Ataxic Gait in Essential Tremor: A Disease-Associated Feature?

Abstract

BackgroundWhile accumulating evidence suggests that balance and gait impairments are commonly seen in patients with essential tremor (ET), questions remain regarding their prevalence, their relationship with normal aging, whether they are similar to the impairments seen in spinocerebellar ataxias, their functional consequences, and whether some ET patients carry greater susceptibility.MethodsWe conducted a literature search (until December 2018) on this topic.ResultsWe identified 23 articles on gait or balance impairments in ET. The prevalence of balance impairment (missteps on tandem walk test) was seven times higher in ET patients than controls. Gait impairments in ET included reduced speed, increased asymmetry, and impaired dynamic balance. While balance and gait problems worsened with age, ET patients were more impaired than controls, independent of age. The pattern of impairments seen in ET was qualitatively similar to that seen in spinocerebellar ataxias. Balance and gait impairments resulted in greater number of near falls in ET patients. Factors associated with balance and gait impairments in ET included age, presence of tremor in midline structures, and cognitive dysfunction.DiscussionAccumulating evidence suggests that balance and gait impairments are common in ET patients and occur to a greater extent in controls. Thus, they represent a disease-associated feature. These impairments, which are qualitatively similar to those seen in spinocerebellar ataxias, are not merely subclinical but result in difficulty performing functional tasks and increase falls risk. A subset of patients is more susceptible to balance and gait impairments. The full spectrum of impairments remains to be characterized.

Essential tremor: the most common form of cerebellar degeneration?

“…In a study of a 104 ET patients and 40 controls [ 72 ], in which patients were studied using quantitative gait analysis, ET gait was characterized under standard walking conditions by slower gait speed, problems with dynamic balance and gait temporal asymmetry. This constellation of impairments is similar to that which is seen in patients with cerebellar ataxic gait [ 27 , 73 – 75 ]. Although the gait abnormality in ET is milder than that seen in patients with most forms of SCA, it does have clinical and functional consequences, with studies indicating that ET patients may exhibit reduced functional mobility both in terms of self-reported measures of gait confidence and in performance-based measures [ 27 , 68 , 69 ] and increased numbers of self-reported falls [ 69 ].…”

“…The degenerative cerebellar ataxias comprise a heterogeneous group of disorders whose hallmark clinical feature is ataxia, and this is accompanied, to variable degrees, by additional clinical features that are referable to cerebellar dysfunction [1][2][3][4][5][6]. ET is an exceptionally common neurological disease [22] whose primary motor feature is action tremor [23], although patients often manifest intention tremor [24][25][26], mild gait ataxia [27] and other features of cerebellar dysfunction [28]. In this paper, we review the abundant evidence derived from clinical, neuroimaging and postmortem studies, linking ET to cerebellar dysfunction.…”

“…Apart from tremor, a number of other motor features have been described in ET patients and these features point towards an underlying abnormality of the cerebellum or its projections. The most clinically-evident of these clinical features is gait ataxia, which is generally mild [27,[63][64][65][66][67][68][69][70]. In some ET patients, however, gait ataxia can be of moderate severity [71].…”

“…Essential tremor (ET) is a common neurological disease [ 22 ]. Its primary motor feature is action tremor [ 23 ], although patients often manifest intention tremor [ 24 – 26 ], mild gait ataxia [ 27 ] and other features of subtle cerebellar dysfunction [ 28 ]. The pathophysiology is of ET unclear, and is likely heterogeneous.…”

Prospective Longitudinal Study of Gait and Balance in a Cohort of Elderly Essential Tremor Patients

“…However, it is now understood that ET patients can have other motor and non-motor symptoms and signs (3)(4)(5). Impairments in gait and balance have been documented across numerous studies (6)(7)(8), as have problems with cognition (9, 10), sleep (11,12), and mood (4,13). Gait and balance impairments in ET are often mild, but in some patients they can be severe; furthermore, in some cases they are associated with functional sequelae in terms of increased risk of falls and reduced balance confidence (8,(14)(15)(16).…”