WAYFINDING IN DOWN SYNDROME 1

WAYFINDING BEHAVIOUR IN DOWN SYNDROME:

A STUDY WITH VIRTUAL ENVIRONMENTS.

Yannick Courbois(a), Emily Farran(b), Axelle Lemahieu(a), Mark Blades(c), Hursula

Mengue-Topio(a), Pascal Sockeel(a).

(a) PSITEC, UDL3, Université Lille Nord de France, F59653, Villeneuve d’Ascq, France

(b) Department of Psychology and Human Development, Institute of Education, London

WC1H 0AA, UK

(c) Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK

Corresponding author: Yannick Courbois

Email : Yannick.courbois@univ-lille3.fr

Phone number: +33 (0)3 20 41 63 77

Address : Laboratoire PSITEC (EA4072), UDL3, Université Lille Nord de France, F59653,

Villeneuve d’Ascq, France.

WAYFINDING IN DOWN SYNDROME 2

Courbois,  Y.,  Farran,  E.  K.,  Lemahieu,  A.,  Blades,  M.,  Mengue-­‐Topio,  H.,  &  Sockeel,  P.  

(2013).  Wayfinding  behaviour  in  Down  syndrome:  A  study  with  virtual  

environments.  Research  in  Developmental  Disabilities,  34(5),  1825-­‐1831.  doi:  

http://dx.doi.org/10.1016/j.ridd.2013.02.023  

KEYWORDS :

DOWN SYNDROME, SPATIAL ORIENTATION, WAYFINDING, VIRTUAL

ENVIRONMENT

WAYFINDING IN DOWN SYNDROME 3

ABSTRACT

The aim of this study was to assess wayfinding abilities in individuals with Down

syndrome (DS). The ability to learn routes though a virtual environment (VE) and to make a

novel shortcut between two locations was assessed in individuals with DS (N=10) and control

participants individually matched on mental age (MA) or chronological age (CA). The results

showed that most of the participants with DS were able to learn routes through the VE, even

though they needed more trials than the CA controls to reach the learning criterion. However,

they did not show flexible wayfinding behaviour because they were unable to find a shortcut

between two known locations (unlike the CA controls). The results suggest that most

individuals with DS can acquire knowledge about specific routes, but are unable to integrate

that knowledge into a configurational understanding of the environment.

WAYFINDING IN DOWN SYNDROME 4

1. Introduction

Down syndrome (DS), also referred to as Trisomy 21 (Roubertoux & Kerdelhué,

2006), has an incidence of about 1 in 650-1000 live births and it is the most common genetic

cause of intellectual disability (Bittles, Bower, Hussain, & Glasson, 2007). This genetic

syndrome has been the subject of widespread cognitive research over the past two decades,

highlighting a specific cognitive profile, characteristic of most individuals with DS. This

profile comprises relative weaknesses in language contrasting with relative strengths in

visuo-spatial tasks.

Difficulties in the language domain have been extensively studied (Naess, Lyster,

Hulme, & Melby-Lervag, 2011). Individuals with DS show deficits in expressive vocabulary,

grammar and verbal short-term memory when they are compared to typically developing

(TD) children with the same non-verbal mental age (Chapman, 1997; Jarrold, Thorn &

Stephens, 2009). In contrast, their receptive vocabulary level is comparable to their non-

verbal intellectual level (Facon, Magis & Courbois, 2012; Naess et al., 2011). Researchers

have devoted less attention to spatial processes, which have mainly been investigated through

visuo-spatial short-term memory. Convergent evidence has shown that individuals with DS

have a relatively good level of performance on the Corsi Block Task, a measure of visuo-

spatial short-term memory. In this task, nine identical blocks are irregularly positioned on a

wooden block. The experimenter points to a particular sequence of blocks at the rate of one

block per second. Then, the participant is required to recall the sequence of blocks.

Individuals with DS perform as well as TD children with the same mental age (MA) (Frenkel

& Bourdin, 2009; Jarrold & Baddeley, 1997; Visu-Petra, Benga & Miclea, 2007) and as well

as individuals with other intellectual disabilities with the same MA on the Corsi Block Task

(Numminen, Service, Ahonen & Ruoppila, 2001). These results contrast with their poor

WAYFINDING IN DOWN SYNDROME 5

performance on verbal short-term memory tasks, which is below their level of MA (Jarrold &

Baddeley, 1997). Lanfranchi, Cornoldi & Vianello (2004) also found that the relative strength

in visuo-spatial tasks disappeared when the executive control required by the task is

increased. They used a battery of five visuo-spatial tasks requiring different levels of control

and executive resources. DS participants performed lower than the MA control group only

when the visuo-spatial tasks involved a high level of executive resources (Lanfranchi,

Baddeley, Gathercole & Vianello, 2012).

The majority of experiments with individuals with DS have included small-scale

spatial tasks only. There have been very few attempts to assess visuo-spatial abilities in large-

scale spatial tasks (Pennington, Moon, Edgin, Stedron, & Nadel, 2003; Uecker, Mangan,

Obrzut, & Nadel, 1993). This is surprising since there is considerable evidence in cognitive

psychology and in neuroscience showing that processing spatial information at different

scales of space involves different processes and brain structures (Hegarty, Montello,

Richardson, Ishikawa, & Lovelace, 2006). For example Previc (1998) identified different

brain systems involved in spatial processing, including the peripersonal system and the action

extrapersonal system. The former is mainly devoted to the near-body space and is involved in

reaching and manipulative behaviours. It is predominantly located in the dorsolateral cortex.

The later is used in spatial navigation and is located in the hippocampus and

parahippocampal regions (Previc, Declerck, & de Brabander, 2005). Moreover, convergent

evidence has suggested that specific impairments in the hippocampal system are an important

part of the cognitive phenotype in DS (Nadel, 2003). Clearly, research on spatial navigation

in DS is required.

Mangan (1992) tested two groups of ambulatory pre-school children with DS (16 to

20 months and 26 to 30 months), and two groups of age-matched control children, on three

spatial tasks. A response learning task required the children to learn a specific motor response

WAYFINDING IN DOWN SYNDROME 6

to locate a hidden toy. The toy was always hidden in the same location and the child was

always placed in the same location so that they could locate the target by using a fixed motor

sequence (Uecker, et al., 1993). A cue learning task required them to learn an association

between a single cue and the location of the goal (the participants found the toy when they

approached a specific coloured cue). A place learning task required the utilisation of multiple

cues to locate the goal. Successful performance on this task needed the child to rely on a

representation of the spatial relationship between multiple cues and the toy location (a

cognitive map), a spatial ability that depends on the hippocampal formation (Mangan, 1992;

Nadel, 2003; Uecker, et al., 1993). Each task began with training trials which continued until

children had reached a learning criterion. Children then took part in a memory test; they saw

the toy being hidden, were removed from the apparatus for approximately one minute to take

part in a distraction task, and were then returned to the apparatus and asked to find the toy.

The results showed that children with DS needed more trials to reach the criterion in all three

tasks, but they managed to learn the location of the toy. On the memory tests, they performed

at the same level as CA children on the response and cue tasks but they were severely

impaired on the place task. This pattern of results is consistent with the hippocampal

dysfunction hypothesis (Mangan, 1992; Nadel, 2003; Uecker, et al., 1993).

Pennington, et al. (2003) conducted a neuropsychological assessment of prefrontal

and hippocampal functions in participants with DS (mean CA =14.7) who were compared to

MA matched TD children (mean MA = 4.9). Participants took part in a computer generated

virtual Morris water maze task, which was designed to study place learning and memory in

humans (this task was an adaptation from the water maze task used in animals to study

cognitive maps; Morris, 1981). In this task, the participants were required to find an invisible

platform located in a virtual circular arena, which was surrounded by four walls with

distinctive features. The platform remained in the same place across trials and the participants

WAYFINDING IN DOWN SYNDROME 7

had to learn its spatial location relative to the distal cues provided by the features on the

walls. The participants with DS had a lower level of performance than children with the same

MA on this task. This reflects poor generation and use of a cognitive map in DS, a function

of the hippocampus.

Thus, the existing research suggests that individuals with DS have difficulties in

coding the spatial location of an object in terms of distance and direction with respect to

landmarks located in the local surround. Such place learning difficulties may also impact

spatial navigation in more complex and ecologically valid tasks where the target destination

is located in a neighbourhood and is not visible from the current location. In large-scale

spatial tasks, space can be viewed only in segments, and information from multiple views

must be integrated (McDonald & Pellegrino, 1993). Such tasks require wayfinding, which

can be defined as a goal-directed and planned movement of one’s body around an

environment with respect to both distal and local features of the environment (Montello,

2005). Efficient wayfinding behaviour can take different forms. At a basic level, individuals

simply have to know what action to take when they reach decisions points. The order of the

decision points, together with the sequence of paths travelled from one decision point to

another constitutes a route (Hunt & Waller, 1999). At a higher level, individuals know the

configuration of the environment, and locations are defined in terms of the distance and

direction of the location to landmarks or important places. At this level, individuals’

wayfinding behaviour is flexible, because they can navigate along novel paths and create

shortcuts. A deficit in place learning in individuals with DS may impair their ability to create

a configurational representation of their environment. However, it would not impair their

ability to learn routes, provided that there are proximal landmarks along the path.

In the present experiment, we employed a VE to assess wayfinding abilities using

methodology adapted from Mengue-Topio, Courbois, Farran & Sockeel (2011), which

WAYFINDING IN DOWN SYNDROME 8

allowed us to assess memory for landmarks, route learning abilities, and shortcut

performance. There were three groups: individuals with DS and two groups of TD

individuals (a group of 22-year-olds matched to the DS individuals for CA and a group of 7-

year-olds matched to the DS individuals for MA).

Participants were shown two routes (A B) and (A C) and then were tested to

find out how well they recognised the landmarks along those routes. After participants had

been shown each route, they were asked to retrace it themselves until they had learnt the

route. The number of learning trials required to reach a learning criterion was used as an

index of route learning abilities. This study was the first to explore route learning in people

with DS. We expected the participants with DS to be able to learn the routes since place

learning deficits do not alter route learning when there are proximal landmarks along the

path. However, we also predicted that the participants with DS would need more trials than

the CA group to learn the routes. Indeed, there is evidence that individuals with intellectual

disabilities learn new routes in VE at a slower rate compared with individuals of the same CA

(Mengue-Topio et al., 2011).

After learning both routes participants were placed at B and were asked to find the

shortest way to C. Shortcut performance was an index of configurational knowledge. We

expected individuals with DS not to be able to find the shortest way since their deficit in

place learning would impair their ability to create a configurational representation of their

environment. Moreover, based on Pennington et al.’s (2003) results on a virtual Morris water

maze, we also expected individuals with DS to perform less well than the MA control group

in the shortcut task.

2. Method

2.1 Participants

Three groups of participants were assessed (N=10 per group): Individuals with DS,

WAYFINDING IN DOWN SYNDROME 9

TD individuals matched to the DS group on chronological age (CA), and TD children

matched to the DS group on MA.

All the participants, except one child in the MA group, used a computer several times

per week. Six individuals in the DS group, 7 in the CA group and 8 in the MA group, also

reported experience with computer games. The DS group comprised 6 females and 4 males,

ranging in age from 14.2 to 29.9 years (mean age: 22.22, standard deviation (sd) = 5.3). MA

was assessed with the Nouvelle Echelle Métrique de l’Intelligence, NEMI-2 (Cognet, 2006).

This is a French intelligence test comprising of 4 core subtests. The completion time for this

short intelligence test is about 30 mn. The NEMI-2 is a reliable tool that provides an IQ score

(Indice d’Efficience Cognitive, IEC) and age equivalence information for performance on

each subtest. The correlation between IEC and IQ score from the WISC-III is high (.80). The

test-retest reliability for the 4 core subtests ranges between .82 and .86 (information: .86;

similarities: .90; analogical matrix: .82; vocabulary: .88). The MA of the DS group ranged

from 7 to 9 years (mean MA = 7.68; sd = 0.99).

The CA group comprised 10 participants who were individually matched to the DS

participants on sex and age (+/- 6 months; mean age: 22.11, sd = 5.21). The MA group was

composed of 10 children individually matched to the DS participants on the basis of sex and

MA (+/- 6 months; mean age: 7.73, sd = 1.07). We did not obtain consent for IQ testing in the

MA group, but we are confident that their chronological age was a good indicator of MA in

these children. Consent for taking part in the study was obtained from the parents of the

participants in DS and MA groups (and for children under 18 in the CA group). All of the

participants were informed regarding the nature of the study and gave their consent to take

part in it. They were also informed that they were free to withdraw from the study at any

time.

2.2 Materials

WAYFINDING IN DOWN SYNDROME 10

The study was conducted in a VE using the 3D VIDIA VIRTOOLS software

(Dassault Systèmes). The VE measured 300m × 300m and comprised a 4 × 4 regular grid of

streets lined with high brick walls (see Figure 1 for a map of the VE). This space was

surrounded by a distant landscape providing no distinctive cues. Three buildings and 17

landmarks were located in different places within the grid of streets. The buildings were a

“railway station” (A), a “store” (B), and an “apartment building” (C). They were extracted

from a VE designed by Gyselinck, Picucci, Nicolas and Piolino (2006). The three buildings

were not visible from each other. The landmarks were a section of railing, a bus shelter, a

streetlight, an old car, a fountain, a bench, a slide, a bin, a white car, a tree, a dog, a billboard,

a statue, a road sign, a bicycle, a pedestrian, and a traffic light.

During familiarization and the first two phases (memory for landmarks and route

learning), the VE was presented such that the participants could not explore the whole space.

Barriers were used to signal the roads that were not available on a particular route. In the

familiarization version of the VE the shortest route between the station (A) and the store (B)

(route AB) was demonstrated by using visible barriers that blocked all but the correct path.

In the other familiarization version of the VE, the barriers signified the shortest route between

the station and the apartment building (C) (route AC). During learning, the VE was

presented in the same manner as at familiarization, except that the barriers were not visible.

That is, when a participant attempted to walk down an incorrect path, the barrier appeared,

blocking their way (the barriers were located two meters away from the intersection). During

the test phase, the participant could walk along any street in the VE (the barriers no longer

existed).

The VE was projected onto a 1.20 × 1.50 m screen. The distance between the screen

and the participant was 2 meters. Participants navigated from a first person viewpoint, at a

constant velocity. They controlled their movement using the keyboard and the mouse.

WAYFINDING IN DOWN SYNDROME 11

Pressing the space bar effected forward movement and moving the mouse to the right or left

controlled rotational movements.

2.3 Procedure

In a preliminary phase, participants were asked to practice moving along the paths in

the VE using the space bar and the mouse (route AB or route BC), counterbalanced

across the participants. When they were proficient at controlling their movement, the

experiment started. All the participants were able to control their movement through the maze

after a short period of practice. The test session was composed of three phases, each of them

assessing a major component of spatial navigation: memory for landmarks, route learning and

finding a shortcut.

2.3.1 Memory for landmarks.

Participants faced the station and were told to follow the route from the station to the

store (or from the station to the apartment) and then return to the station. The order of the

routes was counterbalanced, with half the participants in each group walking from the station

to the store first (route AB), and the other half walking from the station to the apartment

building first (route AC). The experimenter asked the participants to take their time and to

pay close attention to their surroundings as they walked the route. Each route was constrained

by visible barriers that prevented participants from taking an incorrect path. The participants

walked each route forwards and back twice. Then, after each route, participants were

presented with eight slides showing landmarks in random order. Four of the slides showed

landmarks located along the route that the participants had just walked, and four showed

landmarks located elsewhere in the town. For each of the slides, the participants were asked

to say if they had seen the landmark on the slide along the route that they had just walked.

2.3.2. Route learning.

WAYFINDING IN DOWN SYNDROME 12

Participants faced the station and were asked to find the route between the station and

the store (or the apartment) without choosing a wrong path. The order of the routes was

counterbalanced across participants. When participants entered an incorrect path, a barrier

appeared, preventing the participant from going further. The trial was repeated until

participants reached a criterion of walking the route forwards and back twice without any

errors. The maximum number of learning trials was ten round trips. Participants who passed

the criterion on both routes (AB) and (AC) were asked to find a shortcut between the

routes.

2.3.3 Finding a shortcut.

This phase began with the participants facing the store. They were told they could

walk along any street, and no barriers would appear. They were asked to find the shortest

route between the store and the apartment (B => C). The trial was repeated until participants

walked the shortest route between the store and the apartment twice. No feedback was

provided. This phase was stopped after ten trials for participants who were not able to find

the shortcut. The route explored by the participant was automatically recorded. The walked

distance was also computed.

3. Results

Analyses were carried out using SPSS 18.0. As the data did not consistently meet the

assumptions of normality (Shapiro-Wilk's test), it was analysed using non-parametric tests.

We used the Kruskal-Wallis test to evaluate differences in medians among the three groups.

When the test was significant (p<.05), we conducted pairwise comparisons using the Mann-

Whitney U test.

3.1 Memory for landmarks

The numbers of correctly recognized landmarks in routes (AB) and (AC) were

summed (including hits and correct rejections, max = 16). The Kruskal-Wallis test indicated

WAYFINDING IN DOWN SYNDROME 13

there was a significant difference among the groups, χ2 (2, N=30) = 10.99, p=.004. Pairwise

comparisons indicated that the DS group recognised significantly less landmarks than the CA

and the MA groups (see Table 1, Mann–Whitney U test, respectively: p=.003 and p=.01). The

difference between the CA and the MA groups was not significant (p=.39).

3.2 Route learning

All 10 participants in the CA group reached the criterion of two consecutive trials

without error for both routes, whilst this was true of 9 out of 10 children in the MA group and

7 out of 10 in the DS group. The numbers of trials to reach the criterion in routes (AB) and

(AC) were summed in these participants. The group effect was significant, χ2 (2, N=26) =

14.00, p<.001. The number of trials was significantly higher in the DS group and the MA

groups when they were compared to the CA group (see Table 1, respectively: p<.001 and

p=.007). There was also a trend for the DS group to need more trials than the MA group to

reach the criterion (p=.086).

Insert Table I about here

3.3 Short cut test

Participants who reached criterion in the route learning phase, took part in the short

cut test (CA: N=10; MA: N=9; DS: N=7). The median walked distances were not different

among the groups during the first trial, χ2 (2, N=26) = 3.57, p=.16. They became

significantly different by the last trial χ2 (2, N=26) = 13.02, p<.001. In this trial, the CA

group walked significantly shorter distances than the DS or the MA groups (see Table 1,

respectively: p<.001 and p<.01). Walked distances significantly decreased between the first

and the last trial for the CA group and the MA group (Wilcoxon one-tailed test, respectively:

p=.002 and p=.03). In the DS group, there was a trend for the walked distance to decrease

WAYFINDING IN DOWN SYNDROME 14

between the first and the last trial (p=.07). All participants in the CA group found the shortcut

when walking from the store to the apartment building (route B => C). In contrast, only 5 out

of 9 in the MA group found the shortcut, and only 2 out of 7 in the DS group. When the data

from the participants who found the shortcut was excluded from the statistical analyses, the

trial effect for walked distance was no longer significant in either MA or DS groups (p=.50)

Qualitative data analysis of the performance of participants with DS who did not find

the shortcut revealed that most of them found a relatively long path to reach the destination

and tended to follow it over trials. Indeed they used the same path in 48% of trials (35% for

the MA group). Moreover, in 35% of trials, they combined the two known routes to reach the

destination (15% of trials in MA group). They walked the route towards the station, but when

they arrived at the junction where the two known routes met, they continued their way along

the second known route to reach the store. They did (B => A => C) instead of (B => C).

4. Discussion

The aim of this research was to study memory for landmarks, route learning and

shortcut performance in individuals with DS. It was difficult to predict how well the DS

participants would perform on the test of memory for landmarks. Indeed, assessment of

visual memory in individuals with DS has shown mixed results, with evidence of

performance at the same level as typically developing children of the same mental age in a

colour memory task (Laws, 2002), but poorer performance than mental age matched controls

on a visual object memory task (Vicari, Bellucci & Carlesimo, 2006). Our results were more

in line with Vicari et al.’s results (2006), with the DS group recognizing significantly fewer

landmarks than the CA and MA groups. This result is surprising since their performance in

the learning phase suggested that they could use the landmarks to learn new routes. Yet, the

memory test took place between the familiarization phase and the learning phase. A plausible

explanation may be that individuals with DS paid less attention to landmarks than the TD

WAYFINDING IN DOWN SYNDROME 15

children during the familiarization phase since they simply had to follow the route. Future

research could test memory for landmarks at the end of the learning phase.

As expected, most of the participants with DS were able to learn the two routes, even

though they needed more trials than the CA controls to reach the criterion. These participants

may have achieved this performance by using alternative strategies. A first strategy may have

involved the memorization of the ordered sequence of landmarks and actions to be taken.

This strategy could not be based on a simple association of each landmark with a unique

response (i.e. response learning), since the routes were walked both forwards and backwards.

However, there were only four changes in direction in each round trip. Individuals with DS

may have memorized a sequence of this length. Indeed, there is evidence that the spatial

sequential working memory is relatively preserved in DS. Lanfranchi, Carretti, Spano and

Cornoldi (2009) found that individuals with DS performed at the same level as TD children

of the same MA in a 2D task where they had to recall pathways. A second strategy may have

involved a beacon-following procedure (Montello, 2005). Individuals using this strategy may

have looked for a known landmark in the local surround, moved toward it, and then looked

for another known landmark. This strategy may have been effective in the environment we

used. Further research is needed to better understand the precise nature of route learning

strategies in individual with DS. This can then inform interventions. For example, if

individuals with DS remember a sequence of turns along a route, but pay little attention to

landmarks, their success will be limited to very short routes. Teaching these individuals to

attend to landmarks and to associate landmarks with actions might improve their route

learning ability.

Did individuals with DS encode the spatial layout of the environment during the

learning phase? Our assumption was that their deficit in place learning (Pennington, et al.,

2003) would impair their ability to create a configurational representation of their

WAYFINDING IN DOWN SYNDROME 16

environment. As expected, results from the shortcut test suggested that most of them did not

develop a configurational representation of the environment. Only two participants with DS

were able to find the shortest route between the store and the apartment whereas all of the

participants in the CA group found the shortcut. Based on Pennington et al.’s (2003) results

on a virtual Morris water maze, we also expected individuals with DS to perform less well

than the MA control group in the shortcut task. The results did not support this hypothesis.

Results rather suggested that children in the MA group also had difficulties in developing a

configurational representation of the environment. They performed less well than participants

in the CA group and half of them did not find the shortcut. This result is consistent with

Schmelter, Jansen and Heil (2009), who assessed spatial knowledge acquisition in a real and

a virtual large-scale environment. They found that 7-8 year old children showed less

configurational knowledge than older children (11-12 year-olds) and adults. Interestingly,

their results also suggested that the developmental process in spatial knowledge was

comparable across real and virtual environments.

Finally, it is important to note that the DS participants who did not find the shortcut

did not fail to navigate from B to C. Most of them found a relatively long path to reach the

destination and tended to follow it over trials and some of them combined the two known

routes to reach the destination (B => A => C). These participants were engaged in a goal

directed and planned activity, however they lacked the configurational knowledge allowing

them to find short paths. This should be taken into account when working with individuals

with DS; a lack of configurational knowledge can, at least in many circumstances, be

compensated for by piecing together parts of known routes.

Could familiarity with playing computer games account for these results? A limitation

of the present experiment was that we asked the participants whether they had experience

with computer games without recording how often they played these games. We thought

WAYFINDING IN DOWN SYNDROME 17

participants with DS would have had difficulties in answering such a question. Familiarity

with computer games may help participants to carry out task in VE, however results from

developmental research suggest that this factor is not a determining factor for learning in a

VE. Jansen-Osmann and Wiedenbauer (2004) asked second graders, sixth graders and adults

to learn a route through a virtual maze and to recall landmarks (the mean age were

respectively: 7.8; 11.8; 25.9). They also asked the participants how often they played

computer games (in hours per week). The younger children made more errors, walked much

longer distances, and recalled less landmarks that older children and adults (in the landmarks

test, the participants had to walk through an empty maze recalling the names and the

positions of the landmarks). However, a lower experience in computer game could not

account for the results since the second and sixth graders played computer games more often

than adults (there was no significant differences between the two groups of children).

The current results suggest that most individuals with DS could acquire knowledge

about specific routes without being able to integrate that knowledge into a configurational

understanding. However, we also found individual differences in this group. Some

participants were unable to learn the routes; others could learn the routes, but their

wayfinding behaviour was not flexible; and very few of them were able to find the shortcut.

Future research should include investigating whether the variations we found are also found

in wayfinding behaviour in real environments.

WAYFINDING IN DOWN SYNDROME 18

ACKNOWLEDGEMENTS

This research was supported by the Fondation Jérôme Lejeune (France) and the ANR-ESRC

research program (ANR-FRBR-035 ELSTRAD). Thanks go to Vincent Sockeel for

programming the VE. We also wish to thank all the participants for taking part in the study.

WAYFINDING IN DOWN SYNDROME 19

REFERENCES

Bittles, A. H., Bower, C., Hussain, R., & Glasson, E. J. (2007). The four ages of Down

syndrome. The European Journal of Public Health, 17(2), 221-225.

Chapman, R. S. (1997). Language development in children and adolescents with Down

syndrome. Mental Retardation and Developmental Disabilities Research Reviews,

3(4), 307-312.

Cognet, G. (2006). Manuel de la NEMI-2. Paris: ECPA.

Facon, B., Magis, D., & Courbois, Y. (2012). On the difficulty of relational concepts among

participants with Down syndrome. Research in Developmental Disabilities, 33(1), 60-

68.

Frenkel, S., & Bourdin, B. (2009). Verbal, visual, and spatio-sequential short-term memory:

assessment of the storage capacities of children and teenagers with Down's syndrome.

Journal of Intellectual Disability Research, 53(2), 152-160.

Gyselinck, V., Picucci, L., Nicolas, S., & Piolino, P. (2006). Construction of a spatial mental

model from a verbal description or from navigation in a virtual environment.

Cognitive Processing, 7, 46-48.

Hegarty, M., Montello, D. R., Richardson, A. E., Ishikawa, T., & Lovelace, K. (2006).

Spatial abilities at different scales: Individual differences in aptitude-test performance

and spatial-layout learning. Intelligence, 34(2), 151-176.

Hunt, E., & Waller, D. (1999). Orientation and wayfinding: A review. Arlington, VA: Office

of Naval Research.

WAYFINDING IN DOWN SYNDROME 20

Jansen-Osmann, P., & Wiedenbauer, G. (2004). The representation of landmarks and routes

in children and adults: A study in virtual environment. Journal of Environmental

Psychology, 24, 347-357.

Jarrold, C., & Baddeley, A. D. (1997). Short-term memory for verbal and visuospatial

information in Down's syndrome. Cognitive Neuropsychiatry, 2(2), 101-122.

Jarrold, C., Thorn, A. S. C., & Stephens, E. (2009). The relationships among verbal short-

term memory, phonological awareness, and new word learning: Evidence from

typical development and Down syndrome. Journal of Experimental Child Psychology,

102(2), 196-218.

Lanfranchi, S., Baddeley, A., Gathercole, S., & Vianello, R. (2012). Working memory in

Down syndrome: Is there a dual task deficit? Journal of Intellectual Disability

Research.

Lanfranchi, S., Carretti, B., Spano, G., & Cornoldi, C. (2009). A specific deficit in

visuospatial simultaneous working memory in Down syndrome. Journal of

Intellectual Disability Research, 53(5), 474-483.

Lanfranchi, S., Cornoldi, C., & Vianello, R. (2004). Verbal and visuospatial working memory

deficits in children with Down syndrome. American Journal on Mental Retardation,

109(6), 456-466.

Laws, G. (2002). Working memory in children and adolescents with Down syndrome:

evidence from a colour memory experiment. Journal of Child Psychology and

Psychiatry and Allied Disciplines, 43(3), 353-364.

Mangan, P. A. (1992). Spatial memory abilities and abnormal development of the

hippocampal formation in Down syndrome. Unpublished Unpublished doctoral

dissertation, University of Arizona, Tucson.

WAYFINDING IN DOWN SYNDROME 21

McDonald, T. P., & Pellegrino, J. W. (1993). Psychological perspectives on spatial cognition.

In T. Gärling & R. G. Golledge (Eds.), Behavior and Environment: Psychological and

Geographical Approaches (pp. 47-82). Amsterdam: Elsevier Science Publishers.

Mengue-Topio, H., Courbois, Y., Farran, E. K., & Sockeel, P. (2011). Route learning and

shortcut performance in adults with intellectual disability: A study with virtual

environments. Research in Developmental Disabilities, 32, 345-352.

Montello, D. R. (2005). Navigation. In P. Shah & A. Miyake (Eds.), The Cambridge

Handbook of visuospatial thinking (pp. 257-294). Cambridge: Cambridge University

Press.

Nadel, L. (2003). Down's syndrome: A genetic disorder in biobehavioral perspective. Genes,

Brain and Behavior, 2(3), 156-166.

Naess, K.-A. B., Lyster, S.-A. H., Hulme, C., & Melby-Lervag, M. (2011). Language and

verbal short-term memory skills in children with Down syndrome: A meta-analytic

review. Research in Developmental Disabilities, 32(6), 2225-2234.

Numminen, H., Service, E., Ahonen, T., & Ruoppila, I. (2001). Working memory and

everyday cognition in adults with Down's syndrome. Journal of Intellectual Disability

Research 45(2), 157-168.

Pennington, B. F., Moon, J., Edgin, J., Stedron, J., & Nadel, L. (2003). The neuropsychology

of Down syndrome: Evidence for hippocampal dysfunction. Child Development,

74(1), 75-93.

Previc, F. H. (1998). The neuropsychology of 3-D space. Psychological Bulletin, 124(2),

123-164.

Previc, F. H., Declerck, C., & de Brabander, B. (2005). Why your "head is in the clouds"

during thinking: The relationship between cognition and upper space. Acta

Psychologica, 118(1-2), 7-24.

WAYFINDING IN DOWN SYNDROME 22

Roubertoux, P. L., & Kerdelhué, B. (2006). Trisomy 21: From chromosomes to mental

retardation. Behavior genetics, 36(3), 346-354.

Schmelter, A., Jansen, P., & Heil, M. (2009). Empirical evaluation of virtual environment

technology as an experimental tool in developmental spatial cognition research.

European Journal of Cognitive Psychology, 21(5), 724-739.

Uecker, A., Mangan, P. A., Obrzut, J. E., & Nadel, L. (1993). Down syndrome in

neurobiological perspective: An emphasis on spatial cognition. Journal of Clinical

Child Psychology, 22(2), 266-276.

Vicari, S., Bellucci, S., & Carlesimo, G. A. (2006). Evidence from two genetic syndromes for

the independence of spatial and visual working memory. Developmental Medicine &

Child Neurology, 48(2), 126-131.

Visu-Petra, L., Benga, O., & Miclea, M. (2007). Visual-spatial processing in children and

adolescents with Down's syndrome: A computerized assessment of memory skills.

Journal of Intellectual Disability Research, 51(12), 942-952.

WAYFINDING IN DOWN SYNDROME 23

Fig. 1. Map of the virtual environment (A = the railway station; B = the store; C = the

apartment building; circles = landmarks; dashed line = routes [AB] and [AC]; solid line

= the shortcut).

A

B

C

WAYFINDING IN DOWN SYNDROME 24

Table 1. Results from the three experimental phases

(DS = Down Syndrome, MA = mental age, CA = chronological age; interquartile ranges are

in brackets).

DS MA CA

Phase 1:

Memory for

landmarks

Median number of

correctly recognized

landmarks (max = 16)

10.5 (4.25)

13 (2.25)

13.5 (1.75)

Number of

participants who

reached the learning

criterion (max = 10)

7

9

10

Phase 2: Route

learning

Median number of

trials to reach

criterion (max = 20)

9 (3)

6 (4)

4 (1)

First trial: Median

walked distance

760 (1564) 523 (454) 425 (591)

Last trial: Median

walked distance

405 (446) 337 (222) 277 (11)

Phase 3:

Shortcut

Number of

participants who

found the shortcut

2

5

10