Neurological gait assessment.

Gait disorders are a common feature of neurological disease. The gait examination is an essential part of the neurological clinical assessment, providing valuable clues to a myriad of causes. Understanding how to examine gait is not only essential for neurological diagnosis but also for treatment and prognosis. Here, we review aspects of the clinical history and examination of neurological gait to help guide gait disorder assessment. We focus particularly on how to differentiate between common gait abnormalities and highlight the characteristic features of the more prevalent neurological gait patterns such as ataxia, waddling, steppage, spastic gait, Parkinson's disease and functional gait disorders. We also offer diagnostic clues for some unusual gait presentations, such as dystonic, stiff-person and choreiform gait, along with red flags that help differentiate atypical parkinsonism from Parkinson's disease.

Acute truncal ataxia without nystagmus in patients with acute vertigo.

BACKGROUND AND PURPOSE: Differentiating between peripheral and central aetiologies can be challenging in patients with acute vertigo, given substantial symptom overlap. A detailed clinical history and focused physical eye movement examination such as the HINTS eye examination appear to be the most reliable approach to identify acute cerebellar/brainstem stroke, outperforming even acute brain imaging. We have observed, however, that isolated vertigo of central cause may be accompanied by acute truncal ataxia, in the absence of nystagmus. METHODS: We explored the frequency of ataxia without concurrent nystagmus in a cross section of patients with acute vertigo who presented to the emergency department at two centres in Argentina (Group A) and the UK (Group B). Patients underwent detailed clinical neuro-otological assessments (Groups A and B), which included instrumented head impulse testing and oculography (Group B). RESULTS: A total of 71 patients in Group A and 24 patients in Group B were included in this study. We found acute truncal ataxia-without nystagmus-in 15% (n = 14) of our overall cohort. Lesions involved stroke syndromes affecting the posterior inferior cerebellar artery, anterior inferior cerebellar artery, and superior cerebellar artery, thalamic stroke, cerebral hemisphere stroke, multiple sclerosis, and a cerebellar tumour. Additional oculomotor deficits did not reliably identify a central cause in these individuals, even with oculography. CONCLUSIONS: We have identified a significant subpopulation of patients with acute vertigo in whom the current standard approaches such as the HINTS examination that focus on oculomotor assessment may not be applicable, highlighting the need for a formal assessment of gait in this setting.

Priming overconfidence in belief systems reveals negative return on postural control mechanisms.

BACKGROUND: Modulation of postural control strategies and heightened perceptual ratings of instability when exposed to postural threats, illustrates the association between anxiety and postural control. RESEARCH QUESTION: Here we test whether modulating prior expectations can engender postural-related anxiety which, in turn, may impair postural control and dissociate the well-established relationship between sway and subjective instability. METHODS: We modulated expectations of the difficulty posed by an upcoming postural task via priming. In the visual priming condition, participants watched a video of an actor performing the task with either a stable or unstable performance, before themselves proceeding with the postural task. In the verbal priming paradigm, participants were given erroneous verbal information regarding the amplitude of the forthcoming platform movement, or no prior information. RESULTS: Following the visual priming, the normal relationship between trunk sway and subjective instability was preserved only in those individuals that viewed the stable but not the unstable actor. In the verbal priming experiment we observed an increase in subjective instability and anxiety during task performance in individuals who were erroneously primed that sled amplitude would increase, when in fact it did not. SIGNIFICANCE: Our findings show that people's subjective experiences of instability and anxiety during a balancing task are powerfully modulated by priming. The contextual provision of erroneous cognitive priors dissociates the normally 'hard wired' relationship between objective measures and subjective ratings of sway. Our findings have potential clinical significance for the development of enhanced cognitive retraining in patients with balance disorders, e.g. via modifying expectations.

Bedside video-ophthalmoscopy as an aid in the diagnosis of central vestibular syndromes.

The evaluation of central vestibular syndromes, especially in the acute setting, can pose a challenge even for the most experienced clinician. Of particular importance is the evaluation of ocular torsion and nystagmus, which can be sensitive for central vestibular pathology, but easily missed by the untrained eye. We present two cases of acute vestibular syndrome of central origin in which the use of magnified fundoscopy at the bedside aided the precise anatomical diagnosis to inform appropriate further management. We also review aspects of the pathophysiology and anatomy of vestibular roll plane disorders. In case 1, the finding of position-dependent ocular torsion facilitated a rapid distinction between central skew deviation and a trochlear nerve palsy. In case 2, the fundoscopic magnification identified a pure rotatory nystagmus indicative of a central vestibular disorder. Ophthalmoscopy remains a useful bedside technique in acute vertigo, but the use of inexpensive magnification with a smartphone can provide objective and recordable evidence of central vestibular pathology, aiding therapeutic decisions.

Subjective stability perception is related to postural anxiety in older subjects.

BACKGROUND: Under static conditions, the objective and subjective measures of postural stability correlate well. However, age-related changes in postural control and task-related anxiety may modify the relationship between these subjective and objective measures. Ultimately, patients' symptoms represent subjective reports, thus understanding this relationship has clinical implications. AIMS: This study investigates the relationship between subjective-objective measures of postural stability in dynamic conditions and whether this relationship is influenced by age or task-related anxiety. METHODS: 50 healthy participants (aged 18-83 years) stood on a platform oscillating at variable amplitudes, with-without a fall-preventing harness to modulate task-related anxiety. Trunk sway path, hip velocity and foot lifts (objective measures) and subjective scores of instability and task-related anxiety were recorded. RESULTS: The subjective perception of stability accurately matched objective body sway, following a logarithmic function profile (r2 = 0.72, p < 0.001). This function did not change significantly with age, harness or task presentation order. A strong relationship was observed between subjective measures of stability and task-related anxiety for all subjects (r = 0.81, p < 0.001). Task repetition reduced anxiety in the young, uncoupling anxiety changes from subjective instability, but not in the elderly who retained higher anxiety levels in line with subjective unsteadiness. DISCUSSION: Subjects accurately rate their own instability during dynamic postural challenges, irrespective of age and actual fall risk. However, anxiety may selectively modulate the perception of instability in older subjects. The perception of stability relies upon the integration of sensory afferents but also recruits emotional-cognitive processes, particularly in older individuals. The use of a safety harness has no influence on subjective or objective postural stability.