OBJECTIVES—Little is
known about factors influencing the spread of blepharospasm to other
body parts. An investigation was carried out to deterrmine whether
demographic features (sex, age at blepharospasm onset), putative
risk, or protective factors for
blepharospasm (family
history of dystonia or tremor, previous head or face trauma with loss
of consciousness, ocular diseases, and cigarette smoking), age related
diseases (diabetes, hypertension), edentulousness, and neck or trunk
trauma preceding the onset of
blepharospasm could
distinguish patients with
blepharospasm who had
spread of dystonia from those who did not.
METHODS—159
outpatients presenting initially with
blepharospasm were
selected in 16 Italian Institutions. There were 104 patients with
focal
blepharospasm (mean
duration of disease 5.3 (SD 1.9) years) and 55 patients in whom
segmental or multifocal dystonia developed (mainly in the cranial
cervical area) 1.5 (1.2) years after the onset of
blepharospasm.
Information was obtained from a standardised questionnaire administered
by medical interviewers. A Cox regression model was used to examine the
relation between the investigated variables and spread.
RESULTS—Previous head
or face trauma with loss of consciousness, age at the onset of
blepharospasm, and
female sex were independently associated with an increased risk of
spread. A significant association was not found between spread of
dystonia and previous ocular diseases, hypertension, diabetes, neck or
trunk trauma, edentulousness, cigarette smoking, and family history of
dystonia or tremor. An unsatisfactory study power negatively influenced
the validity and accuracy of the negative findings relative to
diabetes, neck or trunk trauma, and cigarette smoking.
CONCLUSIONS—The
results of this exploratory study confirm that patients presenting
initially with
blepharospasm are most
likely to experience some spread of dystonia within a few years of the
onset of
blepharospasm and
suggest that head or face trauma with loss of consciousness preceding
the onset, age at onset, and female sex may be relevant to spread. The
suggested association between edentulousness and cranial cervical
dystonia may be apparent because of the confounding effect of both age
at onset and head or face trauma with loss of consciousness. The lack
of influence of family history of dystonia on spread is consistent with
previous findings indicating that the inheritance pattern is the same
for focal and segmental blepharospasm.
