Self-reported gait unsteadiness in mildly impaired neurological patients: an objective assessment through statistical gait analysis

Abstract

Background: Self-reported gait unsteadiness is often a problem in neurological patients without any clinical evidence of ataxia, because it leads to reduced activity and limitations in function. However, in the literature there are only a few papers that address this disorder. The aim of this study is to identify objectively subclinical abnormal gait strategies in these patients.

Methods: Eleven patients affected by self-reported unsteadiness during gait (4 TBI and 7 MS) and ten healthy subjects underwent gait analysis while walking back and forth on a 15-m long corridor. Time-distance parameters, ankle sagittal motion, and muscular activity during gait were acquired by a wearable gait analysis system (Step32, DemItalia, Italy) on a high number of successive strides in the same walk and statistically processed. Both self-selected gait speed and high speed were tested under relatively unconstrained conditions. Non-parametric statistical analysis (Mann-Whitney, Wilcoxon tests) was carried out on the means of the data of the two examined groups.

Results: The main findings, with data adjusted for velocity of progression, show that increased double support and reduced velocity of progression are the main parameters to discriminate patients with self-reported unsteadiness from healthy controls. Muscular intervals of activation showed a significant increase in the activity duration of the Rectus Femoris and Tibialis Anterior in patients with respect to the control group at high speed.

Conclusions: Patients with a subjective sensation of instability, not clinically documented, walk with altered strategies, especially at high gait speed. This is thought to depend on the mechanisms of postural control and coordination. The gait anomalies detected might explain the symptoms reported by the patients and allow for a more focused treatment design. The wearable gait analysis system used for long distance statistical walking assessment was able to detect subtle differences in functional performance monitoring, otherwise not detectable by common clinical examinations.

Figure 1

A subject instrumented with the STEP 32 system.

Figure 2

Maximum angle of ankle plantar-flexion and dorsi-flexion (degrees): mean value and standard deviation. Light grey bars correspond to patients, dark grey bars to controls. Self-selected speed (a) and high speed (b) values are reported.

Figure 3

Muscular activity means value and standard deviations. The value reported for each muscle corresponds to the percentage of stride in which the muscle is active. The muscles explored were Right and Left Erector Spinae (RES, LES), Gluteus Maximum (G MAX), Gluteus Medius (GME), Rectus Femoris (RF), Lateral Hamstrings (LH), Lateral Gastrocnemius (GAS) and Tibialis Anterior (TA). Light grey bars correspond to patients, dark grey bars to controls. Self-selected speed (a) and high speed (b) values are reported. A significant difference was found for RF ((p < 0.02) and TA (p < 0.008) when compared within the patients group at different speed.