Gait disturbance in Alzheimer's disease: a clinical study.

Introduction

Gait disturbance is a characteristic feature of patients with vascular dementia [1]. In contrast, the NINCDS-ADRDA criteria for Alzheimer's disease (AD) state that: `gait disturbance at the onset or very early in the course of the illness' makes the diagnosis of probable AD uncertain or unlikely [2]. However, clinical studies suggest that gait disturbance is not restricted to the later stages of AD [3-6]. Also, studies in gait laboratories have identified abnormalities of gait and balance in patients with early AD [7-9].

Many of the gait disturbances found in elderly people and in those with dementia cannot be attributed to classical musculoskeletal, neuropathic, spastic, cerebellar or extrapyramidal syndromes [10]; these have been called higher-level gait disorders [11]. Terms used to describe these disorders include `gait apraxia', `senile gait', `lower-half parkinsonism' and `marche a petit pas'. Recently, Nutt et al. have attempted to bring some order to this terminological chaos by describing a clinical classification of higher-level gait disorders [11].

The clinical pattern of gait disturbance in patients with AD has attracted little attention to date. In this study, we used Nutt's classification to analyse higher-level gait disorders in patients with AD and controls.

Methods

Subjects: Patients with dementia and controls pair-matched for age ([+ or -]2 years), sex and location were recruited from the clinics and day-hospitals of a geriatric and a psychogeriatric unit. Patients referred specifically because of mobility problems or falls, and those who were bed- or chair-bound, had a history of stroke or Parkinson's disease, a Hachinski Ischaemic Score more than 4 [12], had been treated with neuroleptic medications within the previous year or had musculoskeletal, neuropathic or spastic causes of gait disturbance were excluded.

All patients with dementia satisfied the criteria for the clinical diagnosis of probable AD proposed by the NINCDS-ADRDA work group [2] (for the purpose of this study, gait disturbance was not considered when applying these criteria). Severity of dementia was defined using the Clinical Dementia Rating (CDR) scale, a global rating instrument comprising cognitive and behavioural domains: CDR 1 corresponds to mild, CDR 2 to moderate and CDR 3 to severe …