Brain Development: Normal Processes and the Effects of Alcohol ...

132 ETHANOL-AFFECTE D DEVELOPMENT
et al, 1996; Kerns étal, 1997 ; Schonfel d étal, 2001;
Willford e t al, 2004). A longitudinal follow-u p study
of 14-year-olds shows that verbal-auditory rathe r than
visuospatial memor y i s affected wit h learning ; short -
and long-ter m memor y deficits on a paired associate
task are detected (Willfor d et al, 2004) . I n a sampl e
of adolescents an d youn g adult s classifie d a s having
an "averag e IQ " o r "belo w averag e IQ, " Kern s an d
colleagues (1997 ) show that individuals with FAS perform
belo w expectation o n the CVLT-C. The greates t
difference i s not o n initia l learning trials, but o n th e
fifth trial. These results suggest that affected individu -
als are not able to use semantic memory strategies appropriately
t o maintain a comparable learnin g slop e
over repeated trials . That is, the individual s with FAS
do not use the categorie s inheren t i n the lists to organize
and facilitate their recal l an d thei r response s do
not sho w the clusterin g o f semantically related item s
that is usually found i f effective memor y strategies are
used. This findin g contrast s t o a lack of difference i n
primacy effec t an d seria l clustering scores , which re -
lies less on strategy use.
Mattson an d Riley (1999) contras t intentional an d
incidental memor y b y measuring recal l o f information
(a ) whe n childre n wit h FA S ar e awar e o f th e
memory tas k involved and (b ) when the y learn infor -
mation usin g effective memor y strategies provided by
the investigator s without bein g awar e of the nee d t o
learn the information in expectation o f recall. The in -
vestigators conclude tha t incidental memor y is not affected
b y prenatal alcohol exposure.
Coles an d colleague s (1997 ) gav e a n alcohol -
exposed an d a contras t grou p o f 7-year-olds a paire d
associate tas k requirin g tha t th e childre n continu e
with the list-learnin g process until the y achiev e mas -
tery. At both immediat e an d delaye d recall , alcohol -
affected childre n ar e no t differen t fro m control s with
this methodology . Th e numbe r o f repetition s re -
quired t o achiev e lis t mastery , however , i s signifi -
cantly higher for alcohol-affected children .
Cumulatively, the abov e findings suggest that one
aspect o f th e memor y defici t observe d i n alcohol -
affected individual s involves employing strategies. That
is, they may not be exhibiting effective "metarnemory "
(an important aspect of executive functioning) in tha t
they ma y hav e mor e difficult y i n selectin g an d em -
ploying effective learnin g strategies and the y may not
be aware of the level of effort required t o achieve mas -
tery on a particular task. It may also be tha t becaus e
alcohol-affected individual s process informatio n mor e
slowly, learning time is spent less efficiently an d mor e
trials are required. Whether these deficit s are uniqu e
to individuals with FAS D o r are characteristic of slow
learners in general i s not clear and should b e the sub -
ject of further study .
An aspect of memory that is considered a factor in
executive processin g i s active working memory. This
process involve s menta l manipulatio n o f element s
stored briefl y i n short-term memor y and has been referred
to as a "mental scratc h pad " (Ashcraft , 1995) . It
requires that informatio n be store d an d processe d i n
meaningful "units " at a given moment in time. Man y
of the cognitiv e task s comprising neurodevelopnien -
tal tes t batterie s includ e us e o f active working mem -
ory because higher-order processing or problem solving
requires tha t severa l unit s o f informatio n b e main -
tained simultaneously .
In alcohol-affected individuals , problems i n active
working memor y hav e bee n identifie d earl y i n in -
fancy. Usin g a visua l expectanc y paradig m (Hait h
et al. , 1988 ; Jacobson e t al. , 1992 ) as a measur e o f
working memory, Was s and Hait h (1999 ) show that 3month-old
infants exposed to alcohol prenatally have
more difficult y tha n nonexpose d control s i n main -
taining an d manipulatin g three item s of information
simultaneously, a result implying a reduction i n working
memory capacity . On th e same task, these infant s
have difficultie s shiftin g fro m on e rul e t o anothe r
(that is , learning to anticipate wher e item s woul d b e
presented next ) an d wit h masterin g comple x spatia l
sequences. Kodituwakk u an d colleague s (1995 ) use d
several neurodevelopmental tasks tapping activ e working
memory in older individuals. They conclude that a
problem i n managing goal s i n working memory i s the
mechanism underlyin g much o f the cognitiv e impairment
see n i n childre n wit h FAS . I n practica l terms ,
such a defici t wil l affec t dail y functionin g an d academic
performanc e a s well a s results of neuropsychological
tests. For instance, children diagnosed with FAS
consistently sho w impairment s i n doing mathematics ,
as demonstrate d b y performanc e o n th e arithmeti c
subtests from the Wechsler series (e.g., Wechsler, 1991)
of intelligence tests . These tests rel y heavily on activ e
working memor y skill s by requiring the manipulatio n
of number s an d arithmeti c operation s i n short-ter m
memory to generate correct answers .
Planning an d Organization . Peopl e wit h FAS D
are described a s having impairments in planning, organization,
an d problem-solvin g aspect s o f executiv e