Abnormal Gait

As the body moves forward, one limb typically provides support while the other limb is advanced in preparation for its role as the support limb. The gait cycle (GC) is composed of stance and swing phases. The stance phase is further subdivided into 3 segments including:

• Initial double stance
• Single limb stance
• Terminal double limb stance

Duration of each aspect of stance decreases as walking velocity increases. The transition from walking to running is marked by elimination of double support.
A stride is the equivalent of a gait cycle. The duration of a stride is the interval between sequential initial floor contacts by the same limb.

Walking posture changes only slightly with age:

• Unless the elderly have diseases such as osteoporosis with kyphosis, they walk upright with no forward lean.
• Elderly people also walk with about a 5° greater "toe out", possibly due to a loss of hip internal rotation or in a subconscious strategy to increase stability.
• Ground clearance as the foot swings is the same in elderly as in younger people.
• Gait velocity remains stable until about 70, then falls about 15% per decade for normal gait.
  • Velocity is lower because older people take shorter steps.
  • One explanation for this is that calf muscles are weaker and cannot produce sufficient plantar flexion.
  • Another is that the elderly are reluctant to generate plantar flexion power because of poor balance and poor control of the centre of mass whilst standing on one foot momentarily.
• Cadence (rhythm) does not change with age.
  • Everyone has a preferred cadence, which relates to leg length and usually represents the most energy-efficient rhythm for individual body structure.
  • Tall people take longer steps at a slower cadence.
  • Short people take shorter steps at a faster cadence.
• Double stance (the time when both feet are on the ground) increases with age – from 18% of a total gait cycle in young adults to approximately 26% in healthy elderly people.
  • During double stance, the centre of mass is between the feet, which is a stable position.
  • Increased time in the double stance position reduces momentum and therefore reduces time for the swing leg to advance and contributes to short step length.
  • Increased double stance may be needed on uneven ground or when balance is impaired, so that step length is compromised for stability. Elderly people with a fear of falling increase their double stance time.
• Joint motion changes with age.
  • Ankle plantar flexion is reduced during the late stage of stance, just before the back foot lifts off.
  • Maximal ankle dorsiflexion is not reduced.

The presence of neurological gait abnormalities in the elderly (without dementia) at base line assessment, is a significant predictor of the risk of development of dementia - especially non-Alzheimer's dementia.²

In this the patient avoids certain movements to avoid acute pain. It can be seen as a feature of:

• Trauma
• Osteoarthritis
• Pelvic girdle pain

Aetiology

This may include trauma, toxic and metabolic causes, neoplasms, immune mechanisms and genetic diseases.³ It may also arise from multiple sclerosis. It may also arise developmentally as congenital ataxia.
In children this is a non progressive disorder in which coordination will usually improve with age. Children aged between two and ten may also present with sub-acute reversible ataxia stemming from a viral infection.

Characteristics

• Broad-based gait
• Lurching quality
• Difficult to turn
• Difficulty walking in a straight line
• Broad-based posture

Assessment should include asking the patients to walk heel to toe.
The duration of the problem should be established and knowledge of previous and early motor abilities may be helpful.
Diurnal variation with morning unsteadiness which decreases later in the day may suggest raised intracranial pressure. It is also possible that patients may present with cerebellar ataxia of extremely acute onset and this may be accompanied by headache, vertigo, vomiting, altered consciousness and neck stiffness. In this case urgent referral for diagnosis is needed.

The bradykinesia and slowness of postural adjustments, together with a forward-flexed posture produces the "festinant gait" typical of Parkinson's disease.

After a cerebrovascular event:

• The strong gluteals and quadriceps muscle groups are generally spastic.
• The hip flexors, hamstrings and dorsiflexors of the foot are generally weak.
• The hip and knee will thus be stiff and slightly flexed.
• The foot will be plantar-flexed and tending to drag along the floor.

This indicates pyramidal pathway damage - and the residual power left is dependent on non-pyramidal pathways and there being enough residual cortical function.

Aetiology

These disorders can arise from:

• Diabetes
• Alcoholism
• HIV
• Toxin exposure
• Metabolic abnormalities
• Vitamin deficiency
• Adverse effects of certain drugs

However 32-70% of all peripheral neuropathies are idiopathic.⁴

Characteristics

Unsteady gait, often high stepping.
This is virtually diagnostic of neuropathies when present.
Patients may fall over if asked to close their eyes.

Damage to the descending corticospinal tract e.g. by a tumour may present initially with a generalised stiffening of the legs.
The patient may find it impossible to walk quickly or run because of a stiff-legged gait.
Ankle clonus may be a feature, and eventually develops into a spastic, foot dragging "shoe scuffing" gait.

Aetiology

Usually seen in spastic cerebral palsy, usually diplegic and paraplegic varieties

Characteristic features

• Legs flexed slightly at the hips and knees, giving the appearance of crouching, with the knees and thighs hitting or crossing in a scissors-like movement.
• Often mixed with or accompanied by spastic gait, a stiff, foot-dragging walk caused by one-sided, long-term muscle contraction.
• The individual is forced to walk on tiptoe unless the dorsiflexor muscles are released by an orthopaedic surgical procedure.
• Muscle contractures of the adductors result in thighs and knees rubbing together and crossing in a manner analogous to scissors.
• There may also be complicated assisting movements of the upper limbs when walking.

These features are typical and are usually present to some degree regardless of the mildness or severity of the cerebral palsy.

Patients with unilateral vestibular disorders:

• Will veer to the affected side (as opposed to a generalised instability with bilateral vestibular or cerebellar disorders).
• There is a wide-based gait and their difficulties are exaggerated by asking them to walk heel-to-toe.

Many patients respond well to a simple home program of vestibular rehabilitation head movement exercises. This results in reduced symptoms of imbalance during stance and gait.⁵

This is a videotape-based analysis of 16 facets of human gait.⁶ The scale comprises three categories:

• Five general categories
• Four lower limb categories
• Seven trunk, head and upper limb categories

Each item has a score range from 0 (good function) to 3 (poor function).
The total GARS score is the sum of the 16 individual items. The total score represents a rank ordering of risk for falling, based on the number of gait abnormalities recognised and the severity of any abnormality identified.