A significant number of infants are at risk of neurodevelopmental disorders as a result of a difficult pregnancy due to various health problems of the mother or the fetus, or as a result of complications during delivery or the days that follow. Uteroplacental insufficiency is part of these perinatal conditions that could cause hypoxic-ischemic brain damage and thus could interfere with child development. Whatever the perinatal pathology responsible for hypoxic ischemic phenomena might be, the arising developmental disorders can be grouped into two broad categories according to their severity and time of emergence:
- severe impairments, usually appearing early: cerebral palsy, sensory impairments, mental deficiency, epilepsy
- minor and moderate impairments, generally appearing later: language or motor coordination difficulties, visual-spatial difficulties, attention deficit disorders, behavioural disorders
Severe disorders, which are usually of low prevalence, may generally be identified within the first two years of life. Moderate and minor disorders are far more prevalent; they generally become apparent in the preschool or primary school years as performance requirements gradually increase. Indeed, these requirements solicit higher brain functions for which the maturation and organization occur at a later stage.
In current follow-up practices for children in this group, the clinician is often uncertain, passively waiting, in the absence of reliable clue to late outcome, particularly when it comes to developmental disorders that appear later on. Developmental evaluations and functional assessments allow to confirm or deny the presence of specific skills depending on the age of the child. However, this approach has a low predictive value during early childhood for future problems. To overcome this methodological pitfall, we suggest the use of a neurological assessment as it allows the detection of signs which are of both early emergence and persistence. Neurological signs become markers that allow the establishment of a link between perinatal events and future developmental challenges. They also help to plan targeted early interventions, i.e active anticipation rather than late identification.
In the context of the PIAF study, and in a broader sense of any other follow-up of children at risk, we recommend using the neurological evaluation in combination with a developmental assessment such as the Bayley Scales of Infant Development – III . Such an approach permit identification not only of children with severe developmental impairments but also those whose neurocranial markers indicate high risk of minor or moderate disorders occurring later.
Recent research results show evidence that minor or moderate neurocranial signs provide a link between perinatal events and future developmental disabilities. Depending on the child’s profile and on follow-up objectives, a functional assessment may complement this first evaluation process; the Gross Motor Function Classification System, the Manual Abilities Classification System or even the MIF-môme or the PEDI are the most frequently used functional measures. This training module is mainly focused on neurological assessment at term age, and up to 6 years.
Diversity of clinical exploration methods of brain function
A large number of neurological assessment methods have been previously proposed. Some of these methods focus on neurobehavioral aspects, mainly documenting the adaptability and self-regulatory capacity of the infant. Others are based on a meticulous analysis of the child’s motor skills. Such methods can be restricted by a specific age stratum or by allowing for only a partial analysis of brain function. Consequently, in the context of a follow-up, switching to a different method becomes inevitable, and such a switch is likely to cause difficulties in interpreting developmental trajectories.
The method that we propose, the Amiel-Tison and Gosselin neurological assessment from birth to 6 years, offers a fairly broad analysis of brain functions from the neonatal period until the age of 6 years. Such an approach ensures a methodological continuity throughout follow-up and thus facilitates interpretation based on repeated evaluations. This assessment focuses on the exploration of muscle tone, both passive and active (especially in the assessment around the age of term), allowing to detect the emergence of spasticity or others tone abnormalities. It also includes an assessment of cranial growth based not only on the measurement of head circumference but also on the examination of cranial sutures. Therefore, this is neither just a physical examination nor just a developmental assessment.
Historical aspects of the method
This 0-6 Instrument has an history. Based initially on the framework developed by André Thomas concerning muscle tone and on the method for analytical evaluation of passive muscle tone in limbs developed by his successors (Stamback and Ajuriaguerra, 1958 St. Anne Dargassies, 1982), it has evolved over the years. Successive steps in the elaboration of the assessment presented here can be summarized as follows:
- Identifying different components of axial tone in normal and abnormal development (Amiel-Tison, 1974; Amiel-Tison, et al, 1977).
- Didactic description of each selected item and interpretation of results in terms of neurological maturation within the first year of life, including a form to gather monthly data of young children (Amiel-Tison, 1976, Amiel- Tison and Grenier, 1980, 1985).
- Conceptual distinction between permanent neurological abnormalities associated with brain damage and disabilities evolving with maturation (Amiel-Tison and Stewart, 1989).
- Interpretation of normal and abnormal results (Amiel-Tison, 1999) in light of the anatomic and physiological correlates presented by Sarnat (1984, 1989, 2003).
- Awareness of pitfalls related to deformations and muscle shortenings arising from abnormal postures; prevention of those deformations is important for the child’s future functional skills, but also for the accuracy of the neurological assessment (Grenier, 1995).
- Integration of cranial data as an indispensable component of the systematic neurological assessment (Amiel-Tison and Stewart, 1995; Amiel-Tison et al, 2002).
- Description of the specific procedures for administration and scoring (Amiel-Tison and Stewart, 1989; Amiel-Tison and Gosselin, 1998) applicable to the evaluation both at 40 weeks of gestation (term) (Amiel-Tison, 2002; Gosselin et al., 2005) and up to 6 years of age (Amiel-Tison and Gosselin, 2007; Amiel-Tison and Gosselin, 2011), thus avoiding any methodological rupture in the course of follow-up of young children cohorts.
- Proposal for a classification based on absence or presence of clusters of signs, reflecting the complete spectrum of neuromotor abnormalities at this age (Gosselin et al., 2002; Amiel-Tison and Gosselin, in press) .
- Identification of neurocranial clues between perinatal causes and late neurocognitive dysfunctions (Amiel-Tison et al, 1996; Amiel-Tison and Stewart, 1995; Couture, 2005; Gosselin et al., 2002, 2006, Simard et al, 2010,2011; Amiel-Tison and Gosselin, in press).
The proposed evaluation is therefore the result of successive stages in the elaboration of a fairly simple clinical assessment, i.e an assessment wich cannot be reduced much further. In its current form, it is easy to integrate into daily practice.
One method, three instruments
Three instruments were developed using the same conceptual framework in order to assess children in the following three periods, each of which requires an evaluation method appropriate to the maturation stage. This methodological continuity is highly valuable in follow-up studies.
Maturative waves, mainly upward during preterm period and then downward from term with an overlap around 40 SA, enable us to identify three important periods which correspond to three distinct instruments:
- Amiel-Tison maturation assessment in preterm infants (area 1 on figure) : The first version dates from 1968 (Amiel-Tison, 1968). Thereafter, it was gradually simplified into a single 10-item chart, including active muscle tone, passive muscle tone and primary reflexes (Amiel-Tison, 2001, 2005). This form offers maturational profiles every two weeks, taking into account the vertical alignment of all responses. This assessment is not always feasible in the newborn intensive care unit, but it can be done later at 40 weeks corrected age.
- Amiel-Tison neurological assessment at term (area 2 on figure) : The period of the term is known as a period of ” physiological spasticity” (Sarnat, 1984), during which the lower motor control system is strongly expressed (quadriflexion of limbs, vigorous primary reflexes); but for the clinician, it is mainly a period where the upper motor control system is starting to control antigravity forces through the action of its body axis flexors. To demonstrate this, the “raise-to-sit” and “back-to-lying” maneuver is essential to analyze the perfect balance of active head movement forward and backward in response to the manipulation of the trunk by the examiner. A scoring system is used with scores 0, 1 and 2 for each observation or maneuver (Amiel-Tison, 2002, 2005). At the end of this basic examination, it is possible either to confirm the neurological optimality or highlight a cluster of abnormalities in the newborn at term or in a preterm infant between 38 and 42 weeks corrected age.
- Amiel-Tison and Gosselin Neurological assessment from 0 to 6 years (area 3 on figure) : This assessment is at the core of our method of neurological assessment and lies in continuity with the previous two. From 0 to 2 years, the maturation speed of the upper motor control system is so fast that the normal values of responses vary by 3-month periods during the first year (progressive relaxation) and then more slowly, every 6 months during the second year. From 2 to 6 years, an annual review is sufficient.
An effort was made to ensure consistency between the three instruments, same rating system and same approach for the analysis of results. For some items, the expected response is the same regardless of the age of the child being evaluated; for others, the criteria of normality and abnormality differ during the first 2 years of life to reflect the rapid changes associated with brain maturation. Additionally, although several items are similar for all three instruments, some neuromotor aspects are specific to a particular one: for example, crossed extension reflex is only useful for the preterm period; and postural reactions such as the parachute are not sought in the first 6 months because they are not yet present.