ACQ Vol 13 no 2 2011

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ACQ Volume 13, Number 2 2011 75
In addition, there are some common pitfalls that need to
be avoided when measuring change over time. Of course,
one can only truly evaluate whether a change has occurred
if one measures performance on the same test, because
of differences in test difficulty. Hence, at each assessment
the same test (and the same items within a test) should
be used to measure, for example, semantics, naming,
repetition, reading. Moreover, should different items be
completed on each occasion (e.g., a smaller number of
items tested on the second assessment than the first), then
the true extent of change can only be evaluated through
comparing performance on those items that were assessed
on both testing occasions. It is therefore important to
choose, wherever possible, assessment tasks that are
sensitive to a range of severities. Alternatively, if it is not
possible to use the same test and the same items on each
occasion, at least one testing session should use both
a harder and an easier test, prior to no longer using the
harder test. One final point to note is that some relatively
easy tests (e.g., PALPA word-picture matching, subtest 47)
may appear to give a picture of no change in performance
when an individual is scoring close to ceiling (i.e., close
to the maximum possible on the test). However, despite
the lack of change in the score, a decline in the underlying
skill may have occurred (e.g., semantic processing in
PALPA 47). This is because on some assessments, even
if language skills are impaired, it is still possible to score
perfectly.
It is important to also consider issues of reliability and
sensitivity in relation to assessment beyond the impairment
level. For example, it is only when sufficient detail has
been documented regarding the nature of participation
and communicative activities undertaken, that change
can accurately be tracked in that participation. To return
to our example of using the telephone: that an individual
has difficulty in using the telephone may be too general
a measure to be able to detect any change. However, if
more detailed questioning had provided greater detail as
to the extent and nature of the difficulty, then it may have
been possible to determine whether there had indeed been
a change over time in the degree of difficulty in telephone
use. Incorporating client ratings into the extent of difficulty
or depth of feelings can also add sensitivity.
Tracking change as a result of treatment
In the treatment of non-progressive aphasia, it is important
that any assessment of treatment outcomes must show (a)
whether the ability being treated is changing over the
course of treatment, and (b) whether the change is actually
due to the treatment as opposed to some other factor that
happens to influence the outcome (Nickels, 2002; Wilson,
1987). While these are clearly also relevant to treatment of
progressive aphasia, the situation is complicated because
of the expectation of decline without treatment. Although
improvement above the level seen at initial assessment is
one possible outcome if therapy is effective, it is not the
only one. One might also see an outcome of no change
(i.e., the client maintains his or her current level of ability), or
a slowing of deterioration that allows the individual to
continue in desired activities for a longer period of time than
would have been possible without the intervention (Rapp &
Glucroft, 2009). To know whether a treatment is effective,
the ability being treated must also be compared with a
“control” condition (perhaps items of similar difficulty that
are not being treated, or another ability that is not expected
allow for in-depth discussion of concerns, priorities, and
goals, but also to gain an understanding of the nature of
the functional impact of language impairments (e.g., not
just that there is a problem with using the telephone, but
just how this problem manifests itself). As Simmons-Mackie
and Damico (2001) point out, clinicians routinely do obtain
information from clients and families regarding activities,
social relationships, and feelings. However, critically, this
information is rarely documented systematically, rendering it
a far less potent source of information.
In sum, we advocate hypothesis-driven assessment and
systematically documented in-depth interviews as the most
efficient way of identifying the current status of language
impairment and function and of enabling truly collaborative
treatment planning for people with progressive aphasia.
To investigate change over time
Unfortunately, it is central to the nature of the disorder that
people with progressive language impairments will show a
decline in their language functions over time. An important
role for the speech pathologist is therefore to track this
decline in order that the rate and nature of change can be
used to plan for future communication strategies and adjust
the focus of treatment. For example, if one skill (e.g.,
writing) is declining at a more rapid rate than another (e.g.,
spoken output), a communication strategy that relies on a
rapidly declining skill would seem to be ill advised, but an
impairment-directed treatment aimed at maintaining this
skill may be important (depending on the personal priorities
of the individual). The speech pathologist might also provide
education about the need for strategies that proactively
address the potential consequences of further decline in
that ability (e.g., how will the client handle future
management of personal, health, legal, and financial
matters which currently rely on writing?). In addition, as with
any client group, it is vital to evaluate the nature of the
change brought about through treatment.
Choosing assessments for tracking change
In order that assessments can accurately document
change (both spontaneous change and change brought
about through treatment), they must be reliable (i.e., if there
is no change they will show the same level of performance
on retest) and sensitive (i.e., if there is change this will be
reflected in the scores) (Howard & Hatfield, 1987). Both of
these criteria require a relatively large sample of behaviour
(e.g., many items to name aloud, many observations of
attempted conversational repair; multiple ratings of similar
communicative behaviours – ordering a pizza, ordering a
taxi, ordering a curry). The adequacy of the sample is
another factor to consider when evaluating the suitability of
a general language battery for use in assessment of
progressive aphasia. While over the battery as a whole
there are usually large numbers of stimuli, within each
subtest the numbers of items are generally (and necessarily)
small. Thus change in a specific skill as a result of a greater
rate of decline, or as a result of improvement, if therapy has
been targeted at that area, may neither be represented in
the overall score nor be significant on its own because of
the small number of stimuli. Hence, our recommendation
would be, wherever possible, to use specialised
assessments that are aimed at each level of processing of
interest and that contain enough stimuli to enable sensitivity
and reliability in the measurement of change as and when it
occurs.