Keywords:
Frontotemporal Dementia - Frontotemporal Lobar Degeneration - Aphasia - Dementia -
Diagnostic Errors - Neuropsychiatry
Palabras claves:
Demencia Frontotemporal - Degeneración Lobar Frontotemporal - Afasia - Demencia -
Errores Diagnósticos - Neuropsiquiatría
INTRODUCTION
Frontotemporal dementia (FTD) is one of the most common causes of dementia in people
under 65 years of age, and the third most prevalent cause of dementia altogether[1].
Clinically, the FTD syndromes include the behavioral variant of FTD (bvFTD) and two
language syndromes, the semantic (svPPA) and the nonfluent/agrammatic (nfvPPA) variants
of primary progressive aphasia. Between these FTD syndromes, bvFTD is the most common
clinical presentation. It is characterized by personality changes with behavioral
disinhibition, apathy, loss of empathy, compulsive or ritualistic behavior, hyperorality,
and dysexecutive symptoms[2]. In the language variants, the key component is progressive aphasia.
Unlike other dementias, such as Alzheimer's disease, FTD mainly affects behavior,
language, or the motor system. Due to these characteristics, it is often misdiagnosed
as a primary psychiatric illness[3]. Importantly, misdiagnosis has a negative impact on patients and their families
who seek an answer to symptoms that continue to progress, compromising the patient's
personality, isolating them from social ties, undermining the family economy, and
further disorienting the professionals who do not know how to deal with this disease.
To support proper diagnosis, many workgroups have evaluated potential reasons for
the diagnostic delay of FTD[4],[5],[6]. One study evaluated the mean duration from the onset of symptoms to the diagnosis
of a neurodegenerative disorder in each of the FTD syndromes (3.7 years for bvFTD,
3.5 years for nfvPPA, and 1.4 for svPPA)[7]. The authors concluded the reasons behind this delay to be related to a misdiagnosis,
with the symptoms of FTD being misattributed to a primary psychiatric disorder[3],[4].
Furthermore, we suspect that diagnosis errors could be even more important in Argentina
and the surrounding region. For example, the estimated prevalence of FTD in the US
for the population between 45 to 64 years is 15-22 per 100.000[8]. Based on these rates, Argentina (a country with approximately 10,040,258 inhabitants
in that age range[9]), should have a prevalence of 1,500 to 2,200 FTD cases. However, Argentina does
not maintain an active countrywide registry of these cases, so no reliable epidemiological
information regarding FTD exists. Fleni, situated in Buenos Aires, is one of the largest
neurology tertiary referral centers in Argentina in which more than 1000 patients
with dementia are evaluated annually and clinical care is integrated with extensive
research programs. Despite this, Fleni has identified only 50 patients with FTD from
its records from 2010 to the present day, likely representing an underestimation.
In the literature, it is well recorded that the given prevalence varies from country
to country and even in the same country from one study to another[7],[8],[10],[11],[12],[13]. The main reason for this is that this disease is still missed and misdiagnosed
and most numbers probably underestimate its true prevalence[4]. However, even if we ignore this fact and accept the estimated cases for this prevalence
numbers, the recorded cases in Argentina seem to be below what we would estimate.
Based on these arguments and considering the prevalence and the frequent misdiagnosis,
one possible explanation is that health professionals lack important knowledge regarding
FTD and thus may fail to diagnose it in its early stages. Given this, it is essential
to assess FTD knowledge among health professionals. To accomplish this, Wynn et al.
developed the Frontotemporal Dementia Rating Scale (FTDKS). In this 18-item scale,
the respondents answer objective questions about FTD using a 4-point Likert scale
format (False, Probably False, Probably True, True), with an auxiliary “I don’t know”
option.
To understand the low frequency of FTD diagnosis in Argentina, our intention was to
assess disease knowledge among health professionals. As a first step, we adapted the
FTDKS scale into Spanish and report on its psychometric properties.
METHODS
Cross-cultural adaptation process
In order to initiate the adaptation to Spanish and validation of the FTDKS, we first
asked for and obtained consent from the original author of the scale (Wynn et al.).
Following established guidelines[14], adapting the FTDKS to Spanish involved four-steps: the forward translation, the
blind back translation, a review by an expert committee, and administration to a validation
sample.
Forward translation
The first stage in the adaptation process was translating the FTDKS into Spanish.
A bilingual experimental psychologist from Argentina, familiar with both cultures,
translated the survey into Spanish.
Blind back translation
A second independent translator, a clinician with the source language (English) as
their mother tongue and who was blind to the original version, translated the scale
back into English. This process revealed that the Spanish (translated) and English
(original) versions reflected the same content.
Expert committee
A committee composed of a cognitive neurologist, neuropsychiatrist, neuropsychologist,
and the two translators who performed the initial translation and backward translation
assessed semantic, idiomatic, and conceptual equivalence of the Spanish FTDKS.
Final version
The final FTDKS Spanish version ([Table 1]), like the original version, consists of 18 items where respondents answer factual
questions about FTD using a 4-point Likert-type scale format (False, Probably False, Probably True, True), with an auxiliary Don’t Know option. Respondents receive 2 points for a correct True or False response, 1 point for a correct Probably True or Probably False response, and 0 points for an incorrect or Don’t Know response.
Table 1
Psychometric properties of the scale’s items. The statement column represents the
final form of the translated item. In parenthesis, the original version following
the correct answer.
|
Item
|
Statement
|
Mean
|
Standard deviation
|
Skew
|
Item difficulty
|
Item discrimination
|
A if deleted
|
|
1
|
La Demencia Frontotemporal (DFT) es una variante de la Enfermedad de Alzheimer (Frontotemporal
dementiais a type of Alzheimer disease) (F)
|
1.66
|
0.68
|
-1.77
|
0.83
|
0.39
|
0.72
|
|
2
|
Para la mayoría de las personas con DFT los síntomas aparecen antes de los 65 años
de edad (For the majority of people with frontotemporal dementia, symptoms appear
before they are 65 years old) (T)
|
1.25
|
0.85
|
-0.5
|
0.62
|
0.32
|
0.72
|
|
3
|
Entre todas las personas con demencia, un 5 a 10% de ellos tiene demencia frontotemporal
(Among all people with dementia, 5-10% of them have frontotemporal dementia) (F)
|
0.31
|
0.65
|
1.87
|
0.16
|
0.02
|
0.74
|
|
4
|
Las personas que rondan los treinta años de edad pueden tener demencia frontotemporal
(People in theirthirties can developsymptomsof frontotemporal dementia) (T)
|
0.9
|
0.84
|
0.2
|
0.45
|
0.21
|
0.73
|
|
5
|
La pérdida de memoria es un problema mayor en la demencia frontotemporal (Memory loss
is a major symptom of frontotemporal dementia) (F)
|
1.37
|
0.86
|
-0.81
|
0.69
|
0.32
|
0.72
|
|
6
|
La demencia frontotemporal puede ser transmitida genéticamente de los padres a los
hijos (Frontotemporal dementia can be passed down from parent to child) (T)
|
0.87
|
0.84
|
0.24
|
0.44
|
0.30
|
0.73
|
|
7
|
Dentro de las personas menores de 60 años de edad, la demencia frontotemporal es tan
común como la enfermedad de Alzheimer (Among people under 60 y old, frontotemporal
dementia is about as common as Alzheimer disease) (T)
|
0.63
|
0.82
|
0.77
|
0.32
|
0.28
|
0.73
|
|
8
|
Los estudios de neuroimagenes (tomografía y/o resonancia magnética) pueden por sí
solos decir si una persona tiene demencia frontotemporal (The results of a brain scan
by itself can tell you whether a person has frontotemporal dementia) (F)
|
1.39
|
0.87
|
-0.85
|
0.69
|
0.3
|
0.73
|
|
9
|
La personas con demencia frontotemporal tienen mejor desempeño cuando deben elegir
entre varias opciones predefinidas (People with frontotemporal dementia do best when
given choices among many options) (F)
|
0.84
|
0.92
|
0.33
|
0.42
|
0.23
|
0.73
|
|
10
|
Existen tratamientos para disminuir la velocidad de progresión de la demencia frontotemporal
(There are treatments to slow down frontotemporal dementia) (F)
|
0.76
|
0.87
|
0.49
|
0.38
|
0.38
|
0.72
|
|
11
|
Luego de que aparecen los primeros síntomas de demencia frontotemporal, la expectativa
de vida media es de 7 a 13 años (After symptoms of frontotemporal dementi aappear,
the average life expectancy is 7 to 13 years) (T)
|
1.09
|
0.85
|
-0.17
|
0.54
|
0.27
|
0.73
|
|
12
|
Basándose en la edad, es más probable que desarrollen demencia frontotemporal las
personas que rondan los 70 años de edad en comparación con las personas que rondan
los 50 años (On the basis of their age, people who are 70 years old are more likely
to develop frontotemporal dementia than people who are 50 years old) (F)
|
1.05
|
0.91
|
-0.1
|
0.53
|
0.52
|
0.70
|
|
13
|
En línea general los cuidadores de personas con demencia frontotemporal reportan mayores
niveles de estrés que los cuidadores con otras formas de demencia (On average, caregivers
of people with frontotemporal dementia report more stress than caregivers of people
with other dementias) (T)
|
1.43
|
0.75
|
-0.88
|
0.71
|
0.20
|
0.73
|
|
14
|
Las medicaciones diseñadas para mejorar la cognición y memoria en personas con Alzheimer
son también apropiadas para personas con demencia frontotemporal (Medications designed
to improve memory and thinking in people with Alzheimer disease are also appropriate
for people with frontotemporal dementia) (F)
|
1.02
|
0.9
|
-0.04
|
0.51
|
0.40
|
0.72
|
|
15
|
Las variantes del lenguaje de la demencia frontotemporal son más comunes que la variante
conductual (The language variant of frontotemporal dementia is more common than the
behavioral variant) (F)
|
1.22
|
0.85
|
-0.43
|
0.61
|
0.43
|
0.71
|
|
16
|
Los pacientes con la variante conductual de la demencia frontotemporal suelen tener
dificultad en evocar eventos del pasado (People with the behavioral variant of frontotemporal
dementia have difficulty remembering events from the past (F)
|
1.19
|
0.89
|
-0.38
|
0.59
|
0.43
|
0.71
|
|
17
|
Las personas con la varianteconductual de la demencia frontotemporal en general carecen
de interés en las cosas que antes disfrutaban (People with the behavioral variant
of frontotemporal dementia lack interest in things they used to find enjoyable) (T)
|
1.58
|
0.66
|
-1.32
|
0.79
|
0.20
|
0.73
|
|
18
|
Las personas con las variantes del lenguaje de la demencia frontotemporal son capaces
de leer y escribir sin dificultad (People with the language variant of frontotemporal
dementia are able to read and write without difficulty) (F)
|
1.22
|
0.88
|
-0.46
|
0.61
|
0.32
|
0.72
|
F: false statement; T: true statement.
Validation Sample
The final version of the Spanish FTDKS, along with a demographic questionnaire, was
distributed in a Google Forms format among health professionals using snowball sampling
techniques. The survey was distributed among colleagues using social networks and
email, both directly and using professional groups from the leading Argentine societies
of health professionals. In this way, 134 responses were obtained exclusively from
health professionals (neurologists, psychiatrists, clinical psychologists, and neuropsychologists).
In addition to responses to the Spanish version of the FTDKS, demographic data was
collected including: age, sex, education, professional discipline/specialty, years
of experience, academical or research activities, health system where they work (public
or private), practice settings, number of patients seen per month, self-reported knowledge
of FTD (prior to answering the FTDKS), and clinical experience with dementia.
Results were analyzed to obtain a global Cronbach’s α value. An isolated item analysis
was performed to determine skewness, item difficulty, item discrimination, and global
α if the item is deleted.
The item difficulty evaluates the proportion of respondents who answer an item correctly.
The item discrimination indicates how well an item discriminates respondents’ knowledge. A high discrimination
index indicates that the item works differently between respondents with higher and
lower scores, suggesting that the item identifies respondents with more or less knowledge
The statistical analysis was performed using R version 4.0.0 “Arbor day” and the Psych[15], sjPlot[16], and [Table 2] packages[17].
RESULTS
Sample characteristics
One hundred thirty-four health professionals completed the Spanish version of the
FTDKS. There were no reported difficulties in understanding the instructions or in
completion of the scale.
The sample characteristics are shown in [Table 2]. The mean age was 42.9 years (range = 25-77 years). Most of the professionals were
highly educated and trained, with 80 (59.7%) having finished at least the residency
and 82 (61.2%) having 8 or more years of clinical experience. The main area of work
was with outpatients (n = 113), and most of the sample worked in the private sector
(n = 77). Regarding experience, many of the professionals (n=66) saw more than 100
patients per month. Of the sample, the majority were neurologists (n=51), followed
by psychiatrists (n=50) and clinical psychologists (n=15). From the total sample,
73 (54.5%) reported having academic or research-related activities. In terms of self-reported
knowledge of FTD, the majority of professionals reported knowing “something” about
the disease (n = 81), whereas a smaller percentage reported knowing “a lot” (n = 22)
and only 1 respondent considered themselves an “expert” (n = 1).
Table 2
Demographics of the sample.
|
Characteristics
|
Total (n=100)
|
|
Age (years)
|
Mean (SD)
|
42.9 (12.5)
|
|
Sex
|
Female
|
78%
|
|
Education level
|
Ph.D., Master or Fellowship
|
41 (30.59%)
|
|
Residency (complete)
|
39 (29.10%)
|
|
Residency (undergoing)
|
10 (7.46%)
|
|
University degree
|
44 (32.83%)
|
|
Professional discipline/specialty
|
Clinical psychologist
|
15 (11.19%)
|
|
Neurologist
|
51 (38.05%)
|
|
Neuropsychologist
|
10 (7.46%)
|
|
Psychiatry
|
50 (37.31%)
|
|
Other
|
8 (5.97%)
|
|
Years of experience in healthcare
|
0-4 years
|
31 (23.13%)
|
|
5-10 years
|
40 (29.85%)
|
|
>10 years
|
63 (47.01%)
|
|
Academical/research activity
|
Yes
|
73 (54.47%)
|
|
Health system
|
Private
|
77 (57.46%)
|
|
Practice setting
|
Outpatient clinic
|
113 (84.32%)
|
|
Inpatient clinic
|
5 (3.73%)
|
|
Emergency service
|
7 (5.22%)
|
|
Chronic inpatient institution
|
9 (6.71%)
|
|
Patients seen per month
|
1-99
|
68 (50.74%)
|
|
100-199
|
47 (35.07%)
|
|
More than 200
|
19 (14.17%)
|
|
Perceived knowledge of FTD
|
None
|
3 (2.23%)
|
|
A little
|
27 (20.14%)
|
|
Moderate
|
81 (60.44%)
|
|
A lot
|
22 (16.41%)
|
|
Expert
|
1 (0.74%)
|
|
Experience in dementia
|
No experience
|
16 (11.94%)
|
|
Some experience
|
44 (32.83%)
|
|
Moderate experience
|
58 (43.28%)
|
|
A lot of experience
|
12 (8.95%)
|
|
Extensive experience
|
4 (2.98%)
|
|
Experience in FTD
|
No experience
|
39 (29.10%)
|
|
Some experience
|
61 (45.52%)
|
|
Moderate experience
|
30 (22.38%)
|
|
A lot of experience
|
2 (1.49%)
|
|
Extensive experience
|
2 (1.49%)
|
SD: Standard deviation; FTD: Frontotemporal dementia.
Psychometric properties of the Spanish FTDKS
The mean score for the Spanish FTDKS was 19.78 (range = 4-32, SD 6.38). [Table 1] shows the mean score per question for each item in the scale, the standard deviation
(SD), the item difficulty, the item discrimination, and internal consistency (Cronbach
α). The mean score per response ranged from 0.31 for statement 3 (“Among all people
with dementia, 5-10% of them have frontotemporal dementia”, False) to 1.66 for statement
1 (“Frontotemporal dementia is a type of Alzheimer disease”, False). The internal
consistency reliability (Cronbach α) for this sample was 0.74, 95% CI [0.67 ,0.8]),
indicating acceptable reliability.
DISCUSSION
The aim of the current study was to translate and adapt the original English version
of the FTDKS published by Wynn et al. into Spanish. The results obtained show that
the Spanish version has a good reliability and internal consistency and that it can
be a useful tool to evaluate the knowledge of health professionals in the field of
FTD.
A surprising result is the low mean accuracy score obtained for the third item (related
to the prevalence of FTD). Considering the lack of a registry of FTD cases in Argentina,
there are at least two interpretations for this. First, it is possible that the prevalence
of the disease in our country is, in fact, lower than that reported in the international
literature (from which the validity of the scale question is based). If this were
the case, the answers given by the respondents would not be incorrect. However, according
to the hypothesis that led us to start this work, it is possible that the information
on prevalence is ignored or unknown by respondents and the low mean score on that
item reflects a general lack of awareness of the disease by Argentine health professionals.
Another interesting factor is the low overall result obtained in the FTDKS by our
sample. With a mean of 19.78 (SD 6.3) and a range of 4 to 32, out of a maximum of
36 possible points, these results are significantly lower than those described in
the original article by Wynn et al. In that study, health professionals mean score
on the FTDKS was 25 (SD = 5.47, range = 10 - 36). These results reinforce the notion
that FTD is a poorly known illness among health professionals. With this instrument
validated in Spanish, we propose to study the level of knowledge of professionals
in Argentina and eventually throughout Latin America, focusing on the specialties
that are likely to deal first with these patients due to the characteristics of the
disease: neurologists, psychiatrists, clinical psychologists, and neuropsychologists.
