[2011][sunderland_iin]Tool use and action planning in apraxia

Neuropsychologia 49 (2011) 1275–1286
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Neuropsychologia
journal homepage: www.elsevier.com/locate/neuropsychologia
Tool use and action planning in apraxia
Alan Sunderlanda,∗
, Leigh Wilkinsa
, Rob Dineenb
a
School of Psychology, University of Nottingham, Nottingham NG7 2RD, United Kingdom
b
Division of Academic Radiology, University of Nottingham, Nottingham, United Kingdom
a r t i c l e i n f o
Article history:
Received 15 October 2010
Received in revised form
15 December 2010
Accepted 11 January 2011
Available online 15 January 2011
Keywords:
Apraxia
Tool-use
Memory for actions
Action planning
Left inferior parietal lobe
a b s t r a c t
Apraxia after left inferior parietal lesions has been widely interpreted as evidence of damage or impaired
access to representations of tool-use, but most research has investigated pantomime of tool actions, not
handling of actual tools. An alternative account is that inferior parietal damage does not affect tool-
use representations but impairs cognitive processing about postural and hand-tool spatial relationships
which is necessary for planning and controlling any complex action. Four apraxic patients and 10 age-
matched controls were asked to reach rapidly for tools or abstract objects of similar dimensions. Under
conditions of time pressure and divided attention, the patients frequently failed to invert the hand to
grasp inverted tools by the handle, whereas ability to invert the hand to avoid a barrier and grasp abstract
objects was largely unimpaired. Frequency of errors in tool grasping correlated with severity of apraxia.
When inverted tools were correctly grasped, rotation of the wrist occurred later during the reaching
movement than when inverting the hand to grasp an abstract object. These data are consistent with
the theory of degraded access to tool-use representations in apraxia, but this theory cannot account for
co-occurring deficits in imitating or matching meaningless hand or body postures.
© 2011 Elsevier Ltd. All rights reserved.
1. Introduction
Skilled use of tools is a fundamental human ability which is cru-
cial to functioning in everyday life. Reaching for a tool requires
integration of control of movement with selection of a grasp that
is appropriate for its use. Take for example picking-up a spoon to
put sugar in coffee. This requires not just that we control reaching
to grasp accurately an object of certain physical dimensions, but
also that it is grasped by the handle and with the bowl of the spoon
downwards. The brain processes involved in such actions are still
poorly understood but there is evidence from functional imaging to
suggest that the left posterior temporal and inferior parietal areas
contain representations of actions associated with familiar tools
(Vingerhoets, 2008). There is also evidence from effects of brain
lesions in these areas which seems consistent with this conclusion
(Buxbaum, Kyle, & Menon, 2005). However, a difficulty in inter-
pretation of the patient data is that it comes from patients with
apraxia, who show not just abnormalities in tool-use but also more
widespread problems in action production. This raises the ques-
tion of whether apraxic patients’ difficulties with tools are due to
damage to representations of tool-use, or whether they arise from a
more general problem affecting production of any complex action.
In this paper we report an experiment comparing how apraxic
∗ Corresponding author. Tel.: +44 0115 8467273; fax: +44 0115 9515324.
E-mail address: [email protected] (A. Sunderland).
patients reach to grasp tools or to grasp abstract objects. This leads
to the conclusion that interaction with tools is selectively impaired,
but perhaps not because of damaged action representations.
The most common apraxic syndrome is usually termed ideo-
motor apraxia (IMA) and is a frequent consequence of left middle
cerebral artery stroke, especially when there is damage to the
left inferior parietal lobe (Buxbaum, Kyle, Grossman, & Coslett,
2007; Weiss, Rahbari, Hesse, & Fink, 2008). The defining feature
is difficulty in performing gestures in response to verbal com-
mand (e.g. “Show me how you would salute”) and when imitating
the examiner. The most prominent errors are abnormalities in the
configuration of the final posture (Hermsdorfer, Mai, Marquardt,
Veltkamp, & Goldenberg, 1996), such as placing the wrist in contact
with the forehead instead of the fingers when saluting. Most cases
also show difficulties in producing tool actions, especially when
asked to pantomime the action without the constraining influence
of the tool in hand (Goldenberg, Hentze, & Hermsdorfer, 2004).
For example, when asked to pantomime how a hammer would
be used, making a downward gesture with a fist rather than pre-
tending to be holding a handle. This has been interpreted by many
authors as evidence of damage or impaired access to tool-use rep-
resentations: Heilman, Rothi, and Valenstein (19...