Die Gangstörung bei Patienten mit orthostatischem Tremor

Der primäre orthostatische Tremor ist eine seltene Erkrankung, die einen hochfrequenten Tremor von 13-18 Hz der unteren Extremität beim Stehen aufweist mit einer Symptomlinderung beim Sitzen, Gehen oder Hinlegen. Der Erkrankung liegt ein pathologisches, ponto-zerebello-thalamo-kortikales Tremornetzwerk zugrunde, das auch im Liegen weiter aktiviert bleibt. Im Zusammenhang mit dieser Erkrankung befasst sich diese Dissertation mit folgenden Fragestellungen: 1) Wie verändert sich der Tremor bei der Transition vom Stehen zum Gehen? 2) Gibt es eine objektivierbare Gangstörung trotz subjektiver Symptomregredienz beim Gehen? 3) Kann der Tremor durch propriozeptive Reize moduliert und gegebenenfalls gelindert werden? In einer klinischen Untersuchung mittels eines drucksensitiven Laufbands und Oberflächen-Elektromyographie konnte gezeigt werden, dass der Tremor während des Gehens persistiert mit einer zwischenzeitlichen Verlagerung der Tremorfrequenz in höhere Frequenzbereiche. Die Tremorintensität zeigte sich zudem abhängig vom Gangzyklus und der muskulären Belastung während des Gehens. Diese Beobachtungen legen nahe, dass es zu einer Interaktion zwischen dem orthostatischen Tremor und oszillatorischen, supraspinalen Lokomotionsarealen kommt und dass die periphere Manifestation des Tremors durch spinale Interneuron-Verschaltungen moduliert wird. Mittels einer multimodalen, klinisch-apparativen Ganguntersuchung wurden spatiotemporale Gangparameter bei Patienten mit orthostatischem Tremor erhoben, die mit einer altersgleichen, gesunden Kohorte verglichen wurde. Patienten mit orthostatischem Tremor zeigten ein breitbasiges Gangmuster mit erhöhter Gangvariabilität. Das Gangmuster verschlechterte sich beim langsamen Gehen und unter Augenschluss passend zu einer ataktischen Gangstörung mit sensorischen- und/oder zerebellären Defiziten. Eine weitere Aggravation in der kognitiven Dual Task-Bedingung offenbarte zudem motorisch-kognitive Defizite der Patienten. Somit scheint beim orthostatischen Tremor eine komplexe Netzwerkerkrankung mit einer spezifischen spino-zerebello-frontokortikalen Gangstörung vorzuliegen. Schließlich wurde in Folge einer kontinuierlichen Muskelsehnenvibrationsstimulation der unteren Extremitäten bei Patienten mit orthostatischem Tremor eine Reduktion der Tremorintensität und Körperschwankungen beobachtet. Bei bislang limitierten medikamentösen und invasiven Behandlungsmöglichkeiten bietet diese Beobachtung Hoffnung auf eine neue, nicht-invasive Therapieoption für Patienten mit orthostatischem Tremor.Primary orthostatic tremor is a rare disorder with high-frequency (13-18 Hz) leg muscle contractions during standing with relief of symptoms while sitting, walking, and lying. Recent studies found a specific ponto-cerebello-thalamo-cortical tremor network with persisting activity during lying. The aim of this dissertation was to answer following questions: 1) How does the tremor change in response to the transition from standing to walking? 2) Is orthostatic tremor associated with a specific gait disorder despite patients' sensation of symptom relief while walking? 3) Can the tremor be modulated through a non-invasive proprioceptive stimulation? In a first study, we examined the tremor of patients with orthostatic tremor during standing and walking conditions on a pressure-sensitive treadmill by means of surface electromyography of different leg muscles. We found that the tremor persisted during walking. Directly after gait initiation, the tremor frequency was shifted towards higher frequencies, but returned to the initial frequency after gait termination. While walking, the tremor was modulated in dependence of the gait cycle and individual exerted muscle forces. These observations point to a non-linear interference between the tremor and the oscillatory activity in supraspinal locomotor areas; furthermore, they indicate that the peripheral manifestation of the tremor is likely modulated by spinal interneuron connections. In a second study, we performed a multi-conditional, instrument-based gait assessment in patients with orthostatic tremor and age-matched healthy controls. Patients showed a broad-based walking pattern with increased gait variability with aggravation during slow walking modes and while walking with eyes closed. These gait alterations resemble an ataxic gait disorder indicative of sensory and/or cerebellar deficits. In addition, patients' walking performance deteriorated during a cognitive dual task paradigm pointing to a motor-cognitive dysfunction. Overall, the gait impairment in orthostatic tremor manifests in a specific spino-cerebello-frontocortical gait disorder. In a third study, we examined the effects of a proprioceptive leg muscle stimulation via muscle tendon vibration in patients with orthostatic tremor. We found that this stimulation yielded a reduction of tremor intensity and postural sway. In the light of currently limited pharmacological and invasive treatment options for orthostatic tremor, the observations of this study might pave the way for a new, non-invasive treatment option for patients

Key gait findings for diagnosing three syndromic categories of dynamic instability in patients with balance disorders

With the emergence of affordable, clinical-orientated gait analysis techniques, clinicians may benefit from a general understanding of quantitative gait analysis procedures and their clinical applications. This article provides an overview of the potential of a quantitative gait analysis for decision support in three clinically relevant scenarios of early stage gait disorders: scenario I: gait ataxia and unsteadiness; scenario II: hypokinesia and slow gait; scenario III: apparently normal gait with a specific fall tendency in complex mobility situations. In a first part, we justify the advantages of standardized data collection and analysis procedures including data normalization and dimensionality reduction techniques that facilitate clinical interpretability of instrument-based gait profiles. We then outline typical patterns of pathological gait and their modulation during different walking conditions (variation of speed, sensory perturbation, and dual tasking) and highlight key aspects that are particularly helpful to support and guide clinical decision-making

The gait disorder in primary orthostatic tremor

OBJECTIVE To uncover possible impairments of walking and dynamic postural stability in patients with primary orthostatic tremor (OT). METHODS Spatiotemporal gait characteristics were quantified in 18 patients with primary OT (mean age 70.5 ± 5.9 years, 10 females) and 18 age-matched healthy controls. One-third of patients reported disease-related fall events. Walking performance was assessed on a pressure-sensitive carpet under seven conditions: walking at preferred, slow, and maximal speed, with head reclination or eyes closed, and while performing a cognitive or motor dual-task paradigm. RESULTS Patients exhibited a significant gait impairment characterized by a broadened base of support (p = 0.018) with increased spatiotemporal gait variability (p = 0.010). Walking speed was moderately reduced (p = 0.026) with shortened stride length (p = 0.001) and increased periods of double support (p = 0.001). Gait dysfunction became more pronounced during slow walking (p < 0.001); this was not present during fast walking. Walking with eyes closed aggravated gait disability as did walking during cognitive dual task (p < 0.001). CONCLUSION OT is associated with a specific gait disorder with a staggering wide-based walking pattern indicative of a sensory and/or a cerebellar ataxic gait. The aggravation of gait instability during visual withdrawal and the normalization of walking with faster speeds further suggest a proprioceptive or vestibulo-cerebellar deficit as the primary source of gait disturbance in OT. In addition, the gait decline during cognitive dual task may imply cognitive processing deficits. In the end, OT is presumably a complex network disorder resulting in a specific spino-cerebello-frontocortical gait disorder that goes beyond mere tremor networks

Determinants of functioning and health-related quality of life after vestibular stroke

BackgroundStroke accounts for 5–10% of all presentations with acute vertigo and dizziness. The objective of the current study was to examine determinants of long-term functioning and health-related quality of life (HRQoL) in a patient cohort with vestibular stroke.MethodsThirty-six patients (mean age: 66.1 years, 39% female) with an MRI-proven vestibular stroke were followed prospectively (mean time: 30.2 months) in the context of the EMVERT (EMergency VERTigo) cohort study at the Ludwig-Maximilians Universität, Munich. The following scores were obtained once in the acute stage (1 year after stroke): European Quality of Life Scale-five dimensions-five levels questionnaire (EQ-5D-5L) and Visual Analog Scale (EQ-VAS) for HRQoL, Dizziness Handicap Inventory (DHI) for symptom severity, and modified Rankin Scale (mRS) for general functioning and disability. Anxiety state and trait were evaluated by STAI-S/STAI-T, and depression was evaluated by the Patient Health Questionnaire-9 (PHQ-9). Voxel-based lesion mapping was applied in normalized MRIs to analyze stroke volume and localization. Multiple linear regression models were calculated to determine predictors of functional outcome (DHI, EQ-VAS at follow-up).ResultsMean DHI scores improved significantly from 45.0 in the acute stage to 18.1 at follow-up (p ConclusionThe average functional outcome of strokes with the chief complaint of vertigo and dizziness is favorable. The most relevant predictors for individual outcomes are the personal anxiety trait (especially in combination with the female sex), the initial symptom intensity, and lesion volume. These factors should be considered for therapeutic decisions both in the acute stage of stroke and during subsequent rehabilitation.</p