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R E S E A R C H Open Access
The Sensory Perception Quotient (SPQ):
development and validation of a new sensory
questionnaire for adults with and without autism
Teresa Tavassoli
1,2*
, Rosa A Hoekstra
1,3
and Simon Baron-Cohen
1,4
Abstract
Background: Questionnaire-based studies suggest atypical sensory perception in over 90% of individuals with
autism spectrum conditions (ASC). Sensory questionnaire-based studies in ASC mainly record parental reports of
their child’s sensory experience; less is known about sensory reactivity in adults with ASC. Given the DSM-5 criteria
for ASC now include sensory reactivity, there is a need for an adult questionnaire investigating basic sensory
functioning. We aimed to develop and validate the Sensory Perception Quotient (SPQ), which assesses basic sensory
hyper- and hyposensitivity across all five modalities.
Methods: A total of 359 adults with (n = 196) and without (n = 163) ASC were asked to fill in the SPQ, the Sensory
Over-Responsivity Inventory (SensOR) and the Autism-Spectrum Quotient (AQ) online.
Results: Adults with ASC reported more sensory hypersensitivity on the SPQ compared to controls (P< .001). SPQ
scores were correlated with AQ scores both across groups (r = .-38) and within the ASC (r = -.18) and control groups
(r = -.15). Principal component analyses conducted separately in both groups indicated that one factor comprising
35 items consistently assesses sensory hypersensitivity. The SPQ showed high internal consistency for both the total
SPQ (Cronbach’s alpha = .92) and the reduced 35-item version (alpha = .93). The SPQ was significantly correlated
with the SensOR across groups (r = -.46) and within the ASC (r = -.49) and control group (r = -.21).
Conclusions: The SPQ shows good internal consistency and concurrent validity and differentiates between adults
with and without ASC. Adults with ASC report more sensitivity to sensory stimuli on the SPQ. Finally, greater
sensory sensitivity is associated with more autistic traits. The SPQ provides a new tool to measure individual
differences on this dimension.
Keywords: autism spectrum conditions, sensory questionnaire, sensory perception quotient
Background
In addition to the classic diagnostic criteria (social and
communication difficulties alongside unusually narrow
interests and repetitive behaviour) [1] atypical sensory
reactivity is now also recognized as being at the core of
autism spectrum conditions (ASC) [2,3]. Under Symp-
tom B the new autism criteria for DSM-5 include
‘Hyper- or hyporeactivity to sensory input or unusual in-
terests in sensory aspects of the environment (for
example, apparent indifference to pain/temperature, ad-
verse response to specific sounds or textures, excessive
smelling or touching of objects, visual fascination with
lights or movement.’[4]. The study of atypical sensory
reactivity in individuals with autism is important given
how common this is in ASC. Questionnaires are widely
used to study sensory reactivity issues in children with
and without ASC [5], in Sensory Processing Disorder [6]
and other conditions [7]. Sensory questionnaire studies
in ASC mainly record parental reports of their child’s
sensory experience [5,8-16]. Although parent reports are
an important tool, self-report is also crucial, as sensory
experiences are by definition subjective. Only a few
questionnaire studies have investigated sensory reactivity
issues in adults with ASC [17,18].
* Correspondence: teresa.tavassoli@mssm.edu
1
Department of Psychiatry, Autism Research Centre, Cambridge University,
18b Trumpington Road, Cambridge CB2 8AH, UK
2
Seaver Autism Center, Icahn School of Medicine, 1428 Madison Avenue,
10129 New York, USA
Full list of author information is available at the end of the article
© 2014 Tavassoli et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain
Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article,
unless otherwise stated.
Tavassoli et al. Molecular Autism 2014, 5:29
http://www.molecularautism.com/content/5/1/29
The most widely used measure for adults with ASC is
the Adolescent/Adult Sensory Profile (AASP), a 60-item
self-report measure that finds differences in sensory pro-
cessing in more than 90% of adults with ASC [17,19].
There have been several studies using the AASP in ASC;
one of them found that older individuals with ASC are
more similar to control groups than are younger individ-
uals [20]. In addition, adults with schizophrenia and bi-
polar disorder also show differences on the AASP
compared to controls [21]. The AASP is a useful tool be-
cause it can be used in clinical settings and describes the
particular sensory problems of an individual by assessing
specific sensory types, such as sensory sensation seeking.
However, items on the AASP include questions about
other factors that may influence our sensory experiences.
For example, there are items about visual attention (for
example, ‘I miss the street, building, or room signs when
trying to go somewhere new’), and affective reactions to-
wards sensory stimuli (for example, ‘I become frustrated
when trying to find something in a crowded drawer’). As
such, the AASP, while producing clear group differences,
measures a broader set of perceptual processes and
affective responses and not basic sensory function. Thus,
there is a need for a more fine-grained questionnaire to
dissect each perceptual process with greater precision.
More recently the Sensory Over-responsivity Scale
(SensOR) was developed to assess sensory processing dis-
order (SPD), or more narrowly sensory over-responsivity
[6]. Sensory Over-Responsivity (SOR) is defined as an ex-
aggerated response to one or more types of sensory stim-
uli [6]. The SensOR measures SOR by asking how many
sensations are experienced as aversive (for example, labels
in clothes). The SensOR was developed in combination
with an examiner-administered assessment of response to
real-world stimuli; these two measures correlate moder-
ately (r = .47) [6]. This association suggests that the Sen-
sOR is a valid and reliable tool to investigate sensory
issues. However, like the Sensory Profile, items on the Sen-
sOR include affective reactions towards sensory stimuli
(for example, participants have to rate which items in the
environment bother them), so again, it is not measuring
basic sensory sensitivity.
There is thus a need for a basic sensory perception
questionnaire that does not assess social and affective
aspects. In contrast to the SensOR and the Adult Sen-
sory Profile, the Sensory Perception Quotient (SPQ), re-
ported here for the first time, only investigates basic
sensory sensitivity, with no reference to affective re-
sponse (see Table 1). The SPQ was developed to quantify
individual differences in sensory perception in the gen-
eral population and adults with ASC, based on the as-
sumption that this trait shows variance following a
normal distribution in community samples. All five of
the main sensory modalities (vision, hearing, touch,
smell and taste) were included.
The purpose behind development of the SPQ is to as-
sist researchers studying sensory perception in adults.
Additionally, the SPQ is intended to be useful for occu-
pational therapists and other clinicians. In summary, the
objectives of the current study were: (1) to explore the
factor structure of the new SPQ, its reliability and its
concurrent validity with a previously validated instru-
ment; (2) to investigate if adults with and without ASC
show differences on the SPQ; and (3) to explore if sen-
sory sensitivity is correlated with autistic traits, both
across and within groups.
Methods
The Cambridge University Psychology Research Ethics
Committee approved the study.
Participants
Adults with ASC were recruited via an online volunteer
database hosted by the Autism Research Centre, Univer-
sity of Cambridge. These volunteers were invited to take
part in the online questionnaire study via the website at
www.autismresearchcentre.com. Data from participants
with no ASC diagnosis were collected via a parallel web-
site at www.cambridgepsychology.com. Only participants
who reported to have no psychiatric history were in-
cluded in the control group.
All participants first filled in background information
including age, sex, and history of psychiatric conditions
including when, where and by whom they were diag-
nosed. Only participants with an ASC diagnosis made by
a qualified professional (psychologist or psychiatrist)
were included in the ASC group. To validate diagnoses
in the ASC group and to screen control participants, we
Table 1 Examples of differences between the adult sensory profile (ASP), the sensory over-responsivity scale (SensOR)
and the sensory perception quotient (SPQ)
SPQ Item ASP item SensOR item Difference
I would be able to tell when an elevator/lift
started moving.
I avoid escalators and/or
elevators because I
dislike the movement.
These aspects related to
movement bother me -
going up or down escalators
SPQ items aim to measure basic
perception (for example, detection).
AASP and SensOR items also
include behavioural and affective
responses towards sensations.
If I look at a pile of blue sweaters in a shop
that are meant to be identical, I would be
able to see differences between them.
I like to go to places
that have bright lights
and that are colourful.
These visual sensations bother me: -
brightly coloured or patterned materials
(for example, clothes, drapes, wallpaper)
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used the Autism Spectrum Quotient (AQ) [22]. We used
a standard inclusion criterion of an AQ cut-off score of
26 and above for the ASC group, and a score below 26
for the control group [22,23]. Nine participants with
ASC and 43 control participants were excluded on the
basis of the AQ cut-off score, leaving 359 participants: n
= 196 participants with ASC (100 males, 96 females) and
n = 163 control participants (49 males, 114 females). Par-
ticipants were not reimbursed for taking part in the
current study.
Autism Spectrum Quotient
All participants completed the adult version of the AQ.
The AQ is a short, 50-item questionnaire measuring aut-
istic traits, with five subscales (social skills, attention
switching, attention to detail, imagination and commu-
nication) [22,23]. A score of 0 is assigned to the re-
sponses ‘definitely agree’and ‘slightly agree’and a score
of 1 for ‘slightly disagree’and ‘definitely disagree’for half
the items, and the reverse for the other half, designed to
avoid a response bias. Total scores could therefore range
from 0 to 50, with higher scores indicating more autistic
traits. Results from the AQ have been replicated cross
culturally [24,25] and across different ages [26]. The AQ
shows also good test-retest reliability [22-24].
Raven’s Progressive Matrices Test
IQ was estimated using a short online adaptation of the
Raven’s Progressive Matrices (60 items) as a timed per-
formance task [27]. The Raven’s Progressive Matrices
Test has the advantage of being language-free and it can
be used for a wide range of ages and cross-culturally
(Raven, 2000). Each item consisted of a pattern consist-
ing of a missing section, and the participant is asked to
select the option that accurately completes the pattern
shown (with 15 seconds allowed for each item).
Sensory over-responsivity scale
The SensOR Scale consists of a self-report inventory
that measures over-responsivity in several sensory do-
mains (touch, vision, hearing, smell, taste, and proprio-
ception) [6]. Participants indicated which items in their
daily environment bother them (for example, in the tact-
ile domain: labels in clothing,or in the auditory domain:
a clock ticking). The SensOR went through item analysis
and reduction prior to item selection for this edition.
The current SensOR edition consists of 76 items (28
tactile items, 20 auditory items, 9 taste items, 9 move-
ment items, 5 vision and 5 smell items). The internal
consistency reliability for the total test is high (r = .97)
and concurrent validity of the SensOR score with the
Sensory Profile score for sensory reactivity and sensory
avoiding is moderate (r = .50) [6].
Sensory Perception Quotient (SPQ): Instrument
development
We first generated items for vision, hearing, touch, smell
and taste. Next, these items were given to experts in
ASC and participants with and without ASC for feed-
back on wording and applicability. Words with affective
aspects (such as like/dislike) were avoided. Instead we
focused on basic detection and/or discrimination abil-
ities (for example, ‘I would be able to detect if a straw-
berry was ripe or not by smell alone’). In addition we
checked that where possible, items were worded appro-
priately given that adults with ASC prefer very specific,
clear, unambiguous wording (for example, ‘I would no-
tice if someone added 5 grains of salt to my water’). Half
the items were worded to identify hypersensitive (that is,
low thresholds) and half were worded to identify hypo-
sensitive items (that is, high thresholds), to avoid bias
(see Table 2 for a complete item breakdown). When
scoring, hyposensitive items were reversed, so that a low
total SPQ score indicates more reactivity.
The final version of the SPQ covered items for vision,
hearing, touch, smell and taste. We aimed to investigate
basic sensory processing and therefore included main re-
ceptors for each modality and/or the characteristics of
the environment relevant to each sense (see Table 2).
We developed questions about receptors from different
modalities and corresponding environmental stimuli (for
example, Pacinian corpuscles are tactile receptors, which
are sensitive to vibrations). The only exception was ol-
faction since there are too many receptors to develop
items for each one [28]. Instead, the main functions of
olfaction were included. Equal weightings were assigned
to vision, hearing and touch, on the basis that none of
the senses is more important than others. However we
included slightly fewer items for taste and smell since
humans do not tend to depend on chemical senses as
much as other animals [28]. Humans are microsmatic,
having a poor sense of smell, whereas many animals are
macrosmatic, having a good sense of smell [28]. Finally,
we included a larger number of items in total, so as to
be able to reduce these after an item analysis.
Table 2 Categories and subcategories of the sensory
perception quotient (SPQ)
Main categories
Touch Hearing Vision Smell Taste
(20)
a
(20) (20) (16) (16)
Subcategories
Pressure (5) Amplitude (5) Acuity (5) Social (4) Salty (4)
Temperature (5) Frequency (5) Brightness (5) Danger (4) Sweet (4)
Pain (5) Vestibular (5) Colour (5) Food (4) Sour (4)
Vibration (5) Complexity (5) Motion (5) Neutral (4) Bitter (4)
a
In brackets is the number of items per category.
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Scoring
Participants were asked to indicate to what extent they
agreed or disagreed with each statement on a Likert
scale (0 = strongly agree, 1 = agree, 2 = disagree, and 3 =
strongly disagree). All item responses were summed
[29], with a lower score indicating higher sensory sensi-
tivity. Advantages of this scale are that it avoids uncer-
tain answers, and it can be used for multidimensional
constructs.
Procedure
Participants could complete the Raven’s Progressive
Matrices, AQ, SensOR and SPQ tasks online in their
preferred order, and were allowed to log out between
tests.
Results
Descriptive statistics
PASW Statistics 18 was used to analyse the data. Tests
of normality (Kolmogorov-Smirnov test; KS) showed
that that SPQ scores were normally distributed (P> .20).
There was no significant difference between the groups
on age or IQ (P> .05). However as expected, the ASC
group had a higher mean AQ score than the control
group (t = 42.95, P< .0001) (see Table 3).
Principal component analysis
To investigate the underlying factor structure of the
SPQ a principal component analysis (PCA) was con-
ducted, using the Varimax rotation method. The PCA
was first run for the data from the control participants,
and subsequently repeated in the ASC group. Extraction
of underlying dimensions was based on inspection of the
scree plots, which suggested that the SPQ is composed
of two underlying dimensions in both the control group
and the ASC group.
Next, factor loadings were visually inspected. For the
control group, most items (38 in total) loaded on Factor
1, whilst only a few items loaded on Factor 2. Items were
retained if they showed a high factor loading (≥.35) on
the one factor and a low loading (≤.35) on the other. We
excluded ambiguous items that showed high loadings ≥
.35 on both factors [30]. A separate PCA for the ASC
group showed similar results. In this group, 43 items
loaded highly on Factor 1. In addition, 35 items that
loaded on Factor 1 in the control group also loaded on
Factor 1 in the ASC group (see Table 4). For Factor 2,
the loadings across both groups were low and inconsist-
ent. These results suggest that one factor, encompassing
35 items, consistently assesses sensory reactivity traits in
both adults with ASC and controls.
Item distribution analysis
In addition, an item distribution analysis was conducted.
Items on which more than 70% of the participants gave
the same response were excluded, since items with very
little variance are not informative [31]. Four such items
were identified: item, 8, 16, 47 and 54. On these items
most participants ‘strongly agreed’(scoring 0). None of
these items loaded on Factor 1.
Item reduction
In sum, the PCAs suggest that one factor including 35
items consistently assesses traits related to sensory re-
activity in both a control group and a clinical group (see
Table 4). All these 35 items show considerable response
variation. Out of the 35 items loading onto Factor 1, 10
items assessed reactivity to touch, 10 items assessed
smell, 6 vision, 5 hearing, and 4 taste. Most of the items
(31 out of 35) were hypersensitive items.
Reliability
For all 92 items, the split-half reliability was high (Spearman-
Brown = .91, P< .0001). Additionally, Cronbach’salpha
suggested excellent internal consistency for both the full 92
item version of the SPQ (α= .92) and for the reduced
35-item version (α= .93).
Concurrent validity
To test the concurrent validity of the SPQ the associ-
ation with the SensOR was examined. High scores on
the SensOR and low scores on the SPQ represent more
reactivity to stimuli in the environment. The total SPQ
and SensOR correlated moderately (r = -.50, P< .0001)
both across groups and within the ASC (r = -.49, P
= .007) and control group (r = -.23, P= .004) (see Fig-
ure 1). The concurrent validity was lower for the item
reduced version of the SPQ (r = -.20, P= .0001).
Differences between the groups
A MANOVA with group and sex as fixed factors showed
that groups differed significantly on the SPQ total scores
(F(6,339) = 13.44, P< .0001) (see Table 5). Post hoc tests
showed that groups differed significantly on the total
SPQ, the item-reduced version, and for all subscales
other than smell. Additionally, sex differences were
found for the total SPQ (F (1) = 4.71, P< .005), and for
smell and taste reactivity; females in both groups had
Table 3 Descriptive characteristics of the Autism
Spectrum Condition (ASC) and control groups
ASC
group
Control
group
Group
difference
N 196 163 -
Age in years (SD) 38.7 (12.7) 36.8 (12.3) No, P> .05
AQ score (range from 0 to 50) 40.4 (5.1) 15.4 (6.2) Yes, P< .0001
Raven score (range from 0 to 60) 50.3 (10.5) 51.5 (7.4) No, P> .05
AQ, Autism Spectrum Quotient.
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Table 4 Item loadings for factors 1 (Fac1) and 2 (Fac2) for all 92 items of the Sensory Perception Quotient (SPQ), and
item breakdown of the SPQ domains and subdomains (for example, taste-salty)
Factor loadings and item break down Factor loading Item domain
Item Control
group
ASC
group
Fac1 Fac2 Fac1 Fac2
1 I would notice if someone added 5 grains of salt to my cup of water. .34 -.18 .38 -.35 Taste-salty
2
a
I would be able to distinguish different people by their smell. .60 .23 .42 -.22 Smell-social
3 I wouldn’t notice if someone added a spoonful of sugar to my tea. .02 .15 .35 .40 Taste-sweet
4 I wouldn’t be afraid of hurting myself when falling off my bike at high speed. .04 -.01 .03 .52 Touch-pain
5 I wouldn’t be able to detect the motion of the blades of a rotating fan even when
it is at minimum speed.
.09 .36 .30 .48 Vision-motion
6 The sound of a piano and a violin playing the same note seems very similar to me. -.02 .22 .26 .39 Hearing-complexity
7
a
I would be able to detect if a strawberry was ripe by smell alone. .38 .25 .55 -.11 Smell-food
8 I would be able to distinguish milk chocolate and dark chocolate by their taste alone. .31 .33 .47 .09 Taste-sweet
9 I cannot tolerate hot showers (above 40°C /105°F). .16 -.28 .23 -.12 Touch-pain
10 I wouldn’t need an anaesthetic to cope with a dental procedure, such as a cavity-filling. -.02 -.03 .13 .39 Touch-pain
11 I would have to wait for 10 minutes for a hot drink to cool down before swallowing it,
otherwise it would be too hot for me.
.27 -.19 .26 -.16 Touch-temperature
12
a
I would be able to visually detect the change in brightness of a light each time a dimmer
control moved one notch.
.49 .04 .60 -.23 Vision-brightness
13 I wouldn’t be able to detect large objects, such as parked cars, clearly on a dark night. -.12 .46 .33 .42 Vision-brightness
14
a
I would notice if someone added 5 drops of lemon juice to my cup of water. .48 .13 .56 -.08 Taste-sour
15 I would be the last person to detect if something was burning. .43 .30 .58 .46 Smell-danger
16 I wouldn’t be able to feel the vibrations from loud music if I was sitting next to the loud
speaker (for example, at a concert).
.04 .19 .38 .65 Touch-vibration
17 I wouldn’t be able to feel a small volume change in music as a difference in vibration
on my skin.
-.30 .19 -.63 .02 Touch-vibration
18 I can’t hear the TV when it is quiet, even when other people can. .01 .41 .33 .21 Hearing-loudness
19
a
I would be able to hear a leaf move if blown by the wind on a quiet street. .43 .05 .59 -.20 Hearing-loudness
20 I wouldn’t be able to taste the difference between two pieces of dark chocolate. .34 .18 .60 .10 Taste-sweet
21
a
I would be able to taste the difference between two brands of salty potato chips/crisps. .48 .17 .60 -.11 Taste-salty
22 When people are talking the words seem to merge together. -.32 .60 -.08 .42 Hearing-complexity
23 I can only look at bright colours for a brief period of time. .34 -.61 .48 -.47 Vision-colour
24 I would lose my balance very easily if I was standing on one foot with my eyes closed. .25 -.51 .03 -.41 Hearing-vestibular
25 I wouldn’t be able to smell a barbecue from 60 feet (20 metres) away. .40 .27 .52 .41 Smell-food
26 I can’t spin round and round without falling over. -.17 .42 -.24 .33 Hearing-vestibular
27 I wouldn’t notice a 10 degree difference in temperature of the weather. .22 .36 .24 .57 Touch-temperature
28 I can drink tea/coffee ‘straight’, without needing to add milk or sugar. .20 -.26 .23 .06 Taste-bitter
29 I can’t hear the bass in music. .30 .35 .45 .42 Hearing-frequency
30 I would be able to smell the difference between freshly cut grass and uncut grass. .27 .14 .49 -.05 Smell-neutral
31
a
I wouldn’t be able to feel the label at the back of my shirt even if I thought about it. .50 -.29 .57 .21 Touch-pressure
32
a
I can hear electricity humming in the walls. .43 -.36 .57 .44 Hearing-frequency
33
a
I notice the flickering of a desktop computer even when it is working properly. .52 -.32 .61 -.46 Vision-motion
34 I wouldn’t be able to tell if milk is off simply by smelling it. .22 .41 .52 .38 Smell-food
35
a
I would be able to notice a tiny change (for example, 1 degree) in the
temperature of the weather.
.46 .09 .58 -.32 Touch-temperature
36
a
I would be able to feel a one millimetre cut in my skin. .36 .09 .44 -.13 Touch-pain
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Table 4 Item loadings for factors 1 (Fac1) and 2 (Fac2) for all 92 items of the Sensory Perception Quotient (SPQ), and
item breakdown of the SPQ domains and subdomains (for example, taste-salty) (Continued)
37 I would be able to see the individual blades in a rotating fan even if it was
at maximum speed.
.29 -.20 .26 -.44 Vision-motion
38
a
I would be able to tell the weight difference between two different coin
sizes on the palm of my hand, if my eyes were closed.
.42 .03 .62 -.25 Touch-pressure
39 I wouldn’t get dizzy on a carousel/merry-go-round, even at high speed. .03 .07 -.02 .24 Hearing-vestibular
40 I can’t see written words on a page that other people can see. -.12 .37 -.14 .63 Vision-acuity
41 I would be able to distinguish between two oranges purely by their taste. .48 .22 .31 -.11 Taste-sour
42
a
I couldn’t distinguish a familiar person and a stranger by their smell. .41 .25 .42 .11 Smell-social
43
a
I couldn’t detect if bread is stale purely by its smell. .38 .06 .58 .16 Smell-food
44 I can’t tell if my clothes are clean or dirty by smell alone. .30 .35 .43 .48 Smell-neutral
45
a
I would be able to detect the sound of a vacuum cleaner from any room in a
two-storey building.
.44 .04 .51 -.03 Hearing-frequency
46 I wouldn’t notice the difference between even and uneven ground when driving
over it sitting in the back seat of a car.
.38 .31 .46 .47 Touch-vibration
47 I would be able to drink a cup of boiling water straight after it had been poured
from the kettle.
-.03 .04 .16 .49 Touch-pain
48 I couldn’t tell two types of green apples apart purely from their colour. .31 .26 .49 .36 Vision-colour
49 I would be able to distinguish between an old and a new book by their smell. .25 .18 .58 -.06 Smell-neutral
50 I would be able to read a street sign from a distance of 100 feet (30 metres). -.09 .29 .22 -.01 Vision-acuity
51 I can’t tell if cars passing me on the street are going at different speeds. .15 .35 .25 .51 Vision-motion
52 I would be able to notice if someone added 5 grains of sugar to my glass of water. .37 -.05 .35 -.30 Taste-sweet
53 I would have difficulty seeing a single leaf clearly even on a tree that is close up. .21 .36 .34 .56 Vision-acuitity
54 I wouldn’t taste if someone added a whole teaspoon of salt to my glass of water. .20 .37 .23 .56 Taste-salty
55
a
I would be able to feel the elastic holding up my socks if I stop and thought about it. .57 -.11 .57 -.11 Touch-pressure
56 I can’t taste the difference between ripe and non-ripe fruit. .21 .41 .39 .56 Taste-sweet
57 I would be able to stand on one foot for fifteen seconds without wobbling. .15 -.44 .22 -.06 Hearing-vestibular
58
a
I would be able to taste the difference between apparently identical pieces of candy. .37 -.27 .59 -.27 Taste-sweet
59
a
I notice the weight and pressure of a hat on my head. .49 -.06 .61 -.19 Touch-pressure
60
a
I would feel if a single hair touched the back of my hand. .59 -.08 .64 -.20 Touch-pressure
61
a
If I was walking along, I would be able to feel a passing truck’s vibrations even if
my eyes were closed.
.54 -.00 .69 -.07 Touch-vibration
62
a
I would be able to smell the smallest gas leak from anywhere in the house. .64 -.09 .71 -.29 Smell-danger
63
a
I wouldn’t notice if someone changed their perfume, by smell alone. .43 .19 .59 .23 Smell-social
64 I would be able to tell when an elevator/lift started moving. .25 .07 .53 .10 Hearing-vestibular
65 I can hear dog whistles very easily in the park. .32 -.15 .50 -.30 Hearing-frequency
66 I wouldn’t taste the difference between different types of lettuce leaves. .45 .27 .17 .36 Taste-bitter
67 I couldn’t taste if there were two slices of lemon in my glass of water if I was
drinking it with my eyes closed.
.31 .19 .48 .51 Taste-sour
68
a
I can’t go out in bright sunlight without sunglasses. .47 -.26 .55 -.35 Vision-brightness
69 I would be able to read small print, such as a serial number on the back of a DVD,
at 10 feet (3 metres) away.
-.17 .02 .04 -.38 Vision-acuity
70 I get motion sickness easily (for example, car sickness or sea sickness) .21 -.01 -.01 -.11 Vision-motion
71
a
I would be able to feel a change in the temperature of a cup of coffee after it had
sat for 1 minute.
.51 .07 .56 -.12 Touch-temperature
72 I can’t hear very low frequency sounds, such as low voices. .09 .52 .44 .27 Hearing-frequency
73
a
I would be the first to hear if there was a fly in the room. .61 -.08 .70 -.27 Hearing-loudness
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lower scores on the SPQ (more sensitive) (see Table 5).
Gender had however no effect on SPQ-short scores. Re-
sults from the SenSOR are reported elsewhere [32].
Correlation between Sensory Perception Quotient and
autistic traits
The total SPQ was correlated with the AQ across groups
(r = -.38, P= .0001) and within the ASC group (r = -.18,
P= .009), and marginally within the control group
(r = -.15, P= .06). A higher score on the AQ corresponds
with more autistic traits, while lower scores on the SPQ
suggest a lower sensory threshold and thus a higher sen-
sory sensitivity. The reduced SPQ also correlated with
the AQ (r = -.14, P= .007). There was no correlation be-
tween SPQ total scores and age (P= .58) or IQ (P= .95).
Discussion
The current study reports the development and valid-
ation of the Sensory Perception Quotient (SPQ), a new
sensory questionnaire that provides a quantitative meas-
urement of individual differences in basic sensory per-
ception. The SPQ shows excellent internal consistency
and good validity. Adults with ASC reported being more
sensitive than control participants to sensory stimuli in
vision, hearing, touch and taste, but not smell. Reliable
sensory sensitivity measures for adults with ASC are
needed since sensory symptoms are now recognized as
being at the core of ASC. Past questionnaire-based stud-
ies already highlighted the importance of sensory re-
activity in ASC, but often used parent reports [5,8-16].
Since it is easier to judge your own sensory experiences
the SPQ is an important new self-report questionnaire.
This new questionnaire also adds to a battery of new di-
mensional measures (the Autism Spectrum Quotient
(AQ), the Empathy Quotient (EQ) and the Systemizing
Quotient (SQ)) that seek to provide a metric of the
spectrum on which ASC lies, and the relationship be-
tween ASC and variation in the general population
[22,33,34].
With regards to item analysis, principal component
analyses suggest that one factor including 35 items con-
sistently assesses traits related to sensory sensitivity, in
both the clinical group and the control group. Both the
short 35-item version and the total 92-item version of
Table 4 Item loadings for factors 1 (Fac1) and 2 (Fac2) for all 92 items of the Sensory Perception Quotient (SPQ), and
item breakdown of the SPQ domains and subdomains (for example, taste-salty) (Continued)
74
a
If I look at a pile of blue sweaters in a shop that are meant to be identical, I would
be able to see differences between them.
.51 -.26 .68 -.25 Vision-colour
75
a
I wouldn’t detect a new smell in my house instantly before anyone else. .55 .26 .58 .19 Smell-neutral
76 I have perfect pitch: for example, I could repeat a musical tone without any cue. -.42 .04 -.21 .16 Hearing-complex
77 I would be able to bite into a lemon without any problems. .15 -.32 .18 .25 Taste-sour
78 I wouldn’t need to wear a coat in the winter, even when it is zero degrees outside. -.01 -.03 -.12 -.52 Touch-temperature
79 I wouldn’t be able to match the colour of a sweater in the shop with the colour of
my trousers at home.
.22 .07 .14 .34 Vision-colour
80 I wouldn’t hear every single note when listening to music. .39 -.01 .33 .21 Hearing-frequency
81
a
I would be able to smell the difference between most men and women. .51 .25 .59 -.19 Smell-social
82 I choose to wear muted colours. .14 -.33 .41 -.31 Vision-brightness
83 I listen to music at minimum loudness. .15 -.22 .31 -.27 Hearing-loudness
84
a
I would be able to hear each note in a chord even if there were 10 notes. .38 -.13 .43 -.25 Hearing-complexity
85
a
I close curtains to avoid bright lights. .46 -.45 .49 -.37 Vision-acuity
86 I wouldn’t be able to hear differences in sound if the same instrument played the
same note at different times.
.27 -.12 .50 .20 Hearing-complex
87
a
I would be able to distinguish two brands of coffee by their smell, even with my
eyes closed.
.50 .01 .66 -.16 Smell-food
88
a
I can see dust particles in the air in most environments. .50 -.37 .63 -.42 Vision-acuity
89
a
I wouldn’t be able to taste the difference between two brands of tomato sauce if
they had different concentrations of salt.
.43 .26 .60 .35 Taste-salty
90
a
I would be able to smell the smallest amount of burning from anywhere in the house. .62 -.10 .76 -.20 Smell-danger
91
a
If my mobile phone was vibrating in my pocket I would be quick to sense it. .43 -.01 .59 .12 Touch-vibration
92 I find it difficult to see individual stars on a clear night. .15 .21 .43 .47 Vision-acuitity
Sensory domains included: vision, hearing, touch, smell and taste. Italic items are linked to high thresholds (hyposensitive). Non-italic items are linked to lower
thresholds (hypersensitive).
a
Items included in the short version of the SPQ (those items with factor load ings >.35 in one factor for both groups and a low loading (≤.35) on the other factor).
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the SPQ showed high internal consistency. In addition
the SPQ correlated with the AQ, meaning greater sen-
sory reactivity is associated with more autistic traits. Fur-
thermore the SPQ was moderately correlated to a
validated sensory scale, the SensOR. It is not surprising
that the SPQ and SensOR are not perfectly related, as the
SensOR also assesses the affective response to sensory
stimuli, whilst the SPQ focuses on basic sensory percep-
tion only. Future studies need to test whether SPQ scores
correlate to laboratory-measured reactivity measures. In
addition, future studies are needed to investigate other test
characteristics, such as test-retest reliability.
A limitation of this study is the uneven sex ratio be-
tween the groups (more females in the control group).
However the ASC and control group differed on the SPQ
even when sex was included as a factor. Sex had an effect
on the full SPQ, in line with findings from the Sensory
Profile [35]. Females in both groups have lower scores on
the SPQ, meaning women report being more sensitive.
Since females with ASC reported they were more sensi-
tive, the question arises if sensory issues affect females
with ASC to a greater extent. A recent study shows that
women with ASC report more life-time sensory issues
compared to men with ASC [36]. This is important and
needs more research since most studies neglect female
participants with ASC and mostly include males. Finally,
given that this is the first report of the SPQ, future studies
are necessary to generate a normative dataset.
Conclusions
The SPQ is a reliable and valid new tool to measure sen-
sory sensitivity in adults with and without ASC. Adults
with ASC report more sensory sensitivity than controls,
Figure 1 The correlation between the Sensory Perception Quotient
(SPQ) with the sensory over-responsivity (SensOR). The lower the
score on the SPQ the more sensitive a person is, and the higher the score
on the SensOR the more sensitive. ASC, autism spectrum conditions.
Table 5 The mean sensory perception quotient (SPQ) scores before and after item reduction and for all subscales for
vision, hearing, touch, smell and taste, for females and males with and without Autism Spectrum Condition (ASC)
Sex SPQ SPQ SPQ SPQ SPQ SPQ
Smell
SPQ
Taste
Full Short Vision Hearing Touch
ASC group Both 92.95 38.55 22.12 22.56 18.35 14.56 14.34
(±26.61) (18.68) (±6.61) (±5.41) (±6.29) (±8.34) (±6.39)
Male 97.5 40.70 22.77 23.37 23.37 15.93 15.75
(±25.24) (19.84) (±6.36) (±6.36) (±5.33) (±8.29) (±5.78)
Female 88.21 36.25 21.54 21.54 18.58 13.12 12.87
(±27.30) (±17.20) (±6.84) (±6.84) (±5.39) (±8.23) (±6.69)
Control group Both 108.96 43.01 27.12 25.85 22.74 14.85 16.25
(±20.53) (±14.67) (±5.35) (±4.79) (±5.20) (±5.85) (±5.09)
Male 110.06 43.01 27.25 25.58 22.70 16.00 17.85
(±17.53) (±14.67) (±4.16) (±4.57) (±4.46) (±6.10) (±5.50)
Female 106.84 44.57 27.09 25.95 22.74 14.34 15.53
(±21.71) (±14.60) (±5.82) (±4.93) (±5.52) (±5.69) (±4.75)
Group difference? 6.71
a
8.20
a
58.33
a
26.80
a
41.74
a
.89 16.80
a
F (p) (.01) (004) (.0001) (.0001) (.0001) (.34) (.000)
Sex difference? 8.42
a
2.41 2.85 2.18 .26 6.73
a
21.12
a
F (p) (.004) (.12) (.09) (.14) (.60) (.01) (.0001)
Standard deviations are shown in brackets. The SPQ full includes all 92 items and SPQ short includes the 35 item reduced version. In addition, group and sex
differences are presented.
a
Pvalues ≤.01
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and this may have important implications for how they
manage their everyday lives. The SPQ is a useful standard-
ized measure for basic sensory perception in adults with
ASC, other clinical disorder and neurotypical adults. Uses
of the SPQ include assisting researchers studying sensory
issues in adults (for example, in phenotyping studies), and
to assist clinicians, such as occupational therapists, in
assessing the sensory needs of people with autism.
Abbreviations
AASP: adolescent/adult sensory profile; ASC: autism spectrum conditions;
ASP: adult sensory profile; SenSOR: sensory over-responsivity scale;
KS: Kolmogorov-Smirnov test; PCA: principal component analysis;
SPQ: sensory perception quotient.
Competing interests
The authors of this paper report that they have no biomedical financial
interests or potential conflicts of interest.
Authors’contributions
TT and SBC designed the SPQ. TT collected the data and TT and RH carried
out the data analyses. All authors were involved in writing the manuscript
and approved the final version.
Acknowledgements
TT was supported by the Wallace Research Foundation and the Autism
Science Foundation. SBC was supported by the MRC UK, the Wellcome Trust,
and the Autism Research Trust. This work was conducted in association with
the NIHR CLAHRC EoE. We are grateful to the participants for their generous
cooperation, and to Dr. Carrie Allison for her help.
Author details
1
Department of Psychiatry, Autism Research Centre, Cambridge University,
18b Trumpington Road, Cambridge CB2 8AH, UK.
2
Seaver Autism Center,
Icahn School of Medicine, 1428 Madison Avenue, 10129 New York, USA.
3
Department of Life Health and Chemical Sciences, The Open University,
Milton Keynes MK7 6AA, UK.
4
Cambridgeshire and Peterborough NHS
Foundation Trust, CLASS Clinic, Cambridge CB21 5EF, UK.
Received: 18 December 2013 Accepted: 31 March 2014
Published: 24 April 2014
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Cite this article as: Tavassoli et al.:The Sensory Perception Quotient
(SPQ): development and validation of a new sensory questionnaire for
adults with and without autism. Molecular Autism 2014 5:29.
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