European Spine Journal 2015 (Jan); 24 (1): 72-79 ~ FULL TEXT
Marco Monticone, Howard Vernon, Roberto Brunati, Barbara Rocca, Simona Ferrante
Physical Medicine and Rehabilitation Unit,
Scientific Institute of Lissone (Milan),
Institute of Care and Research,
Salvatore Maugeri Foundation, IRCCS,
Via Monsignor Bernasconi 16, 20035,
Lissone, MI, Italy,
PURPOSE: To develop and validate NeckPix(©), a multi-image instrument for assessing daily activities in the context of pain-related fear, in order to allow its use in patients with chronic neck pain (NP).
METHODS: The measure was developed by means of item generation followed by reduction/selection. The psychometric testing included exploratory factor analysis; content validity by investigating clarity, specificity, appropriateness for the target population, relevance and completeness; reliability by internal consistency (Cronbach's alpha) and test-retest stability (intra-class coefficient correlation, ICC); and construct validity by comparing NeckPix with the Tampa Scale of Kinesiophobia (TSK), the Pain Catastrophising Scale (PCS), the Neck Disability Index (NDI) and a Numerical Rating Scale of pain intensity (NRS) (Pearson's correlation).
RESULTS: The measure, which includes ten images used to assess everyday activities in the context of pain-related fear, was administered to 118 subjects with chronic non-specific NP, and proved to be acceptable and feasible. Factor analysis revealed a one-factor solution (which explained 71.12 % of variance). The content of the images was considered adequate, appropriate for the target population, comprehensive, and relevant for evaluating activity-related kinesiophobia. The instrument's internal consistency was good (? = 0.954), as was its test-retest stability (ICC 0.979). Construct validity demonstrated a close correlation with the TSK (r = 0.759), and moderate correlations with the PCS (r = 0.583), the NDI (r = 0.520), and a NRS (r = 0.455).
CONCLUSION: NeckPix(©), which was successfully developed following international recommendations, proved to have a good factorial structure and satisfactory psychometric properties. Its use is recommended for research purposes.
Keywords: NeckPix, Neck pain, Validation, Outcome measures, Psychometric properties
From the FULL TEXT Article:
Chronic neck pain (NP) is not only related to physical
factors such as postural alterations, articular stiffness or
muscle weakness, but may also be influenced by beliefs
and behaviours, which are important determinants of
symptoms, disability and their perception.  It is now
recognised that kinesiophobia (i.e. fear-based movement
avoidance) plays a central role in the development and
persistence of spinal chronic pain. [2-6] According to the
fear-avoidance model, negative appraisals such as anxiety
or catastrophising lead to fear-avoidance beliefs that may
then lead to illness behaviour and poor physical performance;
this induces subjects to sacrifice other tasks, such as
everyday activities or the use of adaptive coping strategies. [2, 7] It is therefore important to use outcome measures to
help clinicians identify patients whose level of disability
may be determined by kinesiophobia to improve interventions
targeted at its management. [2, 8]
The Fear-Avoidance Beliefs questionnaire and the
Tampa Scale of Kinesiophobia (TSK) are two widely used
questionnaires for assessing fear of movement/re-injury in
subjects with musculoskeletal complaints. [9, 10] Studies
have demonstrated their good reliability and validity, and
they have been found to be associated with measures of
pain, disability, and mood disorders. [9, 11, 12] One limitation
is they do not provide information about which
specific activities of daily living (ADL’s) a patient might
fear or avoid. On the other hand, region-specific patient-related
outcomes for assessing “disability”, such as the
Neck Disability Index (NDI) , provide ratings of specific
activities, but these are present in differing formats in
the numerous NP-related instruments for assessing self-rated
disability. As such, they may not allow sufficient
information to be obtained that is directly related to the
patients’ first-hand self-perceptions of activity avoidance.
They are also limited by the number of ADL’s used for
rating in each of the instruments.
It has been suggested that the presentation of images of
ADL’s patients might find stressful or consider difficult to
perform can allow a more in-depth investigation of the
situations important to each individual patient which they
are avoiding during their everyday activities.  This is
the rationale underlying the development of the Photograph
Series of Daily Activities Scale (PHODAS) for
patients with chronic low back pain (LBP).  This
instrument, which consists of 100 photographs showing
everyday activities ranging from household chores to
physical exercise, investigates patients’ judgements of the
harmful consequences of everyday movements. It has
been found to have good psychometric properties ,
and has been used in studies of cognitive-behavioural
therapy (CBT). [16-18] Subsequently, the Pictorial Fear
of Activity Scale-Cervical (PFActS-C) was developed as a
tool for assessing fear in whiplash injuries; it consists of
77 photographs and evaluates the extent to which specific
kinds of biomechanical loads (i.e. direction of movement,
arm position, weight bearing, and extremity movement)
influence fear ratings. It has been found to have good
psychometric properties. 
However, given the importance of identifying specific
daily activities a patient might fear in the context of CBT
programmes for NP , and recognising the inappropriateness
of the PHODAS in relation to neck disorders and of
the limitations of the PFActS-C in assessing ADLs, we
developed a novel instrument suitable for patients with NP
called NeckPix. The aim of this article is to describe its
development and validation as a simple and rapid means of
assessing daily activities in the context of pain-related fear
of chronic non-specific NP.
This cross-sectional study was approved by our Institutional Review Board.
Outpatients attending our Physical Medicine and Rehabilitation
Unit were consecutively recruited between April
and December 2012. The inclusion criteria were chronic
non-specific (i.e. common) NP (lasting more than
12 weeks), an age of >18 years, and an ability to read and
speak Italian fluently. The exclusion criteria were acute
(lasting up to 4 weeks) and subacute non-specific NP
(lasting up to 12 weeks), specific causes of NP (e.g. disc
herniation, cervical stenosis, spinal deformity, fracture,
spondylolisthesis), central or peripheral neurological signs,
systemic illness, mental deficits, recent cerebrovascular
accidents or myocardial infarctions, chronic lung or renal
diseases, and previous CBT.
The subjects’ demographic and clinical characteristics
were recorded by a research assistant, and the eligible
patients gave their written informed consent.
Construct definition and purpose
NeckPix was designed to measure the beliefs of subjects
with chronic non-specific NP concerning pain-related fears
of a specific set of ADL’s in such a way that the scale score
would generalise to a measure of activity-related
Choice of measurement method
As the perception of pain-related fear requires direct
information from patients, we developed a multi-image
instrument with one global question about the construct
applied to each item.
The measure was developed by means of item generation
and reduction/selection. [21, 22] The first defines the
content of an index and ensures all the important variables
are considered for inclusion; the second eliminates redundant
or inappropriate items, and decreases their number to
a total that is feasible to administer to patients while
ensuring the scale measures the construct of interest.
The images were generated on the basis
of: (1) a review of the literature concerning spinal disabilities;
(2) input from patients and NP experts; and (3) a
review of the concepts covered by existing outcome scales.
A total of 50 images were generated at the end of this stage.
The developers first eliminated
24 images that were considered redundant or not clinically
related to the neck. The subsequent selection was made by
three expert evaluators (a physiatrist, a chiropractor, and a
physiotherapist) and two patients with chronic NP, who
rated the importance of each image on a five-point scale
ranging from “not at all important” to “extremely important”.
Their scores for each item were added together and
the ten images with the highest mean scores were selected.
The ten images were formatted to fit on a single page beneath the heading*: “The following
images have been created with the aim of understanding
how you feel about common situations
experienced during usual activities. Please rate each picture
according to this question: How much do you fear
doing this activity would hurt your neck? To rate the
picture, use a number from 0 to 10 where 0 = no fear and
10 = greatest fear”.
The images require no translation, and so the instructions
were translated into English to facilitate the widest
use of NeckPix. An Italian/English-speaking investigator
made the first translation, which was back translated by
another English-speaking investigator.
The instrument was administered to 20
patients with chronic non-specific NP with the aim of
verifying it was comprehensible, relevant and complete.  The results were assessed by the developers, who
decided that no further adjustment was required.
The total score ranges from 0 to 100, with higher scores
representing stronger fear-avoidance beliefs.
Figure 1 presents examples of pictures taken from the
NeckPix questionnaire. The full instrument is available
from the corresponding author by e-mail request.
Sample size calculation
This was based on the “rule of 10” patients per item ,
giving a final sample of 100. Subsequent investigations
described below were conducted on this sample.
An exploratory factor analysis was first made, and Cattell’s
scree test was used to determine the number of extracted
factors (eigenvalues.  Varimax rotation was used, and
the items with a factor loading of[0.40 were included in
the factor; the expected explained variance was >50%. 
This was based on the patients’ answers to specific questions
as no statistical testing could be involved. The
hypotheses were considered acceptable if the percentage
rate of expected answers was >90%. 
The degree to which each image adequately reflected the
construct to be measured (i.e. face validity)  was
evaluated by means of two questions investigating clarity
and specificity: “What do you think is happening here?”
and “Do some of the images overlap in any way?”
The appropriateness of the images for the population for
which they were developed (i.e. the target population in
terms of disease characteristics) was evaluated by means of
the question: “Do you think what is happening here may be
related to your neck problems?”
The degree to which the content adequately reflected the
construct to be measured (i.e. content validity)  was
evaluated by means of two questions investigating relevance
and completeness: “Do you think these images are
relevant to evaluate your fear of movement due to NP
during ADL?” and “Do you think these images comprehensively
reflect your fear of movement due to NP?”
Acceptability and feasibility
Acceptability refers to whether or not patients are willing
to complete the instrument.  The patients were asked
about any problems they encountered during the assessment,
and the examiners checked all the data, including
any missing or multiple responses.
Feasibility is the ease of using the scale in terms of time
to completion and scoring ; this was evaluated by
means of two questions: “Is this battery of images quick to
complete?” and “Is a 0–10 numerical rating scale easy to
The time needed to answer the questionnaire was also recorded.
This refers to whether an instrument can be effectively
applied to different populations and settings, and was
assessed by collecting information concerning the subjects’
age, gender, disease characteristics, and settings. 
Distribution and floor/ceiling effects
Mean values and standard deviations were calculated to
determine the distribution and floor/ceiling effects, which
were considered to be present when >15 % of the patients
had either the lowest or highest possible scores. 
Internal consistency and test–retest reliability
The first reflects the degree of interrelatedness of the items , which can be considered good if the value of Cronbach’s
alpha is >0.70; the second measures reliability over
time (i.e. the proportion of total variance in the measurements
which is due to true differences between patients ) by administering the same questionnaire to the same
subjects after a certain interval (in our case 7 days in order
to avoid the natural fluctuations in symptoms associated
with possible memory effects). The intra-class correlation
coefficient (ICC 2.1) was used to test the agreement of the
results, with good and excellent reliability being, respectively,
indicated by values of 0.60–0.80 and >0.80.
This is the degree to which the scores of a measurement
instrument are consistent with the hypotheses.  It was
hypothesised a priori the correlation between NeckPix
and the TSK should be positive, moderate to high and
closer than the correlation between NeckPix and the Pain
Catastrophising Scale (PCS), the NDI, and a Numerical
Rating Scale (NRS) of pain intensity. The correlations
were measured using Pearson correlations of r\0.30 =
little correlation; 0.30\r\0.60 = moderate correlation;
and r >0.60 = close correlation. 
TSK Fear-avoidance behaviours  were assessed using
the Italian 13-item version of this self-report measure with
the reversed items removed.  Each item was scored
using a four-point Likert scale ranging from 1 (strongly
disagree) to 4 (strongly agree), and the total score was
calculated by adding the scores of the individual items
PCS This 13-item self-report questionnaire assesses
catastrophising in subjects with musculoskeletal complaints.
Each item was scored using a five-point scale,
ranging from 0 (never) to 4 (always), and the total score
was calculated by adding the scores of the individual items
(range 0–52).  We used the Italian version. 
NDI This self-administered 10-item questionnaire
allows a comprehensive evaluation of self-rated disability
due to NP. Each question was scored on a six-point scale
ranging from 0 (no disability) to 5 (full disability), and
these were added together and the result multiplied by 2 to
obtain a total percentage score.  We used the Italian
NRS This was an 11-point pain intensity rating scale,
ranging from 0 (no pain at all) to 10 (the worst imaginable
The analyses were made using the Italian version of SPSS 20.0 software.
Of the 152 patients invited to participate in the study, 118
satisfied the inclusion criteria (77.6 %): 78 females
(66.1 %) and 40 males (33.9 %) with a mean age of
47.8 ± 15.9 years (range 20–78). The median duration of
NP was 15.5 months (range 4–60), and their mean body
mass index was 23.3 ± 3.7. Table 1 shows their general
The images were developed using a process of item generation
and reduction/selection. No special difficulties were
found by the developers and evaluators, and the pilot
testing confirmed the comprehensibility, relevance and
completeness of the instrument.
The exploratory factor analysis revealed a one-factor
structure on the basis of eigenvalues >1. The explained
variance was 71.12%, and the item-factor loadings using
orthogonal rotation ranged from 0.786 to 0.921.
The content of the images was considered adequate,
appropriate for the target population, and relevant for
the evaluation of activity-related kinesiophobia as the
percentage of correct answers was always >90%
Acceptability and feasibility
All the images were well accepted, and there were no
missing responses or multiple answers. Ease of use was
satisfactory as the percentage of expected answers was
always >90 % (Table 2). The questionnaire was completed
in 2.01 ± 0.78 min.
NeckPix can be used to assess adult subjects with chronic
non-specific NP of both genders in outpatient settings.
Distribution and floor/ceiling effects
Table 3 shows the distribution of NeckPix in comparison
with the other outcome measures. There were no floor/
Cronbach’s a was 0.954. Test–retest reliability was measured
in all the subjects and was excellent (ICC 0.979;
95 % CI 0.969–0.985) (Table 4).
All the a priori hypotheses were confirmed. Table 5 summarises
This study describes the development of the NeckPix, an
instrument for assessing activity-related kinesiophobia in
subjects with chronic non-specific NP. The motivation for
this was the limited number of image-based instruments for
assessing fear-avoidance based activity limitations. The
only other neck-related instrument, the PFActS-C , was
regarded as having limitations with respect to the large
number of items and their focus on mechanical loads on the
neck, rather than on ADL’s.
The results of the generation process indicate it was
successfully developed following international recommendations. [21, 22] The developers played an important
role during the item-generation phase, and the evaluators
and patients played a key role during the item selection/
reduction phase, which improved the content and format of
the instrument. Pilot testing on a sample of chronic nonspecific
NP subjects confirmed the generated images
created an innovative measure of activity-related
The use of factor analysis revealed the instrument’s onedimensional
structure, which suggests the strong measuring
invariance of the images. 
The content validity, acceptability and feasibility of the
instrument were satisfactory. It is self-administered and
seemed to be easy to apply for adult subjects with chronic
NP of both genders in everyday clinical practice.
The absence of any serious floor/ceiling effects demonstrated
the instrument’s ability to assess different
degrees of kinesiophobia.
Its internal consistency suggests a high degree of interrelatedness
among the items, and its excellent test–retest
reliability indicates it is a stable instrument over time. The
satisfactory internal consistency and test–retest reliability
of the PHODAS and the PFActS-C [15, 19] confirms the
reliability of such instruments.
Construct validity was initially analysed by comparing
NeckPix with the TSK, and the correlation suggests the
theoretical construct of the two measures is fairly similar;
this is not surprising as both scales evaluate kinesiophobia,
and indicate that the more harmful the activities are considered,
the higher the level of fear of movement. However,
the new measure can be expected to make a distinct
contribution to the analysis and treatment of kinesiophobia,
because it has the advantage of presenting non-verbal
material in the form of images and only solicits the score of
the patient’s rating of fear avoidance for each item; a
second advantage is that health providers can engage the
patient in a discussion of the reasons for their responses,
which should lead to a more effective approach to changing
beliefs. Poorer correlations were found between PFActS-C
and TSK (r = 0.372), suggesting that images presenting
ADLs related to neck disorders might provoke increased
fear reactions than pictures showing cervical mechanical
loads in a systematic way ; also, the smaller number of
items in the NeckPix has the advantage of avoiding
habituation to fear reactions that probably develops after a
larger number of items are presented.
The moderate association with PCS suggests there is a
link between catastrophising and activity-related kinesiophobia.
This is also not surprising because catastrophising
is considered a precursor of kinesiophobia and catastrophizers
can therefore also be expected to present increased
levels of fear of movement.  The moderate associations
with the NRS and NDI suggest the images may be conditioned
by the level of NP and disability: persisting levels of
pain and neck limitations can be expected to reinforce fearavoidance
behaviours and may contribute to chronic
vicious circles.  In accordance with our findings,
moderate associations were also found between PFActS-C
and PCS (r = 0.403) and NDI (r = 0.562). 
This study has a number of limitations. First of all, its
cross-sectional design means that any significant correlations
should not be confused with causal effects. Secondly,
the relationships between NeckPix and physical
tests were not considered because only self-administered
questionnaires were used. Thirdly, the study was
restricted to subjects with chronic non-specific NP and it
is uncertain whether the findings can be extended to
other chronic neck complaints, particularly whiplash
injury. Fourthly, the NeckPix specifically assesses only
activity-related fear of movement and, based on the
questionnaire findings, it should be seen as a starting
point to decide whether investigating more deeply the
construct of kinesiophobia by means of a wider cognitive-
behavioural evaluation. Finally, the instrument was
tested in Italian subjects and it is uncertain whether our
conclusions can be extended to different countries and
cultures; additional investigations are recommended to
confirm its properties.
NeckPix has a one-factor, 10-item structure, and is reliable and valid. It can be recommended for clinical and research purposes because it should improve the assessment of chronic NP.
The authors would like to thank Kevin Smart for his help in preparing the English version of this manuscript. The Institutional Review Board approved the research and the experimentation was conducted in conformity with ethical and humane principles of research.
Conflict of interest
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