Dennis A. Nowak

Consensus Paper: Revisiting the Symptoms and Signs of Cerebellar Syndrome

The cerebellum is involved in sensorimotor operations, cognitive tasks and affective processes. Here, we revisit the concept of the cerebellar syndrome in the light of recent advances in our understanding of cerebellar operations. The key symptoms and signs of cerebellar dysfunction, often grouped under the generic term of ataxia, are discussed. Vertigo, dizziness, and imbalance are associated with lesions of the vestibulo-cerebellar, vestibulo-spinal, or cerebellar ocular motor systems. The cerebellum plays a major role in the online to long-term control of eye movements (control of calibration, reduction of eye instability, maintenance of ocular alignment). Ocular instability, nystagmus, saccadic intrusions, impaired smooth pursuit, impaired vestibulo-ocular reflex (VOR), and ocular misalignment are at the core of oculomotor cerebellar deficits. As a motor speech disorder, ataxic dysarthria is highly suggestive of cerebellar pathology. Regarding motor control of limbs, hypotonia, a- or dysdiadochokinesia, dysmetria, grasping deficits and various tremor phenomenologies are observed in cerebellar disorders to varying degrees. There is clear evidence that the cerebellum participates in force perception and proprioceptive sense during active movements. Gait is staggering with a wide base, and tandem gait is very often impaired in cerebellar disorders. In terms of cognitive and affective operations, impairments are found in executive functions, visual-spatial processing, linguistic function, and affective regulation (Schmahmann’s syndrome). Nonmotor linguistic deficits including disruption of articulatory and graphomotor planning, language dynamics, verbal fluency, phonological, and semantic word retrieval, expressive and receptive syntax, and various aspects of reading and writing may be impaired after cerebellar damage. The cerebellum is organized into (a) a primary sensorimotor region in the anterior lobe and adjacent part of lobule VI, (b) a second sensorimotor region in lobule VIII, and (c) cognitive and limbic regions located in the posterior lobe (lobule VI, lobule VIIA which includes crus I and crus II, and lobule VIIB). The limbic cerebellum is mainly represented in the posterior vermis. The cortico-ponto-cerebellar and cerebello-thalamo-cortical loops establish close functional connections between the cerebellum and the supratentorial motor, paralimbic and association cortices, and cerebellar symptoms are associated with a disruption of these loops.

Functional neuromuscular stimulation to improve severe hand dysfunction after stroke: Does inhibitory rTMS enhance therapeutic efficiency?

BACKGROUNDnNovel strategies to improve hand function after stroke are needed. Electromyography-triggered functional neuromuscular stimulation (EMG-FNMS) and repetitive transcranial magnetic stimulation (rTMS) are promising techniques to facilitate recovery of sensory-motor hand dysfunction after stroke.nnnOBJECTIVEnTo investigate if 1Hz rTMS over the contralesional primary motor cortex enhances the effectiveness of EMG-triggered FNMS of the hand and finger extensors to improve severe sensory-motor hand dysfunction after stroke.nnnMETHODSn24 subjects with a first stroke received 10 daily sessions of 20 min EMG-triggered FNMS of the hand and finger extensors of the affected forearm preceded by 15 min of either 1Hz rTMS (rTMS group, n = 12) or sham rTMS (control group, n = 12) over the contralesional primary motor cortex. Prior to and after each intervention motor function and spasticity were rated at both hands, and cortical excitability of the contralesional primary motor cortex was assessed.nnnRESULTSnMotor function and spasticity of the affected hand were significantly improved by either intervention, whereas behavioural measures of the unaffected hand did not change. There were no significant differences between both intervention groups. Improvement of motor function of the affected hand was positively correlated with cortical excitability of the contralesional primary motor cortex after EMG-triggered FNMS preceded by 1Hz rTMS.nnnCONCLUSIONSn1Hz rTMS does not enhance the general effectiveness of EMG-FNMS to the wrist and finger extensors of the affected forearm after stroke. Motor recovery of the severely affected hand after stroke appears to depend on excitability of the contralesional primary motor cortex.

Dysphagia--a common, transient symptom in critical illness polyneuropathy: a fiberoptic endoscopic evaluation of swallowing study*.

Objectives:Critical illness polyneuropathy is a common disorder in the neurological ICU. Dysphagia is well known to deteriorate outcome in the ICU. The prevalence of dysphagia in critical illness polyneuropathy is not known. The aim of this study was to evaluate the prevalence of dysphagia in critical illness polyneuropathy using fiberoptic endoscopic evaluation of swallowing. Design:Prospective, cohort study. Setting:Neurological rehabilitation ICU. Patients:Twenty-two patients with critical illness polyneuropathy. Interventions:Clinical swallowing examination and serial fiberoptic endoscopic evaluation of swallowing (days 3, 14, and 28 after admission). Measurements and Main Results:Swallowing of saliva, pureed consistencies, and liquids was tested using fiberoptic endoscopic evaluation of swallowing at three different time points. The penetration-aspiration scale by Rosenbek et al and the secretion severity rating scale by Murray et al were used for grading. Functional outcome after rehabilitation was assessed using the functional independence measure.: Pathologic swallowing was found in 20 of 22 patients (91%). Hypesthesia of laryngeal structures was found in 17 of 22 patients (77%) during the first fiberoptic endoscopic evaluation of swallowing. Over the 4-week follow-up period, laryngeal hypesthesia resolved in 75% of affected cases. Pureed consistencies were swallowed safely in 18 of 22 cases (82%), whereas liquids and saliva showed high aspiration rates (13 of 17 [78%] and 10 of 22 [45%], respectively). Swallowing function recovered completely in 21 of 22 (95%) within 4 weeks. Conclusions:Dysphagia is frequent among patients with critical illness polyneuropathy treated in the ICU. Old age, chronic obstructive pulmonary disease, the mode of mechanical ventilation, the prevalence of tracheal tubes, and behavioral “learned nonuse” may all be contributing factors for the development of dysphagia in critical illness polyneuropathy. Complete recovery occurs in a high percentage of affected individuals within 4 weeks.

Inhibition of the contralesional dorsal premotor cortex improves motor function of the affected hand following stroke

Numerous studies have shown that repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex (M1) may improve motor function of the affected hand after stroke. The effects of 1 Hz rTMS applied over the contralesional dorsal premotor cortex (PMd) on hand function and cortical neurophysiology in subacute stroke were examined.

Meningoencephaloradiculomyelitis after tick-borne encephalitis virus infection: a case series

Background:u2002 Tick‐borne encephalitis (TBE) is caused by a RNA‐virus and is in about 50% of cases characterized by a biphasic clinical course in adults. Different clinical syndromes have been described, including meningitis, meningoencephalitis, meningoencephalomyelitis and meningoencephaloradiculomyelitis. The latter seems to be the most disabling and severe form of TBE virus infection.

The influence of weaning duration on rehabilitative outcome in early neurological rehabilitation

BACKGROUNDnWe investigated if longer weaning is associated with inferior rehabilitative outcome in critical illness polyneuropathy (CIP) and cerebrovascular diseases (CVD).nnnMETHODSnWe analysed retrospectively weaning protocols and medical histories of 171 tracheotomized patients with CIP and CVD. We assessed weaning durations (WD), independence in activities of daily living, as assessed by the functional independence measure (FIM), mortality rates and discharge modalities in each cohort. Weaning was performed using synchronized intermittent mandatory ventilation (SIMV) with Autoflow® and assisted spontaneous ventilation (ASV).nnnRESULTSnWD was significantly longer in CIP compared to CVD (p < 0.001). Despite shorter in-patient treatment and longer WD, patients with CIP acquired significantly greater gains of improvement than CVD (p = 0.015). Independent living at home was possible in 43% of patients with CIP and in 26% of CVD. Mortality was equal in both groups (13% vs. 6%, p > 0.05). Chronic obstructive pulmonary disease (COPD) showed a trend towards longer weaning durations in both entities (p = 0.06). Higher age significantly correlated with longer WD (p = 0.038, r = 0.16). Longer rehabilitation duration (RD) positively correlated with higher Delta-FIM (DFIM) in both entities (p = 0.006, r = 0.21).nnnCONCLUSIONnLonger weaning and its partly negative influence on rehabilitative outcome can be compensated by longer in-patient rehabilitation in CIP and CVD.

Recovery and outcome of frontal alien hand syndrome after anterior cerebral artery stroke

Ischemic lesions within the territory of the anterior cerebral artery present with a variety of clinical signs and symptoms. Among these, frontal alien hand syndrome is rare and easily overlooked in the acute clinical setting, but significantly impacts on functional activities of daily life. Given its rareness, very little is known about its long-term outcome. To shade some more light onto this issue, clinical presentation, course of rehabilitation and outcome of two illustrative cases of frontal alien hand syndrome following anterior cerebral artery stroke are presented. Within seven and nine months from symptom onset, respectively, the clinical symptoms of frontal alien hand had resolved completely in both cases. We conclude that frontal alien hand syndrome has a favourable long-term outcome.

Outcome of Intensive Care Unit-Dependent, Tracheotomized Patients with Cerebrovascular Diseases.

BACKGROUNDnOutcome studies in intensive care unit -dependent, tracheotomized, and mechanical ventilated patients with cerebrovascular disease (CVD) are scarce.nnnMETHODSnIn a retrospective approach, we analyzed the outcome of 143 patients with ischemic stroke (IS), primary intracerebral hemorrhage (PICH), and subarachnoid hemorrhage (SAH). To measure the potential benefit of in-patient rehabilitation, we used the Functional Independence Measure (FIM). In addition, weaning and rehabilitation duration, duration of mechanical ventilation (MV) in the acute care hospital (preweaning), and mortality rates were assessed.nnnRESULTSnApproximately 50% of all patients were transferred home. These patients were fully independent or under nursing support. We found no differences regarding weaning and rehabilitation durations, or FIM scores in between each entity. Log-regression analyses showed that every day on MV generates a 3.2% reduction of the possibility to achieve a beneficial outcome (FIMxa0≥xa050 points [only moderate assistance necessary]), whereas every day in-patient rehabilitation without MV increases the chance for favorable outcome by 1.9%. Mortality rates were 5% for IS and 10% for PICH and SAH, respectively.nnnCONCLUSIONSnThis study shows that even severely affected, tracheotomized patients with CVD benefit from early in-patient rehabilitation, irrespective of the etiology of vascular brain injury. Mortality rates of early rehabilitation in CVD are low. Until no validated outcome predictors are available, all efforts should be undertaken to enable in-patient rehabilitation, even in severe cases of CVD to improve outcome and to prevent accommodation in long-time-care facilities.

Parkinsonism following bilateral hypoxic-ischemic lesions of the striatum.

A 40-year-old white male received cardio-pulmonary resuscitation after cardiac arrest due to an epileptic status. Fourxa0months after the incident he developed an akinetic-rigid syndrome and a postural tremor more pronounced on the right side of the body. Brain imaging revealed bilateral lesions of the putamen and caudate nucleus. Levodopa improved bradykinesia and muscular rigidity, but not the postural tremor.

Electrify your brain: can a controversial technique enhance recovery of function after brain damage?

The number, connectivity and effectiveness of synapses in the adult human brain can be modified by learning across the entire lifespan. We all recall numerable examples of how members of the so called older generation develop amazing creativity to enhance their mental capacities by learning novel skills until very old age. The processes and mechanisms induced by learning on a cellular level are similar to those to be found during restoration of function after brain damage. Functional imaging of the brain has shown that there is widespread reorganization within various cortical areas of both the affected and unaffected hemispheres after brain damage, irrespective of the particular function that is lost. These changes in neural activity, although most commonly regarded to represent beneficial plasticity, may also represent maladaptive plasticity. Maladaptive plasticity in neural circuits may deteriorate the brain’s intrinsic potential for recovery of function and therefore may interfere with physical therapy. Non-invasive techniques of brain stimulation, such as transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), may be used to study beneficial and/or maladaptive plasticity of the cerebral cortex after brain lesion. Depending on the stimulation parameters applied tDCS can either inhibit or facilitate cortical excitability and these effects outlast the time of stimulation. The exact mechanisms underlying the changes of cortical excitability induced by tDCS are unknown, but are thought to reflect alterations in synaptic connectivity. Based on these lasting effects, brain stimulation may also be used to modify neural activity in an attempt to shift maladaptive plasticity towards beneficial plasticity. The therapeutic usefulness and efficiency of brain stimulation, however, is still a matter of ongoing debate. Several initial studies suggest that noninvasive brain stimulation may be a valuable adjunct in neurological rehabilitation. In this issue, Schabrun reviews the pertinent literature regarding the potential of tDCS to assist physical therapy in rehabilitation of motor performance of the affected hand after stroke or in Parkinson’s disease and to reduce pain scores in chronic pain syndromes. When the application follows the current safety guidelines tDCS appears to be a safe technique with only minor side effects. As highlighted in the review by Schabrun, only a handful of quite heterogeneous studies tested the effectiveness of tDCS in small samples of patients with stroke, Parkinson’s disease or chronic pain, among other disease entities. From these proof-of-principle studies we learn that several problems persist that need to be addressed prior to a more widespread application of the technique within phase II or III study designs. Future studies must be well-designed as well as feasible, which includes blinding of patients and assessors, and long-term follow-up. Among others the following questions must be addressed: (1) which stimulation parameters (time of stimulation, intensity) are most effective? (2) shall we stimulate over a longer period of time (several days or weeks or months)? (3) which hemisphere and brain area should be stimulated in a given clinical condition? (4) what is more effective: inhibition or facilitation of neural tissue? (5) at what time point or time period in the course of the disease is brain stimulation effective? (6) what are the long-term outcomes (and side effects) of brain stimulation? (7) should brain stimulation combined with conventional training therapies, such as physical therapy? If these questions remain unanswered, tDCS cannot be recommended for widespread adjunctive use in physical therapy practice.