CALIDAD DE LOS EMPAQUES DEL PRODUCTO ENVASADO DE

There are a handful of reports on the effects of early prefrontal damage in children and the subsequent behaviour in adulthood of those children. One such patient is JP, described initially by Ackerly (1964; Ackerly and Benton, 1947), who was studied over a thirty year period (Benton, 1991). Scholastically, he was described as average, which was confirmed on formal psychom etric testing. However, his school behaviour was less th a n ideal and was referred to a school guidance clinic:

"because o f repeated incidents over a period o f years such a s masturbation, truancy, stealing fro m children, thrusting h im self into the centre o f attention with no self-

consciousness, excessive boastfulness and extreme unpopularity with his school mates"

Ackerly, 1964 p. 194

As an ad u lt JP exhibited a com bination of traits- am ong them , concrete thinking, impulsivity, weak interpersonal bonds,

equanim ity, an d lack of concern- behaviours clearly suggestive of prefrontal damage. On retrospective exam ination of medical an d school notes it was evident the behaviour recorded in adulthood had also been present in childhood. Surgical exploration revealed cystic

degeneration of the left frontal lobe sparing Broca’s area an d m otor cortex an d a completely atrophied prefrontal region in th e right frontal lobe. These changes apparently dated from an early age (approximately 3 years). However, with a retrospective report it is obviously impossible to date accurately.

In concluding the report, Ackerly (1964) calls for greater clinical studies and other longitudinal case stu d ies of individuals with

sim ilar frontal lesions. This necessity h a s been observed to a limited degree. O ther reports have also suggested th a t dam age su stain ed to the prefrontal cortex in childhood can lead to characteristic

behavioural changes th a t rem ain during adulthood (EsUnger et al, 1989; Eshnger et al, 1990; G rattan et al, 1989; Hebb, 1945; Marlowe, 1989, 1992; Norman, 1945; Price et al, 1990; Russell,

1948; SteUing et al, 1986).

For example, in a report of four cases of children who h ad su stain ed damage to the prefrontal region a t the ages of 3 (2 cases), 7, an d 9 years and followed up for between 3 and 7 years, b ut had not yet reached adulthood (Mateer and WiUiams, 1991), the au th o rs describe behaviours characteristic of "frontal lobe syndrome". However, these behaviours were not observed imm ediately p o st­ injury. Indeed, the im portant changes were not seen u ntil m any weeks or m onths post-injury. The changes in self-regulatory behaviour m anifested as irritability, moodiness, distractibility, impulsivity, an d im paired social aw areness, persisted m any years post-injury, an d in no case was there complete resolution.

In an o th er report. Price et al (1990) reported on two cases who su stain ed injuries in early childhood (0 an d 4 years respectively) and whose behavioural abnorm alities lasted during adulthood. In addition, th ese two cases were im paired on tests of moral

development (Kohlberg, 1976) an d appeared "stuck" a t the

developm ental stage when their injuries occurred. It was further suggested th a t the im pairm ent may be greater w hen lesion occurs in childhood, rath e r th a n adulthood:

"It even appears a s if bifrontal lesions yield behaviours that are more chaotic and aberrant w hen the dam age is acquired early in life rather than during adulthood."

Price et al, 1990, p. 139

The reports so far sum m arised have suggested th a t childhood damage to th e frontal lobes can lead to behavioural changes sim ilar to those seen in adults, and th a t these changes can rem ain in

adulthood with little chance of resolution. The question th a t m u st be posed, however, is why are these observations different from both the biological evidence an d the developm ental cognitive research with norm al children ? That is, th a t the frontal lobes are not fuUy developed until m uch later (age 10 to 12 years) an d th a t lesions prior to this age may be neuropsychologically silent (eg Chugani et al, 1987).

The work of K ennard is im portant in th is regard. Her work suggested th a t prim ates operated on in infancy have a greater capacity for sparing and recovery th a n older anim als on various m easures (Kennard, 1936, 1942, 1944), although this was not always a consistent finding (eg K ennard an d Fulton, 1942). More recently, Chugani et al (1987) have suggested th a t frontal injury during a period of rapid growth in cerebral m aturation resu lts in relative sparing of function because of enhanced plasticity. However, the evidence from the stu d ies conducted with neurologicaUy

dam aged chUdren suggests there is Uttle chance of resolution of dam age to the prefrontal cortex. Indeed, the opposite ap p ears to be the case- early damage leads to behavioural changes th a t are

apparent into adulthood (Levin et al, 1994; Price et al, 1990). One proposal attem pting to resolve these difficulties, is th a t the frontal lobes are continuaUy developing throughout both chUdhood an d adulthood, b u t th a t this does not occur linearly b u t rather, growth sp u rts occur at certain ages (see previous discussion and Thatcher, 1991). Early frontal lobe dam age d isru p ts the m aturation of the developing cerebral regions and d isru p ts both the neu ral and cognitive architecture; th u s early dam age resu lts in disruption of part of a cognitive system and prevents the system from acting a s a unified whole (Grattan an d EsUnger, 1991).

A case study exemplifying th is point was provided by Eslinger et al, 1992 (which raised sim ilar issu es to those of the stu d y of M ateer an d Williams, 1991). They described a thirty three year old woman who su stain ed a spontaneous intraparenchym al haem orrhage of unknow n cause in the left frontal region a t the age of seven years. After the injury, the only noted difficulty was slower rate of

academ ic learning. Three to five years after the lesion occurred, however, the patient's adjustm ent appeared to decline an d social im pairm ent became more obvious as she encountered progressively more complex social situations. She was prom iscuous, hyper-

religious, was unable to care for herself, her home or her child, an d w as unable to hold down full time employment and m ade several unsuccessful applications for jobs she was not qualified for, on the basis th a t they "looked interesting" (a sim ilar observation, perhaps notably, was also made by Harlow, 1868 and Ackerly, 1964).

Eslinger et al (1992) suggested the im pairm ent became obvious due to the increasing discrepancy between the burgeoning dem ands of adolescent development, and altered m aturation of the frontal lobe neu ral an d cognitive system s. At a cognitive level, the patient failed to acquire the executive an d self-regulatory processes associated with the frontal lobes. This became ap p aren t in early adolescence at a time when m aturation of such processes is critical to psychological developm ent (cf prim ate model of development; Goldman, 1971). Furtherm ore, a t the neurobiological level, early frontal lobe ablation h a s been associated with subsequent anatom ical changes in proximal a n d distal areas (Goldman and Galkin, 1978; Kolb and Gibb, 1990). This may have occurred in the case described.

Similarly, norm al child studies have indicated th a t discrete "growth spurts" m ay occur in each frontal lobe throughout childhood and adolescence (Thatcher, 1991; and see discussion above). The Eslinger et al case's lesion occurred a t age 7- an im pedim ent in physiological m aturation would th u s have been expected. However, im pairm ents did not become ap p aren t until three to five years later. It could be argued this is when the development of the cognitive a n d neurobiological system associated with the dam aged area should

5.3. Summary and Conclusions.

The evidence presented in this chapter suggests developm ent of the frontal lobes to be far from linear, with distinct stages being observable both anatom ically and cognitively. The evidence

su rro u n d in g th e consequences of frontal lobe dam age su stain ed in childhood is on occasion contradictory. The thesis of EsUnger et al (1992) would, however, appear to offer one solution to th is

contradiction.

Chapter 6:

Functions of the