Keywords: Hydrocephalus, normal pressure - translations - validation studies - surveys and questionnaires
Palavras-chave: hidrocefalia de pressão normal - traduções - estudos de validação - inquéritos e questionários
Normal pressure hydrocephalus (NPH) is a neurological disease characterized predominantly
by progressive development of gait apraxia, cognitive disturbances and urinary incontinence.
Other neuropsychiatric symptoms may also occur[1 ],[2 ],[3 ],[4 ],[5 ],[6 ],[7 ]. It promotes the patient's functional dependence and is responsible for family and
social burden[8 ],[9 ],[10 ],[11 ],[12 ],[13 ],[14 ],[15 ]. However, in many cases, symptoms may be mitigated with appropriate surgical treatment
and multidisciplinary neurocognitive rehabilitation[9 ].
Many scales are widely applied to evaluate NPH; however, most of them are not specific,
having been adapted from the evaluation of cognitive deficits (Mini Mental State Examination,
Cambridge Cognitive Assessment and Montreal Cognitive Assessment) and from motor evaluations
(Timed Up and Go, Dynamic Gait Index, Berg Balance Scale, and others)[1 ],[2 ],[3 ],[4 ],[5 ],[6 ],[7 ],[8 ],[9 ],[10 ],[11 ],[12 ],[13 ],[14 ],[15 ].
However, a specific scale has been developed to address all three components of the
triad. The Grading Scale for Idiopathic Normal Pressure Hydrocephalus was originally
developed in Japan in the English language, based on a cooperative study, between
1996 and 1999, to determine the most predictive diagnostic criteria for NPH patients[13 ]. It comprises three domains (gait, dementia and urinary incontinence) with scores
ranging from 0 to 12 (the higher the score, the worse the symptoms). It is easily
and rapidly applied and may be used as a follow-up evaluation tool, correlating with
post treatment symptoms and results[1 ].
The objective of the present study was to validate the Grading Scale for Idiopathic
Normal Pressure Hydrocephalus developed in English that was translated into Portuguese
as the Normal Pressure Hydrocephalus Patient Graduation Scale (NPHPGS).
METHODS
A cross-sectional, observational study was performed on 121 patients of both genders,
aged over eighteen years of age, with a medical diagnosis of NPH. Patients were recruited
by means of a consecutive sample, according to the following criteria.
Inclusion criteria
Patients with an idiopathic or secondary NPH diagnosis, older than eighteen years
of age, of both genders, who agreed to participate. The NPH diagnosis was considered
in patients with at least one of the constituent symptoms of the classic triad (urinary
incontinence, memory impairment, or gait apraxia), and evidence of hydrocephalus on
neuroimaging (CT or MRI).
Exclusion criteria
Patients with an altered level of consciousness, patients with clinically decompensated
systemic diseases or malignancies.
The present study was approved by the Ethics Committee for Analysis of Research Projects
of the Hospital das Clínicas of the Faculty of Medicine of the University of São Paulo.
Translation
The Grading Scale for Idiopathic Normal Pressure Hydrocephalus was translated into
Portuguese in a standardized way to guarantee the quality and reliability of the original
version, according to the method by Guillemin et al.[16 ].
Translation was carried out by two bilingual Brazilian neurologists, experienced in
the validation of instruments, and the two final translations were compared by the
translators, correcting the inconsistencies, and developing a consensual translation.
Afterwards, the back-translation to English was performed by two other bilingual neurologists,
who were different from the previous ones and did not know the original scale.
Additionally, a comparison of the versions was made by a multidisciplinary committee,
comprising physicians and physiotherapists who were not involved in the translation
process, defining the Portuguese version of the scale as “Escala de Graduação do Paciente
com Hidrocefalia de Pressão Normal” (the above-mentioned NPHPGS). This Portuguese
version of the scale is shown in [Figure 1 ].
Figure 1 Portuguese version of the Grading Scale for Idiopathic Normal Pressure Hydrocephalus[13 ] – the Normal Pressure Hydrocephalus Patient Graduation Scale.
Validation
Patients were individually evaluated at two different times, with a one-week interval.
Data were collected by physiotherapist A and, subsequently, by physiotherapist B,
sequentially evaluating the same patient. In this way, it was possible to compare
the results and avoid errors between observers. On the first day, the initial protocol
was determined, so that these results could be compared to test the reliability of
the new instrument containing personal data by application of the Functional Independence
Measure (FIM), Berg Balance Scale (BBS), Dynamic Gait Index (DGI), Timed Up and Go
(TUG) and the NPHPGS by physiotherapist A. On the same day, the second physiotherapist
B applied the NPHPGS to verify reproducibility between observers.
The TUG test evaluates the time taken to walk a short distance and has been proven
to be a good option for diagnosis, outcome prediction, and postoperative follow-up,
although there have been no studies of isolated TUG performance in the setting of
NPH[1 ],[17 ],[18 ],[19 ],[20 ],[21 ],[22 ].
The FIM is a scale that evaluates disability in neurological patients according to
their ability to perform routine daily personal activities, such as self-care, sphincter
control, mobility and locomotion, communication and social cognition[17 ],[18 ],[19 ],[20 ],[21 ],[22 ].
The DGI assesses an individual's ability to modify balance while walking, in the presence
of external demands. The test is performed with a marked distance of 20 feet and can
be performed with or without an assistive device. Eight tasks are graded on a score
from 0 to 3 (0, severe impairment; 1, moderate impairment; 2, minimal impairment;
3, no gait dysfunction), for a maximum score of 24. The eight tasks include 1) level
surface gait, 2) change in gait speed, 3) gait with horizontal head turns, 4) gait
with vertical head turns, 5) gait with pivot turn, 6) stepping over obstacles, 7)
stepping around obstacles, and 8) stair climbing[17 ],[18 ],[19 ],[20 ],[21 ],[22 ].
The BBS is one of the most widely-used and recognized balance measures. It has been
validated in several populations, including stroke, and cut-off scores have been determined
to identify those at risk of falls and those who need a gait aid for ambulation. It
is commonly applied during inpatient rehabilitation, and has been shown to predict
length of stay and discharge destination[17 ]
–
[22 ].
After one week, the patients underwent a new evaluation of the NPHPGS by the initial
physiotherapist A, to verify the intraobserver (test/retest) reproducibility.
RESULTS
A total of 121 patients were studied, with a higher percentage of male patients (60.33%).
The overall age range was between 35 and 92 years, with a higher concentration of
patients between 71 and 80 years. The mean age was 71.09 years with standard deviation
= 2.8 years. Primary NPH was present in 50 patients, while secondary NPH was present
in 71 patients (usually following meningitis, trauma or subarachnoid hemorrhage).
As for the domains, there was a higher frequency of gait impairment (96.69%), followed
by dementia (85.95%) and urinary incontinence (79.33%). The summary of results are
presented in the [Table ].
Table
Summary of results, with evaluation of correlation and observer agreement.
Variable
Statistical analysis
Cohen's Kappa coefficient for measuring agreement
Patients
Female (n)
38
Intraobserver
Interobserver
Male (n)
73
Gait
0.80
0.91
Mean age (years)
71
Dementia
0.90
0.86
Urinary incontinence
0.87
0.87
Symptoms (%)
Pearson's Correlation
Gait apraxia
96
NPHPGS and FIM
0.842
Dementia
85
NPHPGS and BBS
0.803
Urinary incontinence
79
NPHPGS and DGI
0.694
NPHPGS and TUG
0.557
FIM: Functional independence measure; BBS: Berg balance scale; DGI: Dynamic gait index;
TUG: Timed up and go; NPHPGS: Normal pressure hydrocephalus patient graduation scale.
To evaluate the reliability and reproducibility, the scale was applied by the same
evaluator with a one-week interval (intraobserver analysis) and different raters on
the same day (interobserver analysis). The results were analyzed by Cohen's Kappa
coefficient for measuring agreement. For intraobserver agreement, a general Kappa
value was obtained, with an excellent concordance for the gait items (0.80), dementia
(0.90) and incontinence (0.87).
Subsequently, an analysis of the validation of the method was carried out through
the interobserver agreement, with excellent agreement for the gait items (0.91), dementia
(0.86) and incontinence (0.87).
The comparison of the NPHPGS with the other scales was performed using Pearson's correlation
coefficient, followed by the hierarchy shown in the graphs obtained from the ANOVA
test values and multiple comparisons of the Tukey Test.
A satisfactory correlation was found in the NPHPGS and FIM scales, using Pearson's
correlation (0.842). The hierarchy was obtained according to NPH values: below 40,
between 40 and 79 and above 80 ([Figure 2 ]).
Figure 2 Correlation of data of the Portuguese NPHPGS and the FIM. Confidence interval = mean
± 1.96 * standard deviation / √ (n-1).NPHPGS: Normal pressure hydrocephalus patient
graduation scale; FIM: Functional independence measure;
A satisfactory correlation was found between the NPHPGS and BBS scores using Pearson's
correlation (0.803). The hierarchy was obtained according to the NPH values: below
36, between 36 and 45, and above 46 ([Figure 3 ]).
Figure 3 Correlation of data of the Portuguese NPHPGS and the BBS. Confidence interval = mean
± 1.96 * standard deviation / √ (n-1).NPHPGS: Normal pressure hydrocephalus patient
graduation scale; BBS: Berg balance scale.
A moderate correlation was found between the NPHPGS and DGI, using Pearson's correlation
(0.694). The hierarchy was obtained according to the NPH values: below 19, equal to,
or above 19 ([Figure 4 ]).
Figure 4 Correlation of data of the Portuguese NPHPGS and the DGI. Confidence interval = mean
± 1.96 * standard deviation / √ (n-1).NPHPGS: Normal pressure hydrocephalus patient
graduation scale; DGI: Dynamic gait index.
A moderate correlation was found between the NPHPGS and TUG, using Pearson's correlation
(0.557). The hierarchy was obtained according to NPH values: below 12, between 13
and 19, between 20 and 29, and above 30 ([Figure 5 ]).
Figure 5 Correlation of data of the Portuguese version of the NPHPGS Scale and the TUG. Confidence
interval = mean ± 1.96 * standard deviation / √ (n-1).NPHPGS: Normal pressure hydrocephalus
patient graduation scale; TUG: Timed up and go.
DISCUSSION
The lack of evaluation instruments aimed at NPH patients that have been translated
and validated for Portuguese may restrict the research in this field. We translated
and validated the Grading Scale for Idiopathic Normal Pressure Hydrocephalus. This
instrument was designed to quantify the degree of deficit in patients with NPH[13 ].
In the intraobserver evaluation, the agreement was 0.80 for gait, 0.90 for dementia
and 0.87 for urinary incontinence, all classified as excellent concordance. The same
classification was found for the interobserver evaluation, with 0.91 for gait, 0.86
for dementia and 0.87 for urinary incontinence. These results favor the use of the
evaluated instrument.
Although there is no gold standard for NPH evaluation, many scales have already been
developed and used in the literature to assess the severity of the NPH triad. However,
the main problem faced is the similarity between items in these domains, which often
hinders the interviewer's scoring.
Kubo[23 ] developed the grading scale for the evolution of NPH symptoms. However there has
been criticism regarding items in the cognitive domain that tended to dubiously score
amnesia, inattention and disorientation. In the gait domain, there was also an inconsistency
of classification, as the scale had a different classification for the imbalance item,
but without distinction of an objective gait disorder. Cordero Tous et al.[24 ] carried out a prospective study using clinical scales and radiological findings
to evaluate 40 patients with NPH. The items of the NPH scale in the cognitive domain
were confusing, including the vegetative state, severe dementia and personality changes,
which were difficult to stage and describe.
Owler et al.[25 ] described a modified scale for NPH for the clinical classification of patients.
However, this scale subjectively evaluated daily life activities, and sphincter domain
symptoms were only described as present or absent, which was also subjective and not
elucidating. Thus, the NPH evaluated in the study by Mori[13 ] seemed to be more objectively applied and complete.
Regarding the evaluation of the scores of the new NPHPGS, the scores compared with
other widely-used and validated scales. In the comparison with the FIM total score,
there was a high concordance of the findings, as the patients who presented with the
greatest impairment on the NPHPGS were concomitantly classified with greater impairments
in the FIM scale. Correlation was statistically satisfactory (-0.842). The same response
was observed for the BBS (-0.803), DGI (-0.694) and TUG (-0.557). The above results
confirm that the Grading Scale for Idiopathic Normal Pressure Hydrocephalus[13 ] and its Portuguese-validated version correlates with NPH symptoms and should be
applied to evaluate these patients.
In conclusion, the present study showed a statistically significant correlation between
the NPHPGS and the TUG, FIM, DGI and BBS. Additionally, the NPHPGS scale had also
satisfactory interobserver and intraobserver agreement in the analysis of scores in
the translated version. Thus, the Portuguese version is validated and may be used
in assessing NPH.
