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43

Section

The neurology of schizophrenia

2

Section 2

The neurology of schizophrenia

schizophrenia

Richard D. Sanders and Matcheri S. Keshavan
Facts box

Neurologic

examinations

of

people

with

schizophrenia differ from those of healthy peo-1. The neurological examination is important
ple, but the clinical implications of this are uncertain.

in the assessment of schizophrenia-like

The usual clinical purpose of the neurologic examina-psychoses.

tion in the psychotic patient is to rule out secondary or
2. In the clinical setting, it is conducted with
“organic” psychoses. This purpose has been obscured,
the assumption that abnormal findings will
if anything, by the wealth of data now demonstrating
suggest a secondary psychosis.

that neurologic signs are prevalent in the “functional”

3. Empirically, it has been studied with the
psychoses, so that their very presence cannot be taken
assumption that abnormal findings will

as evidence of additional neurologic disorder. Further,
suggest that idiopathic psychoses have a

we have very little data actually comparing neurologic
neurological base.

examination findings from patients with primary and
4. This review compares schizophrenia with
secondary psychoses. Thus, we are left with describing
secondary psychoses and with healthy

common findings in schizophrenia and the prevalence
comparison groups.

of abnormalities, providing content for the evaluation
5. Focus is on specific neurologic tests with
of individual patients, and allowing one to judge the
some localizing or pathologic significance.

likelihood that the case is primary or secondary.

This chapter focuses on “hard” much more than
“soft” signs. In this context, “hard” means “strongly
indicative of neurologic dysfunction at a specific loca-

tion or of a specific cause.” The term has been used
Schizophrenia and related conditions have long been
somewhat differently in some schizophrenia research
regarded as more neurologic or “organic” than other
[16, 17, 18].
Although “hard” signs individually are
psychiatric conditions such as mood, anxiety, and per-more persuasive than “soft” signs as evidence of dis-sonality disorders. Correspondingly, published stud-crete lesions, it is really the examination as a whole
ies of neurological examination in schizophrenia out-that provides hard or soft evidence of any particular
number those in other psychiatric disorders. These
pathology. Hard signs are included in many neurologic
studies virtually all conclude that there is an excess of
batteries
[19, 20, 21, 22]
but we cite data using these
abnormal or anomalous findings in schizophrenia
[1,

batteries only when the prevalence of specific signs is
2, 3, 4, 5, 6]
. That they are elevated at the onset of the
reported.

disorder
[7, 8, 9, 10, 11]
strongly suggests that they are
Although the topic of soft signs in schizophrenia
intrinsic features of the disorder, and not artifacts of
has been well-reviewed in recent years, the following
medication, institutionalization, or other epiphenom-will not greatly overlap with those papers [3, 4, 5, 6].

ena. Further, clinically recovered patients
[12, 13]
and
Even our more clinically oriented reviews of the neu-symptomatic high-risk subjects
[14, 15]
have elevated
rologic examination in schizophrenia
[23, 24]
have
rates of neurological examination abnormality, sug-not dealt extensively with the question of ruling out
gesting that neurological impairment is also not simply
secondary schizophrenia. Because the hard signs (as
a marker of active psychosis. Thus, it is apparent that
defined herein) have received less attention in recent
abnormal neurologic performance in schizophrenia is
publications, we tend to focus on older sources. We
47

prevalent and intrinsic to the disease.

also include some references to neuropsychological
The Neurology of Schizophrenia – Section 2

data, as some of these have included localizing tests
been described in 3% to 35%, hypoactivity in 14% to
[25].

15%, and asymmetry in 10 to 15% of patients with
schizophrenia. The variety of findings here may be
Review

partly attributable to the fact that clinical muscle-stretch reflex testing is not highly reliable
[35],
and
such studies are not easily blinded. Still, asymmetry
Reflexes

is the most diagnostically significant of these findings
Muscle stretch (deep tendon) reflexes can be aberrant
and has been found consistently at a fairly low fre-in three general ways: hypoactive, hyperactive, and
quency in primary schizophrenia.

asymmetric. Markedly hypoactive reflexes (includ-Pathological reflexes of pyramidal tract integrity
ing absent reflexes) are uncommon except in the
were of interest to some twentieth century researchers.

elderly, and most often indicate peripheral neuropa-The Babinski reflex was present in 1.4% of patients,
thy or hypothyroidism. Markedly hyperactive reflexes
more than in 0.6% of a comparison group; there were
(including clonus) are upper motor neuron signs, most
similar results for other related reflexes
[30].
Steck
often reflecting white matter disease or certain toxic–
(1923)
[36]
saw the toe rise in only 0.5% of patients
metabolic states. Markedly asymmetric reflexes are the
with schizophrenia. Quitkin and colleagues
[37]
noted
most localizing of these signs, usually reflecting an
a Babinski in 3.5% of their schizophrenic patients.

upper motor neuron lesion contralateral to the more
Chen and colleagues
[22]
found it in 6.8% of patients
active side.

and 5% in healthy controls, whereas Griffiths and col-Early descriptions and studies of dementia prae-leagues
[34]
found it in 5% on each side in patients
cox/schizophrenia included hyperactive deep tendon
but in no controls on either side. Unequivocal Babinski
(muscle stretch) reflexes
[26, 27, 28]
; indeed, Bleuler
and related reflexes are not common in schizophrenia.

[27,
p. 302] described them as “always exaggerated.”

Pathological nonlocalizing reflexes, often called
Out of 100 patients, Runeberg
[29]
found reflexes to
“frontal, release, primitive, or developmental,” usually
be hyperactive in 35% and hypoactive in 14%; asym-reflect diffuse impairment. Although intriguing, they
metry was “very frequent.” Among a series of 1,000

have limited utility in clarifying etiology or diagnosis
preneuroleptic cases, 11% had increased or decreased
[38, 39, 40].

reflexes, and 10% had asymmetric reflexes; less than
1% of 710 healthy college students had either type
of finding
[30].
Kennard (1960)
[31]
examined much
Motor strength
smaller numbers of adolescent state hospital patients
Hemiparesis can be obvious in the observation of gait
and found that those who were clinically diagnosed
(e.g. circumduction of the affected leg) or in reduced
as schizophrenic had less frequent reflex asymme-spontaneous use of the affected side. Strength testing
try (15%) than those diagnosed organic (35%). More
usually consists of bilateral comparisons, rather than
recently, diffusely brisk (but not frankly abnormal)
comparisons to external standards. Common upper
reflexes have again been noted in clinical examina-extremity tests include the pronator drift test, the arm-tion
[10,
32],
but do not discriminate schizophrenia
circling test, and the grip strength test. Drift was found
from mood disorders
[10].
Either hypoactive or hyper-in 12.9% of schizophrenic patients and not in healthy
active reflexes were found in 10.7% of patients, but
controls (p
=
0.0009), nearly significant, even after
none had asymmetry
[33].
Using what appeared to be
correcting for about 90 tests of significance
[13].
Fur-a more stringent standard for hyper-reflexia, another
ther, drift was found in a surprising 48% of patients
study found 3% in schizophrenia and 2% in controls
(no control group) in one series
[33].
Recent studies
[34].
Chen and colleagues
[22]
found 3% to 8% preva-found comparable grip strength in schizophrenia and
lence of hyper-reflexia in upper and lower limbs in
healthy comparison groups
[32, 41, 42].
Dynamome-schizophrenic patients and healthy controls, without
ter testing may find absolute differences (less power
significant group differences. Hypo-reflexia was non-in patients) but normal lateralization
[43].
Not sur-significantly more prevalent in the upper extremities
prisingly, schizophrenic patients were less likely to
(14.5% vs. 10%) and reached significance (ignoring
show abnormal strength inequalities than were a group
multiple tests of significance) in the lower extremi-of “organic” patients
[44]
. Pronator drift is appar-

48

ties (14.5% vs. 4%). In summary, hyperactivity has
ently not rare in schizophrenia, so it should not be
Chapter 4 – The neurologic examination in schizophrenia