant proportion of the population is resistant to traditional therapy. Deep brain stimulation is often appropriate for the treatment of resistant populations. In this review we aim to summarize the targets that are used to treat Dejerine-Roussy syndrome and provide insight into their clinical efficacy. METHODS: In reviewing the literature, we defined stimulation success as achievement of a minimum of 50% pain relief. RESULTS: Contemporary targets for deep brain stimulation are the ventral posterior medial/ventral posterior lateral thalamic nuclei, periaqueductal/periventricular gray matter, the ventral striatum/anterior limb of the internal capsule, left centromedian thalamic nuclei, the nucleus ventrocaudalis parvocellularis internis, and the posterior limb of the internal capsule. CONCLUSIONS: Due to technological advancements in deep brain stimulation, its therapeutic effects must be reevaluated. Despite a lack of controlled evidence, deep brain stimulation has been effectively used as a therapeutic in clinical pain management. Further clinical investigation is needed to definitively evaluate the therapeutic efficacy of deep brain stimulation in treating the drug-resistant patient population.

Computed Tomography Perfusion Abnormalities in Bilateral Thalamic Infarction Due to Artery of Percheron Occlusion.

OBJECTIVE: We aimed to report a novel case of hyperacute computed tomography (CT) perfusion imaging abnormalities in artery of Percheron infarction. METHODS: We described a case of a 74-year-old man who presented acutely to the emergency room with witnessed sudden onset altered level of consciousness. RESULTS: Although initial hyperacute CT brain imaging was reported as normal, subsequent magnetic resonance imaging revealed bilateral paramedian thalamic infarction. A retrospective review of CT perfusion imaging revealed perfusion mismatch in the bilateral thalami, which was not recognized in the hyperacute setting. CONCLUSION: Artery of Percheron occlusion is a well-described cause of bilateral paramedian thalamic infarction, but to date, we have not identified any reports of perfusion imaging abnormalities in the hyperacute setting. This case emphasizes the important role of perfusion imaging when clinical presentation is not typical for ischemic stroke, but is suspected, given an acute onset; its recognition may have led to the consideration of thrombolysis acutely in this case (stroke chameleon).

The Posterior Limb of the Internal Capsule as the Subcortical Transitional Zone of the Anterior and Posterior Circulations: Insights from Human 7T MRI.

BACKGROUND: In patients with cerebral infarction, identifying the distribution of infarction and the relevant artery is essential for ascertaining the underlying vascular pathophysiological mechanisms and preventing subsequent stroke. However, visualization of the basal perforating arteries (BPAs) has had limited success, and simultaneous viewing of background anatomical structures has only rarely been attempted in living human brains. Our study aimed at identifying the BPAs with 7T MRI and evaluating their distribution in the subcortical structures, thereby showing the clinical significance of the technique. METHODS: Twenty healthy subjects and 1 patient with cerebral infarction involving the posterior limb of the internal capsule (ICpost) and thalamus underwent 3-dimensional fast spoiled gradient-echo sequence as time-of-flight magnetic resonance angiography (MRA) at 7T with a submillimeter resolution. The MRA was modified to detect inflow signals from BPAs, while preserving the background anatomical signals. BPA stems and branches in the subcortical structures and their origins were identified on images, using partial maximum intensity projection in 3 dimensions. RESULTS: A branch of the left posterior cerebral artery (PCA) in the patient ran through both the infarcted thalamus and ICpost and was clearly the relevant artery. In 40 intact hemispheres in healthy subjects, 571 stems and 1,421 branches of BPAs were detected in the subcortical structures. No significant differences in the numbers of stems and branches were observed between the intact hemispheres. The numbers deviated even less across subjects. The distribution analysis showed that the subcortical structures of the telencephalon, such as the caudate nucleus, anterior limb of the internal capsule, and lenticular nucleus, were predominantly supplied by BPAs from the anterior circulation. In contrast, the thalamus, belonging to the diencephalon, was mostly fed by BPAs from the posterior circulation. However, compared with other subcortical structures, the ICpost, which marks the anatomical boundary between the telencephalon and the diencephalon, was supplied by BPAs with significantly more diverse origins. These BPAs originated from the internal carotid artery (23.1%), middle cerebral artery (38.5%), PCA (17.3%), and the posterior communicating artery (21.1%). CONCLUSIONS: The modified MRI method allowed the detection of the relevant BPA within the infarcted area in the stroke survivor as well as the BPAs in the subcortical structures of living human brains. Based on in vivo BPA distribution analyses, the ICpost is the transitional zone of the anterior and posterior cerebral circulations.

Dynamic changes in sleep-related breathing abnormalities in bilateral paramedian mesencephalon and thalamus stroke: a follow-up case study.

BACKGROUND: Bilateral paramedian thalamic stroke is characterized by hypersomnia, vertical gaze palsy, amnestic alteration, and apathic state. Combined lesion of the paramedian thalamus and mesencephalon bilaterally is extremely rare. Little is known about the breathing disturbances of the particular region due to the lesion. The following describes the specific case of a woman, age 62, with bilateral paramedian thalamic and mesencephalic stroke. Initially, the patient's complaints exhibited altered vigilance and vertical gaze palsy. Notably, following the acute phase, fluctuating hypersomnia was detected. The MRI (brain) revealed an ischemic lesion in the medial part of the mesencephalon and paramedian thalamus, bilaterally. AIMS: The aim of the present study is to elucidate the involvement and characteristics of sleep-related breathing abnormalities in the clinical manifestation of the combined paramedian thalamic and mesencephalic stroke. METHODS: Polysomnographic recordings were accomplished seven times with 1-week interval between the consecutive recordings, toward investigating the early changes of sleep and sleep-related breathing abnormalities. RESULTS: Sleep structure examination featured a decrease in N3 and REM ratio and an increase in N1 and N2 ratio with minimal improvement during the recovery period. In contrast, significant changes were found in the breathing pattern: the initial central apnea dominance was followed by obstructive apneas with a gradual decrease of the total pathological respiratory events. CONCLUSION: In addition to the structural abnormality of the sleep regulating network, sleep-disordered breathing is another possible cause of hypersomnia in patients afflicted with the present localization of the lesion.

[Spinal cord stimulation for thalamic pain: Case report and review of the current literature]. / Hochzervikale Rückenmarkstimulation bei Thalamusschmerz : Fallbericht und Übersicht zur aktuellen Literatur.

BACKGROUND: Spinal cord stimulation (SCS) is an established procedure for treatment of chronic neuropathic pain of peripheral origin. The efficacy of SCS in case of central poststroke pain (CPSP), especially thalamic pain, has not been adequately proven. OBJECTIVES: The efficacy of SCS as an extracranial neurostimulation method for the management of central pain syndrome was investigated. MATERIALS AND METHODS: In this study, relevant pharmacological and nonpharmacological measures for central pain management were reviewed. A case of successful SCS for thalamic pain after ischemic insult is presented. Explanatory approaches of pathophysiological processes and a review of the current literature underline our results. RESULTS: In the case presented, SCS was found effective in the treatment of thalamic pain. CONCLUSION: The efficacy of SCS might be caused by segmental and supraspinal processes and collaboration of activating and inhibiting pathways. The integrity of the spinothalamic tract is mandatory. SCS is a treatment option for central pain syndrome, especially thalamic pain. Comparable studies confirm the potency of this technique. In contrast to other neuromodulation procedures spinal cord stimulation is less invasive, has a lower perioperative risk and is often less expensive. Further studies are needed to define its potential and role in the treatment of thalamic pain.

Repeated head trauma is associated with smaller thalamic volumes and slower processing speed: the Professional Fighters' Brain Health Study.

OBJECTIVES: Cumulative head trauma may alter brain structure and function. We explored the relationship between exposure variables, cognition and MRI brain structural measures in a cohort of professional combatants. METHODS: 224 fighters (131 mixed martial arts fighters and 93 boxers) participating in the Professional Fighters Brain Health Study, a longitudinal cohort study of licensed professional combatants, were recruited, as were 22 controls. Each participant underwent computerised cognitive testing and volumetric brain MRI. Fighting history including years of fighting and fights per year was obtained from self-report and published records. Statistical analyses of the baseline evaluations were applied cross-sectionally to determine the relationship between fight exposure variables and volumes of the hippocampus, amygdala, thalamus, caudate, putamen. Moreover, the relationship between exposure and brain volumes with cognitive function was assessed. RESULTS: Increasing exposure to repetitive head trauma measured by number of professional fights, years of fighting, or a Fight Exposure Score (FES) was associated with lower brain volumes, particularly the thalamus and caudate. In addition, speed of processing decreased with decreased thalamic volumes and with increasing fight exposure. Higher scores on a FES used to reflect exposure to repetitive head trauma were associated with greater likelihood of having cognitive impairment. CONCLUSIONS: Greater exposure to repetitive head trauma is associated with lower brain volumes and lower processing speed in active professional fighters.

Lucid dreams, an atypical sleep disturbance in anterior and mediodorsal thalamic strokes.

BACKGROUND: Cognitive, affective, and behavioural disturbances are commonly reported following thalamic strokes. Conversely, sleep disorders are rarely reported in this context. OBSERVATIONS: Herein, we report the cases of two young patients admitted for an ischemic stroke located in the territories of the left pre-mammillary and paramedian arteries. Together with aphasia, memory complaint, impaired attention and executive functions, they reported lucid dreams with catastrophic content or conflicting situations. CONCLUSION: Lucid dreams are an atypical presentation in thalamic strokes. These cases enlarge the clinical spectrum of sleep-wake disturbances potentially observed after an acute cerebrovascular event.

Numbness in the tip of the tongue and lower lip caused by thalamic hemorrhage.

Although patients with isolated oral syndrome or facial sensory loss following stroke of thalamic ventroposteromedial (VPM) nucleus have been reported, there have been no reports of numbness in the tip of the tongue and lower lip. Furthermore, symptoms in the tip of the tongue caused by stroke are typically characterized as gustatory sensory disturbances. A 62-year-old hypertensive man experienced an acute onset of severe numbness in the left tip of the tongue and ipsilateral lower lip. Neurological examination revealed no other abnormalities except for the aforementioned numbness. Head computed tomography showed a small hematoma in the medial part of the right thalamus, most likely within the VPM nucleus. The somatosensory impulse of the tongue is conveyed via the lingual nerve, and it reaches the contralateral medial VPM proper via the trigeminal spinal nucleus. Therefore, thalamic stroke mainly involving the medial VPM proper has the potential to elicit numbness in the tip of the tongue. A major portion of the VPM nucleus is vascularized by the inferolateral arteries. The inferolateral arteries vary greatly in the number and position of the arteries and their tributaries, and small-vessel disease in this territory can present with diverse symptoms because of this complexity. These findings indicate that central neurological involvement should not be overlooked in the case of sensory disturbance restricted to the tip of the tongue and lip.

Updating of visual space across horizontal saccades in cerebellar and thalamic lesion patients.

Efference copies of motor commands are used to update visual space across saccades, ultimately ensuring transsaccadic constancy of space. Thalamic lesions have been shown to impair efference copy-based saccadic updating in an oculomotor context, i.e., when two successive saccades are required. Moreover, the cerebellum has also been discussed as one possible source of saccade-related efference copy signals. The present study aimed to investigate the effects of thalamic and cerebellar lesions on saccadic updating in a perceptual context. To this end, seven patients with focal cerebellar lesions, seven patients with focal thalamic lesions and 11 healthy controls completed a perceptual localisation task in which the position of a target had to be updated across a single horizontal saccade, while saccade-related event-related potentials (ERPs) were recorded. Contrary to the expectations, localisation precision in both patient groups did not differ from the respective controls. A positive ERP component with centroparietal distribution occurring from about 300 to 500 ms after saccade onset in the updating condition was observed equally pronounced in controls and thalamic lesion patients. In cerebellar lesion patients, there was evidence of a reduction of this relative positivity in the updating condition, particularly for leftward saccades. This finding suggests that cerebellar damage altered the neural processes underlying saccadic updating in a perceptual context without causing overt behavioural deficits.

'Distorteidolias' - fantastic perceptive distortion. A new, pure dorsomedial thalamic syndrome.

The role of the thalamus in the pathogenesis of the visual and auditory hallucinations has been reported under the name of peduncular hallucinosis, usually with coexisting midbrain involvement. These hallucinations typically take the form of dreamy de novo productions (phanteidolias), less often that of transformations of perceptions into new items (such as seeing faces in clouds) called pareidolias. However, hallucinations taking the form of a complex distortion of perception is a different phenomenon, which to our knowledge has not been reported. We studied 2 patients with complex, 'fantastic', perceptive distortion involving the visual and auditory systems after thalamic stroke limited to the region of the dorsomedial nucleus, sparing the intralaminar nuclei and the midbrain (explaining the lack of disorders of consciousness and confusional state). Our patients reported the modification of usual stimuli (face, body, voices) into unreal, fantastically distorted perceptions (monstrous change of shapes or sounds without appearance of new items). While the exact mechanism leading to such perceptive distortions remains unknown, a release phenomenon due to damage to the dorsomedial thalamus (probably affecting cholinergic system) responsible for a disinhibition of cortical function involved in familiarity of perception seems likely. We suggest that these hallucinations should be called 'distorteidolias'.

Minimally invasive procedures reduced the damages to motor function in patients with thalamic hematoma: observed by motor evoked potential and diffusion tensor imaging.

BACKGROUND: The purpose of this study was to observe changes in motor function using diffusion tensor imaging (DTI) and motor-evoked potential (MEP) in patients with thalamic hematoma treated by minimally invasive procedures. METHODS: Forty-three patients with thalamic hematoma were randomized to either a minimally invasive group (MI group) or a medical treatment group (MT group). The patients in the MI group underwent whole-brain DTI and MEP measurements both before and 2 weeks after the thalamic hematoma was evacuated by minimally invasive procedures. The fractional anisotropy (FA) values of the corticospinal tract (CST) in the internal capsule and MEP ipsilateral to the hematoma side and the contralateral side were determined and then compared with the MT group. RESULTS: DTI showed that fibers in the internal capsule ipsilateral to the hematoma decreased either in number or were interrupted because of hematoma-induced damages, and in both groups, the CST FA values on admission were significantly lower (0.428 ± 0.032 and 0.415 ± 0.048 for the MI and MT groups, respectively) than the control values. Two weeks after the hematoma was evacuated, the number of fibers and the FA values of the CST in the internal capsule had both increased significantly relative to the values on admission. MEP was recorded simultaneously in all patients who were treated with minimally invasive procedures, and the latency of MEP decreased compared with the MT group. As FA values of the CST in internal capsule increased and MEP appeared with its latency decreased, the modified National Institutes of Health Stroke Scale score decreased after the surgery. CONCLUSIONS: Minimally invasive procedures for thalamic hematoma evacuation could effectively reduce the degree of injury to the function as observed by a combination of DTI and MEP measurements.

Improved dexterity after chronic electrical stimulation of the motor cortex for central pain: a special relevance for thalamic syndrome.

OBJECTIVES: To demonstrate that motor cortex stimulation (MCS) could improve motor function in patients with neuropathic pain. METHODS: In this prospective clinical study of 38 patients referred for MCS as treatment for their neuropathic pain, we collected any declaration of improvement in motor performance that could be attributed to MCS. RESULTS: Ten patients (26%) declared a benefit in their motor function. Eight presented objective evidence of recovered dexterity for rapid alternating movements. A minor proportion had improvement in dystonic posture (n = 2), but none had detectable increased motor strength or tonus changes. Overall, 73% of the patients with limb ataxia declared a benefit after MCS. In 6 out of 10 patients (60%), the anatomic lesion responsible for pain was restricted to the lateral aspect of the thalamus. All of them had either clinical or electrophysiological evidence of lemniscal dysfunction (proprioceptive ataxia). No correlation was found between the scores of pain relief and the modification of motor status. The correlation between thalamic lesions and benefits in motor performance was significant (Fisher's exact test, two-tailed, p = 0.0017). CONCLUSIONS: Up to 26% of patients estimated that MCS improved their motor outcome through recovered dexterity and in cases of lateral thalamic lesions.

Characteristics and sequelae of intracranial hypertension after intracerebral hemorrhage.

INTRODUCTION: The characteristics and sequelae of intracranial hypertension after ICH are unclear. METHODS: In a cohort of patients with spontaneous ICH, we obtained ICP values from nursing documentation of hourly vital signs and reviewed charts to rule out spurious ICP recordings. We used multiple logistic regression to explore factors associated with intracranial hypertension, and ordinal logistic regression controlling for the ICH score to examine the relationship between intracranial hypertension and the mRS score at 12 months. RESULTS: Among 243 patients, 57 (24 %) underwent ICP monitoring, of whom 40 (70 %; 95 % CI 57-82 %) had an episode of ICP > 20 mmHg. Intracranial hypertension was less likely in older patients (OR per decade 0.6, 95 % CI 0.3-0.9) and after infratentorial hemorrhage (OR 0.1, 95 % CI 0-0.7). Intracranial hypertension was not independently associated with mRS scores (OR 0.8, 95 % CI 0.3-2.3); this remained true for a threshold of >25 mmHg (OR 0.5, 95 % CI 0.2-1.5), number of elevations (OR 0.98 per elevation, 95 % CI 0.96-1.00), or area under the curve (OR 1.00 per mmHg × h, 95 % CI 0.99-1.01). Among patients with intracranial hypertension, seven (18 %) were functionally independent (mRS 0-2) at 12 months. Our results were not significantly changed after excluding patients with early DNR orders. CONCLUSION: Intracranial hypertension is common after ICH, especially in younger patients with supratentorial hemorrhage. Given active treatment of elevated ICP, intracranial hypertension does not appear associated with long-term outcomes, suggesting that ICP elevations should not necessarily be taken to signify a poor prognosis.