Shallice and B urgess (1991a) propose th a t the inability to find su b stan tial and consistent deficits in those with frontal lesions is because:
"The relevant tests were not given to the p a tie n t"
Shallice and Burgess, 1991a p727
Although it is Shafiice and B urgess (1991a) who are the m ost recent investigators to draw our attention to the problem of relevant tests, Goldstein (1936a) previously suggested:
"...changes characteristic o f the frontal lobe are o f a definite type and m ay be easily overlooked, because the m ethods o f examination usually em ployed are unsuited to disclosing them."
Goldstein, 1936a p.28.
Many early researchers suggested the frontal lobes had few, if any, intellectual functions, or at least no special role in the adult
(Feuchtwanger, 1923; Pfeifer, 1910). Again, th is was probably a consequence of limited neuropsychological assessm en t with inappropriate m easures. The questions th a t m u st be answered, however, are w hat are the relevant te sts ? And even though researchers should now be aware of these difficulties, have the m ethods of assessm en t altered ?
Many studies have reported on the paradox of patients with widespread frontal lobe dam age whose perform ance on tests
thought sensitive to su ch damage was good, yet showed poor day to day functioning (eg Brickner, 1936; Penfield an d Evans, 1935). For example, Heck an d Bryer (1986) report on a case of bilateral frontal lobe atrophy. They reported th a t despite the social and working life of the patient being severely restricted by her
behavioural characteristics, her performance on stan d ard m easures of intellectual functioning and on te sts of sorting an d categorising (Wisconsin Card Sorting Test an d the H alstead Category Test) was extremely good. Unfortunately, the su b ject’s perform ance on other m easures was not reported.
Eslinger an d Damasio (1985) reported on an individual, EVR, who developed profoundly abnorm al personality characteristics following the surgical removal of a large orbitofrontal meningioma. Prior to the appearance of the tum our and its surgical removal a t the age of 35, EVR was a norm al individual, having been a successful
accountant rising to become a senior partner.
Following a three m onth post-surgical recovery period EVR
returned to work. However, EVR was soon troubled- losing all his money in a failed b u siness partnership. Thereafter he drifted
Employers complained about his tard in ess an d disorganisation despite his Job skills being more th a n adequate. Similar difficulties led to a deterioration in his m arital life, u ntil h is wife left with the children an d filed for divorce.
In short, EVR's decision m aking and planning were (i) qualitatively different from w hat they were before, an d (ii) clearly defective by reference to his own sta n d ard s a s well as those of his direct peers. Against th is background, EVR's neuropsychological perform ance was norm al. Indeed, on m easures of intellectual functioning he scored above average. Similarly, EVR's performance on tests of language processing was fully preserved. On te sts of memory an d perception EVR's performance was also unim paired.
Furtherm ore, EVR also lacked some supposedly characteristic signs of frontal lobe dysfunction. For instance EVR produced perfect scores on the WCST, the Category Test, and the Word Fluency test, an d his performance on te sts of cognitive estim ation and
judgem ents of recency an d frequency were flawless.
A further dissociation of intact cognitive skills an d socially driven behaviour h as been reported in 3 patients with frontal lobe lesions by Shallice an d B urgess (1991a). In short these patients generally scored well on tests of general intellectual functioning, language, memory and, m ost relevantly, te sts thought sensitive to frontal lobe dysfunction (including bim anual h an d movements, cognitive
estim ates, proverb interpretation. Tower of London test. Trail
m aking test, verbal fiuency, MWCST). However, the patients' day-to- day behaviour was characterised by disorganisation, tardiness, and lim ited motivation (see previous discussion in ch ap ter 7).
More recently, Goldstein et al (1993) reported the case of an
individual with a left frontal excision who dem onstrated poor day to day perform ance b u t whose perform ance was com petent on the traditional m easures thought sensitive to frontal dysfunction. Indeed, th e au th o rs comment:
''The absence o f form al neuropsychological te st decrem ent cannot be taken a s definitive evidence o f the absence o f deficits p er se."
Goldstein e t al, 1993 p. 276
All of these case exam ples dem onstrate th a t the neuropsychological m easures developed for assessing frontal lobe dysfunction do not show particularly good validity. Indeed, the case exam ples described all had severe abnorm alities of the frontal lobes, often with bilateral dam age (eg Eslinger and Damasio, 1985; Heck an d Bryer, 1986). If the traditional neuropsychological te sts employed were unable to reveal deficits in cases such as these, th en the likelihood of
detecting deficits in individuals with sm aller, more subtle dam age seem s limited.
Many researchers have com m ented upon the lack of clinical
m easures exclusively sensitive to frontal lobe function. For example, Wang (1987) h a s concluded th a t we are still in "search for a
sensitive frontal lobe test" (p. 203). Similarly, Damasio (1985) sta tes, with reference to frontal lobe damage:
"The standard behavioural m easurem ents available a t bedside or in the neuropsychology laboratory are sim ply not adequate to address the disturbances"
Damasio, 1985 p. 340
A num ber of frontal tests have been reported over the years b ut aU currently lack reliable normative data an d require more extensive em pirical support for the view th a t they indicate frontal type
im pairm ent (Parker and Crawford, 1992). Sum m arising their review of the m ethods currently available to assess frontal lobe function Parker and Crawford suggest:
"The major conclusion that one can fa irly reach
following a review o f a sse ssm en t procedures fo r fro n ta l dam age is that there are disappointingly f e w sensitive a nd reliable tests which the clinical neuropsychologist can depend on."
Parker and Crawford, 1992, p286
It is therefore reasonable to conclude th a t tapping the functions of the frontal lobes h as proved extremely difficult in both a clinical an d research setting. Many tests have been employed, yet none h as
proved entirely satisfactory, and consequently the choice of te sts is usually based upon familiarity an d personal preference (Parker and Crawford, 1992). Some of the more popular tests suggested to be sensitive to frontal lobe dysfunction are listed in table 8.1 an d their relative m erits, or otherwise, outlined (see also Anderson, 1994 an d Parker an d Crawford, 1992).