Second edition

01.qxd 3/10/08 9:33 AM Page 14
14 Diagnostic assessment
Drift
A positive pronator drift test may be the first evidence of
hemiparesis. This test, according to DeJong (1979), is
accomplished by asking patients (with their eyes closed) to
fully extend their upper extremities, palms up, and then
maintain that position: a positive test consists of ‘slow
pronation of the wrist, slight flexion of the elbow and fingers,
and a downward and lateral drift of the hand’.
Rigidity
Rigidity should, at a minimum, be assessed at the elbows,
wrists, and knees by passive flexion and extension at the
joint, with close attention to the appearance of spastic, lead
pipe, or cogwheel rigidity. Spastic rigidity, seen with upper
motor neuron lesions, is most noticeable on attempted
extension of the upper extremity at the elbow and
attempted flexion of the lower extremity at the knee.
Furthermore, in spasticity, one may see the ‘clasp knife’
phenomenon. Here, on attempted rapid extension of the
upper extremity at the elbow, an initial period of minimal
resistance is quickly followed by a ‘catch’ of increased
resistance, which, in turn, is eventually followed by a loosening,
with the whole experience reminiscent of what it
feels like to open the blade on clasp knife. Lead pipe rigidity,
seen in parkinsonism, is, in contrast with spastic rigidity,
characterized by a more or less constant degree of
rigidity throughout the entire range of motion, much as if
one were manipulating a thick piece of solder. Cogwheel
rigidity, also seen in parkinsonism, may accompany lead
pipe rigidity or occur independently. This is best appreciated
by gently holding the patient’s elbow in the cup of
your hand while pressing down on the patient’s biceps tendon
with your thumb. Once the arm is thus supported,
with your other hand gradually extend the arm. When cogwheeling
is present, a ‘ratcheting’ motion will be appreciated
with your thumb, much as if there were a ‘cogwheel’
inside the joint.
After testing for these forms of rigidity, one should then
test for gegenhalten at the elbow by repeatedly extending
and flexing the arm, feeling carefully for any increasing
rigidity. Evidence for this generally indicates frontal lobe
damage.
Abnormal movements
Tremor (Section 3.1) is generally of one of three types: rest,
postural, or intention. Rest tremor is most noticeable when
the extremity is at rest, as for example when the patient is
seated with the hands resting in the lap. Postural tremor
becomes evident when a posture is maintained, as, for
example, when the arms are held straight out in front with
the fingers extended and spread. Intention tremor (as
described in Cerebellar testing, p. 13) appears when the
patient carries out an intended action, as, for example,
touching the index finger to the nose. Other forms are also
possible, for example, Holmes’ tremor, which has both
postural and intention elements. Tremor is further characterized
in terms of amplitude (from fine to coarse) and
frequency (ranging from slow [3–5 cps] to medium
[6–10 cps] to rapid [11–20 cycles per second, cps]).
Myoclonus (Section 3.2) consists of ‘a shock-like muscular
contraction’ (Brain 1964) and may be focal, segmental,
or generalized, occurring either spontaneously in
response to some sudden stimulus (e.g., a loud noise) or as
‘intention’ or ‘action’ myoclonus that appears upon intentional
movement. This is an especially valuable sign and
the physician should remain alert to its occurrence
throughout the interview and examination.
Motor tics (Section 3.3) are sudden involuntary movements
that, importantly, resemble purposeful movements,
such as shoulder shrugs, facial grimaces, or head jerks.
Unlike myoclonus, tics involve ‘a number of muscles in
their normal synergic relationships’ (Brain 1964).
Chorea (Section 3.4), according to Brain (1964), is
characterized by ‘quasi-purposive, jerky, irregular, and
non-repetitive’ movements that are very brief in duration,
generally erupting randomly on different parts of the body.
Athetosis (Section 3.5) ‘consists of slow, writhing movements’
(Brain 1964) that are generally most evident in the
distal portions of a limb; they are persistent and seem to
flow into one another in a serpentine fashion.
Ballismus (Section 3.6), which is generally unilateral,
consists of ‘wild flaillike, writhing, twisting or rolling movements
that may be intense and may lead to exhaustion’
(DeJong 1979). In severe cases the flinging movements of
the extremity may actually throw the patient off the chair
or bed.
Dystonia (Section 3.7), in contrast with ballismus, consists
of slow and sustained movements that variously twist
or contort the involved body part. It may be focal (e.g.,
moving the head to one side or ‘cramping’ the hand), segmental
(e.g., spreading to an adjacent body part, as with
the head turning and the shoulder elevating), or generalized
(e.g., in severe cases, creating a human ‘pretzel’).
Parkinsonism (Section 3.8), when fully developed,
stamps patients with a distinctive clinical picture. A flexion
posture is evident, with the patient being stooped over with
the arms and legs held in flexion, and a rhythmic ‘pill-rolling’
rest tremor of the hands may be seen, especially with the
hands resting on the lap. The face is often ‘masked’ and
expressionless, and bradykinesia is evident in the slowness
with which all movements are executed. Gait is shuffling
and one may also see festination wherein the patient seems
to hurry ‘with small steps in a bent attitude, as if trying to
catch up [with] his center of gravity’ (Brain 1964).
Akathisia (Section 3.10) is typified by an inability to
keep still. If standing, patients may rock back and forth or
‘march in place’ and, if seated, there may be a restless
fidgeting, with crossing and uncrossing of the arms or legs.
In severe cases, the compulsion to move is irresistible, and