Nuremberg,
Germany, 1828: A savage and mysterious adolescent boy named Kaspar
Hauser appears in the city. He has little knowledge of language, and
both his gait and behavior are reminiscent of a young child [1]. Very
likely, he was imprisoned throughout his childhood, and raised under
conditions of extreme deprivation. Kaspar Hauser becomes a famous
attraction of the 19th century, scientists and philosophers
worldwide study his behavior attempting to uncover his origin. Some
think that he is the prince of Baden, who was abducted from his cradle;
others claim he is an imposter.
Whatever the truth of Hauser’s
life, his case is the oldest documented and most famous case of severe
childhood deprivation. Extreme hospitalism, or neglect-mediated failure
of development, is thus also called “Kaspar-Hauser Syndrome”. This
malady is characterized by retarded physical development,
perceptual-motor skills and language as well as extreme anxiety. It is
caused by sensory deprivation and lack of social contact or abuse during
early childhood.
LACK OF SENSORY INPUT IMPAIRS NEURODEVELOPMENT
Another genre of child neglect is the wolf child
or feral child, who has lived isolated from human contact and has no
experience of human behavior and lan
guage. The most famous example is
Mowgly from the fictional story The Jungle Book. The difference
between Kaspar-Hauser Syndrome children and feral children can be seen
in their behaviour. Feral children behave like the animals with which
they lived (e.g.wolfes), because they have learned their behaviour
instead of human behaviour. Severely deprived Children do not learn any
behaviour and are thus even more retarded in their perceptual-motor
skills and development.
 |
| Abnormal brain development following sensory neglect in early
childhood. Left: CT-scan of a healthy three-year old with an average
head size. Right: CT-scan of a three-year old child suffering from
severe sensory-deprivation neglect; this child’s brain is significantly
smaller and has enlarged ventricles and cortical atrophy. |
Studies of child neglect
As
it would be brutal to deprive children of care for the sake of science,
most studies rely on case reports of severely neglected children [2].
Thereby, often, the child's medical and social history is unknown. As in
the case of Kaspar Hauser, scientists usually do not know the exact
form of neglect, or whether neurological defects are a direct
consequence. Many studies on hospitalism are based on children raised in
badly-run orphanages [3]. Children who were adopted from Romanian
orphanages in the early 1990s were often considered to be extremely
neglected. Studies with them show that early life nurturing is critical
for neurodevelopment. If nurturing is absent for the first three years
of life before adoption into a social environment, newly made positive
experiences may not be sufficient to overcome the malorganization of the
neural system.
Principles of neurodevelopment
To
understand how deprivation impairs behavioral and cognitive capacities,
we need to first understand the principles of neurodevelopment: At
birth most neurons are already present, yet they have to organize into
functional systems. Thereby activation of recurrent patterns appears to
be an important factor. Neurons that are not sufficiently activated
undergo apoptosis in a ‘use it or lose it’ manner. The sculpting and
refinement of neural connections is resolved by dendrite and axon
sprouting, followed by synaptogenesis. The latter process is tightly
regulated by growth factors and adhesion molecules, whose expression is
regulated by environmental cues mediated by the senses.
The brain
develops in a sequential fashion; different areas form, organize, and
become fully functional at different times during childhood. There are
thus different sensitive periods for each brain area and neuronal
function. Disruption of critical cues can alter the developmental
processes and lead to diminished capabilities in the neural system for a
given sensory modality. Disruption of critical neurodevelopmental cues
can result from (1) lack of sensory experience during sensitive periods
(e.g., neglect) or (2) abnormal patterns of necessary cues due to
extremes of experience (e.g., abuse).
Clinical impacts of child neglect
Disturbed
neurodevelopment results in defects in language, motor delays,
impulsivity, disorganized attachment, dysphoria, attention deficits, and
hyperactivity. Furthermore neglected children have a reduced
frontal-occipital circumference, which is an estimate of brain size in
young children. Furthermore, CT scans from neglected children show
enlarged ventricles or cortical atrophy [4]. MRI studies with maltreated
children also demonstrate decreased metabolic activity in a number of
brain areas [5].
EARLY LIFE NURTURING IS CRITICAL FOR NEURODEVELOPMENT
The severity of neurological issues increases
with the time children spend in an adverse environment: The earlier and
more pervasive the neglect, the more indelible the deficits. After the
children are removed from the neglectful environment, the degree of
recovery is inversely proportional to age in which the child was removed
from the neglecting caregivers [4].
We learn from these studies
that neurodevelopment depends on both nature and nurture. Many functions
of the brain result from a complex interplay between genetic potential
and appropriately timed experiences. Child neglect - defined as the
absence of input in critical periods of development - leads to
abnormalities in cognitive, emotional, behavioral, and social
functioning. Healthy neurodevelopment depends upon attentive nurturing
during infancy.
To make sure stories like Kaspar Hauser’s and
similar horrible stories of child neglect don't happen again, social
services provide help for families where neglect is suspected. If
parents are unable to meet their children's needs then professionals
intervene to safeguard the child's welfare. As stimulation of a child's
senses in the early infancy is so important, it is neccessary to act
early if child neglect or abuse is suspected. No issue cries out for a
more immediate and all-encompassing response than ensuring the safety
and well-being of our children – our hope for the future.
[1] Feuerbach, 1835 (Klett, 1963)
[2] Spitz, Psychoanal Study Child, 1945
[3] Barth Spiegel, 1990
[4] Perry, Brain and Mind, 2002
[5] Chughani et al, Neuroimage, 2001
by Claudia Willmes, PhD alumni AG Eickholt / AG Schmitz
This article originally appeared in CNS Volume 7, Issue 3, Nature vs Nurture
