Chapter 024. Gait and Balance Disorders (Part 5) ppt

Chapter 024. Gait and Balance Disorders
(Part 5)

Falls
Falls are a common event, particularly among the elderly. Modest changes
in balance function have been described in fit older subjects as a result of normal
aging. Subtle deficits in sensory systems, attention, and motor reaction time
contribute to the risk, and environmental hazards abound.
Epidemiologic studies have identified a number of risk factors for falls,
summarized in Table 24-3. A fall is not a neurologic problem, nor reason for
referral to a specialist, but there are circumstances in which neurologic evaluation
is appropriate. In a classic study, 90% of fall events occurred among 10% of
individuals, a group known as recurrent fallers.
Some of these are frail older persons with chronic diseases. Recurrent falls
sometimes indicate the presence of serious balance impairment. Syncope, seizure,
or falls related to loss of consciousness require appropriate evaluation and
treatment (Chaps. 21 and 363).

Table 24-3 Risk Factors for Falls, a Meta-Analysis: Summary of
Sixteen Controlled Studies

Risk Factor Mean RR (OR)

Range
Weakness 4.9 1.9–10.3

Balance deficit 3.2 1.6–5.4
Gait disorder 3.0 1.7–4.8
Visual deficit 2.8 1.1–7.4
Mobility limitation 2.5 1.0–5.3
Cognitive impairment 2.4 2.0–4.7

Impaired functional status

2.0 1.0–3.1
Postural hypotension 1.9 1.0–3.4

Note: RR, relative risks from prospective studies; OR, odds ratios from
retrospective studies.
Source: Reprinted from Masdeu et al, with permission.The descriptive
classification of falls is as difficult as the classification of gait disorders, for many
of the same reasons. Postural control systems are widely distributed, and a number
of disease-related abnormalities occur. Unlike gait problems that are apparent on
observation, falls are rarely observed in the office. The patient and family may
have limited information about what triggered the fall. Injuries can complicate the
physical examination. While there is no standard nosology of falls, common
patterns can be identified.
Slipping, Tripping, and "Mechanical Falls"
Slipping on icy pavement, tripping on obstacles, and falls related to obvious
environmental factors are often termed mechanical falls. They occasionally occur
in healthy individuals with good balance compensation. Frequent tripping falls
raise suspicion about an underlying neurologic deficit. Patients with spasticity, leg
weakness, or foot drop experience tripping falls.
Weakness and Frailty
Patients who lack strength in antigravity muscles have difficulty rising from
a chair, fatigue easily when walking, and have difficulty maintaining their balance
after a perturbation. These patients are often unable to get up after a fall and may
be on the floor for an hour or more before help arrives. Deconditioning of this sort
is often treatable. Resistance strength training can increase muscle mass and leg
strength in people in their 80s and 90s.
Drop Attacks and Collapsing Falls
Drop attacks are sudden collapsing falls without loss of consciousness.

Patients who collapse from lack of postural tone present a diagnostic challenge.
The patient may report that his or her legs just gave out underneath; the family
may describe the patient as "collapsing in a heap." Orthostatic hypotension may be
a factor in some such falls. Asterixis or epilepsy may impair postural support. A
colloid cyst of the third ventricle can present with intermittent obstruction of the
foramen of Monroe, resulting in a drop attack. While collapsing falls are more
common in older patients with vascular risk factors, they should not be confused
with vertebrobasilar ischemic attacks.