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The results regarding specific diseases in this review were
based on data obtained during a 10 year study and have been
published in a Supplement to the American Journal of Physical
Medicine & Rehabilitation, Volume 74, Number 2, July/August
1995.
Testing was completed over the course of 1 or 2 days with
appropriate breaks, depending on the individual's endurance.
Participation was voluntary, and all participants signed a
consent form outlining the evaluation protocol as approved
by a University Human Subjects Committee. Extremely deviant
results were judged on an individual basis and excluded from
the study if an individual's degree of physical impairment
might invalidate test scores. Tests were administered according
to standardization by a trained psychometrist under the supervision
of a licensed psychologist.
The Wechsler Adult Intelligence Scale-Revised (WAIS-R) and
the Wechsler Intelligence Scale for Children-Revised (WISC-R)
were used to assess intellectual ability. Selected scales
of the Halstead-Reitan Neuropsychological Test Battery (HRB)
were administered to evaluate neuropsychologic functions.
Previous experience with the HRB suggested that subtle physical
impairments may have negatively affected test results. Therefore,
the Category Test, Seashore Rhythm Test, and Speech-Perception
Test were also used, because performance on these instruments
is not dependent on motor function. The Trailmaking Tests,
although requiring some manual manipulation, were retained
for their diagnostic sensitivity to organicity. For individuals
between the ages of 9 and 14, test administration and scoring
followed the guidelines for the HRB for Children. Results
from the WAIS-R, WISC-R, and HRB tests were compared with
reference standards. Means and standard deviations (SD) for
standardized scaled norms are 100 +/- 15 and 10 +/- 3 on the
subtests of the WAIS-R and WISC-R. Standardized T scores for
the WAIS-R, WISC-R, and HRB were obtained by applying demographic
corrections for age, gender, and education. Means and SDs
for T-scores are 50 +/- 10. T scores less than 2 SDs below
the mean were used in most of the data analysis since scores
30 or less are considered as an indicator of clinical impairment,
according to suggested scoring criteria. Only 2% of the population
have T scores in this range while 14.6% have T scores less
than 1 SD below the
mean ( 40). In most of the diseases, longitudinal evaluations
were obtained in a sample of the individuals to evaluate any
changes with age and disease duration.
The Minnesota Multiphasic Personality Inventory (MMPI), the
California Psychological Inventory (CPI), the Suicide Probability
Scale (SPS) and the Ability Testing Depression Scale (IPAT-D)
were administered to individuals greater than 17 years to
assess personality adjustment. The MMPI is a widely used measure
of general psychopathology. The IPAT-D is a self-report measure
of depression. The SPS is used to assess suicide risk and
includes subscales assessing hopelessness, suicide ideation,
negative self-evaluation and hostility. The CPI is a widely
used measure of personality and normal psychological functioning.
Only selected items from these tests are included in this
review. In children with DMD, the Personality Inventory for
Children (PIC) and the Peabody Individual Achievement Test
(PIAT)) were used. According to suggested scoring criteria,
MMPI, SPS, and PIC scores that are greater than 2 SDs above
the mean T-score (70 or more) were considered to be elevated
and indicative of possible clinical importance. CPI scores
that are less or more than 2 SDs from the mean (30 or less,
70 or more) were considered to be clinically significant.
IPAT-D are stanine scores. A score greater than 9 is equivalent
to 2 SD. As with intelligence tests, only 2% of the population
have T scores in these ranges. Individuals with Congenital
Myotonic Muscular Dystrophy were not evaluated since severe
cognitive deficits generally precluded their ability to respond
meaningfully to self-report measures.
Caution should be used in the evaluation of test results,
especially those measuring intellectual ability and neuropsychologic
function. Statistical interpretations based on group mean
scores do not necessarily portray accurately the status of
any individual. Individual scores that deviate more than 2
SDs from the mean, and even 1 SD in some tests, call for additional
focused evaluation and follow-up.
Intellectual Ability.
With the exception of a few differences, the Spinal Muscular
Atrophy (SMA), Facioscapulohumeral Dystrophy (FSHD), Limb-Girdle
Syndrome (LGS), Hereditary Motor Sensory Neuropathy (HMSN),
and Becker's Dystrophy (BMD) groups had similar scores on
the WAIS scales. Verbal, Performance, and Full Scale Group
IQ scaled scores were well within 1 SD (15) of the mean (100)
for each disease (Table 1). Only
FSHD (8%) and LGS (14%) had T scores less than 2 SDs below
the mean for Verbal and Full Scale IQs. With all 5 diseases
considered as a single group, the Full Scale IQ was 104 13
and only 2% had T scores less than 2 SDs below the T score
mean.
IQ subtest results are reviewed in Table
2. In the five disease groups, the only major difference
was between LGS and the other four diseases. LGS had T scores
less than 2 SDs below the mean on seven of the 11 Verbal and
Performance subtest items. Scores were, however, only 4% to
7% lower. For all five diseases combined, Arithmetic was the
only item to fall below the 2 SD level at 6%.
There was no difference between Verbal and Performance IQ
in any of the five disease groups indicating that upper extremity
weakness, even moderate to severe hand weakness in HMSN individuals,
does not affect manual testing. Longitudinal assessments of
intellectual ability and neuropsychological function for three
or more years in 14 SMA, 4 FSHD, 6 LGS and 9 HMSN individuals
indicated that intellectual and cognitive functions were stable
over time. The only other studies relating to intellectual
ability and neuropsychologic function showed mixed results.
Karagan and Sorensen (Neurol 31:448, 1981), reported that
some individuals with BMD, LGS, and FSHD had significant impairment
of Verbal Scale IQs. Portwood et al (Arch Phys Med Rehabil
67:299, 1986) did not find any evidence of cognitive defects
in LGS and FSHD.
Clinical impairment was greatest in Congenital Myotonic Dystrophy
(C-MMD), and to a lesser extent in Non-Congenital Myotonic
Dystrophy (NC-MMD), Hereditary Spinal Cerebellar Ataxia (HSCA),
and Duchenne Muscular Dystrophy (DMD). Analysis showed that
Verbal, Performance and Full Scale IQs in these four diseases
were significantly lower than IQs for SMA, FSHD, LGS, HMSN
and BMD. Seventy to 90% of the WAIS subtests were also significantly
lower.
Verbal, Performance, and Full Scale IQ mean scores were significantly
below the population means in C-MMD (Table
1). T scores less than 2 SDs below the mean were 38% for
Verbal and Performance IQ and 25% for Full Scale IQ, and 50%
to 75% fell below 1 SD. T scores on all subtest items were
13% to 50% less than 2 SDs below the mean and 50% to 100%
less than 1 SD below the mean (Table
2). There was no clear cut pattern of involvement, but
the lowest scores were in Arithmetic and Object Design and
the highest scores in Similarities and Picture Completion.
These results are similar to other reports (Calderon: J Pediatrics
68:423, 1966; Vanier: British Med J 2:1284, 1960; Portwood:
Arch Phys Med Rehabil 65:533, 1984). There was no difference
between Verbal and Performance IQ scores. Longitudinal evaluations
(WAIS, WISC and HRB) for five or more years in 6 individual
indicated that intellectual and neuropsychological functions
were stable over time.
Verbal, Performance, and Full Scale IQ mean scores in NC-MMD
were within the population means but at the lower end of the
IQ range, below scores for SMA, FSHD, LGS, HMSN, and BMD,
and above those for C-MMD (Table 1).
T scores less than 2 SD below the mean were 16% Verbal, 5%
Performance and 11% Full Scale IQ. However, 25% Verbal, 35%
Performance and 30% Full Scale IQ T scores were less than
1 SD below the mean. T scores on sub test items ranged from
0% to only 8% less than 2 SDs below the mean, but 22% to 65%
less than 1 SD below the mean (Table
2). There was no specific pattern although other investigators
have reported impairment in visual spatial and construction
abilities and alteration of language and memory (Censori:
J Neurol 237:251, 1990). Our results are more consistent with
other reports of generalized cognitive impairment (Bird, et
al: J Neurol Neurosurg Psych 46:971, 1983; Portwood et al:
Arch Phys Med Rehabil 67: 299, 1986; Portwood et al: Arch
Phys Med Rehabil 65: 533, 1984; Stuss et al: J Clin Exp Neuropsychol
9: 131, 1987). There was no difference between Verbal and
Performance IQ. No deterioration was found in intellectual
ability and neuropsychological function in 23 individuals
tested longitudinally for five or more years. This observation
is similar to the results of other studies (Bird et al: J
Neurol Neurosurg Psychiatry 46: 971, 1983; Rosman: Neurol
20:329, 1970; Stuss et al: J Clin Exp Neuropsychol 9:131,
1987). Although NC-MMD individuals scored at the lower end
of the normal range of intelligence, the difference between
C-MMD and NC-MMD was marked.
DMD had the second lowest IQ profile. Verbal, Performance
and Full Scale IQ mean scores were significantly below the
population means (Table 1). T scores
less than 2 SDs below the mean were 9% Verbal IQ, 6% Performance
IQ, and 9% Full Scale IQ, but 45% to 51% fell below 1 SD on
the T score means. T scores in sub test items ranged from
0% to 15% less than 2 SD below the mean T scores (Table
2). Arithmetic was the lowest verbal subscale score and
coding the lowest performance scale score, but there was no
specific pattern of involvement. To investigate the possibility,
raised by other investigators (Miller: Brain Dev 7:7, 1985;
Sollee: J Clin Exp Neuropsychol 7:486, 1985), of an early
verbal deficit that is overcome in later years, DMD boys were
reviewed in two age groups; 6-9 and 14-17 years old. Differences
were not statistically significant, although younger subjects
scored lower in Verbal IQ than older individuals.
Stability of intellectual function was assessed in 10 boys
with longitudinal testing over 3 years since some investigators
have reported that impairment becomes more severe with age
(Dubowitz: Arch Dis Childhood 40:296, 1965; Black: J Psychol
84:333, 1973). In this study, there was no significant change
in intellectual and neuropsychological function over time
as previously reported by Ogasawara (Am J Mental Retardation
93:544, 1989, and Worden and Vignos (Pediatrics 29:968, 1962).
In general, results indicated a mild global deficit although
a relative verbal deficit was found in younger individuals.
However, there was no significant differences between Verbal
and Performance IQ of the group as a whole. While the significance
is unknown, this has been also reported in previous studies
(Sollee et al: J Clin Exp Neuropsychol 7:486, 1985; Dorman
et al: Devel Med Child Neurol 30: 316, 1988; Marsh and Munsat:
Arch Disease Childhood 49:118, 1974). The relatively lower
scores in arithmetic (measure of reasoning ability and numerical
accuracy involving concentration and attention) and coding
(measure of visual-motor coordination, speed of mental operation
and short term memory) in the study were also found in other
investigations (Whelan: Dev Med Child Neurol 29:212, 1987;
Ogasawara: Am J Mental Retard 93:544, 1989, Karagan et al:
J Nervous and Mental Dis 168:419, 1980; Anderson et al: Devel
Med Child Neurol 30: 328, 1988). Although this and other studies
(Karagan: Psychol Bull 86:250, 1979; Dubowitz: Arch Dis in
Childhood 40: 296, 1965; Karagan et al: Devel Med Child Neurol
20: 435, 1978; Black: J Psychol 84:333, 1973; Worden and Vignos:
Pediatrics 29: 968, 1962) have shown mildly impaired function
in individuals with DMD, it should be noted that the range
includes individuals in the average and above average range.
Results on the school achievement test, PIAT, which evaluates
Math, Cognition, Spelling, and General Information, were similar
to results on the WAIS-R scale. Individuals scored the lowest
on mathematics and general information.
Performance and Full Scale IQ mean scores were also significantly
below the population means in HSCA whereas Verbal IQ was within
the normal range (Table 1). While
T scores less than 1 SD below the mean were 75% in Performance
and Full Scale IQ and 46% in Verbal IQ, there were no individuals
with scores less than 2 SD below the mean. T scores on sub
test items ranged from 8% to 17% less than 2 SD below the
mean but only for Information, Similarities, Object Design,
and Digit Symbol (Table 2). Using
T scores less than 1 SD below the mean, the greatest involvement
was in the Performance IQ sub tests. Longitudinal testing
in four individuals for 3 or more years did not show any change.
The significant difference between Verbal and Performance
IQ indicates that severe upper extremity ataxia probably affects
test execution whereas hand and arm weakness does not.
Neuropsychologic
Function.
As with intellectual ability, the SMA, FSHD, LGS, HMSN, and
BMD groups had similar results on the HRB items, with a few
exceptions (Table 2). Based on T
scores less than 2 SD below the mean, LGS had the highest
percent of involvement in the Category Test (18%), SMA the
highest percent involvement in the Trails A and B tests (13%),
and FSHD the highest percent of involvement in the Seashore
Rhythm (8%) and Speech Sounds (17%) tests. With all 5 diseases
combined as a single group, the only major impairment was
in the Category Test (10%) which measures logical reasoning
and concept formation. However, analysis showed that there
was a significant difference in 60% to 80% of the HRB items
between these 5 diseases and C-MMD, NC-MMD, DMD and HSCA.
In C-MMD, impairment in all of the HRB items was profound,
ranging from 33% to 67% with T scores less than 2 SD below
the mean (Table 2). Impairment with
scores less than 1 SD below the mean ranged from 80T to 100%.
The greatest percent of involvement was in the Category and
Tract B tests. This observation is not surprising, since laboratory
and autopsy findings have shown pathological central nervous
system involvement (Harper: Myotonic Dystrophy, WE Saunders,
1979.)
Evidence for neuropsychologic involvement in some individuals
was also found in NC-MMD. T scores less than 2 SDs below the
mean ranged from a low of 9% in the Seashore Rhythm test to
21% in the Trails B test, and scores 1 SD below the mean ranged
from 55% in the Speech Sounds test to 24% in the Seashore
Rhythm test.
In DMD, there was impairment ranging from 8% to 33% with T
scores less than 2 SDs below the mean and 17% to 58% with
T scores less than 1 SD (Table 2).
There were no specific areas of strength or weakness indicating
a relatively mild general global deficit. As with intellectual
ability there was considerable variation between individuals.
Evidence for neuropsychological impairment in HSCA was also
observed. T scores less than 2 SDs below the mean ranged from
0% to 33%, and scores 1 SD below the mean ranged from a low
of 33% in the Seashore Rhythm and Category tests to 100% in
the Trails A test. These and the intellectual ability results
are not surprising since HSCAs are primarily diseases of the
central nervous system.
Other neuromuscular disorders not included in this study reported
to have neurophysiological impairment are some of the congenital
muscular dystrophies (Egger et al: Dev Med. Child Neurol 25:32,
1983) and ALS (David and Gillham: Psychometrics 27:441, 1986).
Personality and Psychosocial
Adjustment
All individuals evaluated with the MMPI, CPI, IPAT-D, and
the SPS were adults. Only selected items from the tests are
reported in this review. C-MMD and DMD were not included.
Based upon the mean SD T scores, there were no differences
between SMA, FSHD, LGS, HMSN, BMD, NC-MMD, and HSCA on any
of the MMPI, IPAT-D, and SPS items. On the CPI, however, there
were differences between NC-MMD and/or HSCA and the other
5 diseases. The NC-MMD group has scores significantly lower
than those for SMA, FSHD, LGS, HMSN and BMD in Sociability,
Sense of Well-being and Socialization (also in items not included
in this review--Capacity for Status, Self Control, Tolerance,
Good Impression, Intellectual Efficiency, Psychological Mindedness,
Flexibility, and Achievement via Conformance). The HSCA group
had significantly lower scores for sense of Well Being, Responsibility
and Socialization (also in terms not included in this review--Self
Control, Tolerance, Communality,
Achievement via Conformance and Independence, and Intellectual
Efficiency).
Table 3 reviews the percent for
each test item 2 SDs above or below the T score mean. Using
an arbitrary cut-off, individuals with HSCA scored 25% or
more 2 SDs above or below the T score mean in Hypochondriases,
Hysteria, Schizophrenia, Well-Being, Depression, Social, Socialization,
and Responsibility. The range was 36% to 63%. The MMPI profile
represents the characteristics of individuals who are dissatisfied,
depressed, worried and pessimistic, and suggests tendencies
toward timidity, aloofness and discouragement. The CPI profile
suggests a personality characterized by aloofness, passivity,
suspiciousness, lack of ambition, forgetfulness and irresponsibility.
Individuals with NC-MMD scored 25% or more 2 SDs above or
below the mean in Hysteria, Depression, Schizophrenia, Well-Being,
and Sociability. The range was 25% to 41%. The only other
disease with 5 or more test items 25% or more 2 SDs from the
mean was SMA, with a range of 25% to 62%; Hypochondriases,
Hysteria, Depression, Schizophrenia and Repression. Other
diseases had only 2 or 3 characteristics.
The personality characteristics of adults with SMA, FSHD,
LGS, HMSN, BMD, NC-MMD, and HSCA combined indicate differences
for test items such as Hypochondriases, Hysteria, Schizophrenia,
and Depression, primarily in degree. Also, five of the other
test items in Table 3 were present
12% to 21% 2 SDs from the mean T scores: Well Being, Responsibility,
Social, Sociability, and Socialization. In general, adults
with these neuromuscular diseases have the characteristics
of individuals who are dissatisfied, worried, pessimistic,
aloof, timid, and shy, anxious, discouraged, confused, awkward,
passive, suspicious, and cautious, and show lack of ambition.
The greater than normal endorsement of items, such as hypochondriases,
reflecting physical symptoms is more likely an indication
of their disability status than a reflection of psychological
coping style. This pattern probably represents a more generic
reaction to the presence of a chronic progressive disease.
Nineteen DMD boys were evaluated with the PIC and 21 with
the PIAT. On the PIC, 50% or more scored above 1 SD for frequency
(53%) , adjustment (58%), and development (68%). The frequency
scale identified atypical responses across many categories
while the adjustment scale is a general measure of psychological
adjustment. The development scale is a measure of physical
and intellectual development. The factor scales of the PIC
also suggested the presence of psychosocial problems among
some DMD boys. Twelve percent scored above 1 SD in Factor
1, 31% on Factor 2, 12% on Factor 3, and 88% on Factor 4.
The results of these Factor tests indicate that 12% to 31%
of DMD boys have the characteristics of impulsivity, problematic
anger, poor peer relations, limited conscience development,
poor peer relations and school behavior, sad affect, shyness,
peer rejection, social isolation, worry, poor self-concept,
insecurity, and somatization. Almost 90% had problems with
adaptive behavior, academic skills, motor coordination and
developmental delay.
These results are similar to those reported by other investigators
(Charash: Psychosocial Aspects of Muscular Dystrophy and Allied
Diseases, 1983; Madorsky: Arch Phys Med Rehabil, 64: 186,
1983). As with adults, certain elevated scores on the personality
inventory may actually represent a realistic self-appraisal
of the individual's physical status when including questions
relating to motor function, developmental delay, and social
and behavioral independence. This emphasizes the fact that
personality scales developed for and normalized on a nondisabled
population should be used with caution on a physically disabled
population. Some individuals, however, would clearly benefit
from referral for psychological evaluation and counseling.
Summary:
This research indicates that factors affecting personality
and adjustment need to be addressed and that interventions
should be developed that might reduce their accompanying emotional
distress. Possible treatments would include psychological
and/or pharmacological intervention for depression, help for
parents in dealing with guilt, motivation towards employment,
development of structured employment paths, and self-help
or support groups. The information presented has implications
for educators, counselors and vocational rehabilitation personnel
who are in a position to advise individuals with neuromuscular
diseases regarding educational and career objectives.
