• Neurodevelopmental outcome
  
• Hearing impairment (deafness)
  
• Visual impairment

Introduction

Although advances in neonatal–perinatal care have dramatically improved the survival of very premature babies, they remain at high risk for adverse neurodevelopmental outcomes and therefore a carefully planned follow-up of these babies has now become an essential part of the neonatal care service provision with an aim to help in:

• Early identification of major problems such as cerebral palsy, developmental delay, major hearing or visual impairment. This in turn should facilitate further diagnostic test, assessment, and involvement of other relevant professionals and agencies.
  
• Screening for other problems (e.g. squint, speech delay, growth failure) and implementation of early remedial measures.
  
• Maintenance of optimal health in order to achieve the utmost potential for growth and development.
  
• Support to parents/caregivers regarding the child’s problems, prognosis and the need for consultation with other specialists (such as ophthalmologists, paediatric surgeon, orthopaedic surgeon, neurosurgeon, neurologist, psychologist and clinical geneticist) and therapists (such as physiotherapists, speech and language therapists and occupational therapists).

Neurodevelopmental Outcome

A high proportion of at-risk infants develop transient neurologic abnormalities including abnormalities of muscle tone such as hypotonia or hypertonia, hyperexcitability, poor postural control, feeding difficulties and persistence of primitive reflexes. Although most of these transient abnormalities may resolve by the second year of life, it might also be an indicator of later neurological dysfunction and such babies require close and longer-term neurodevelopmental surveillance. Further problems could emerge during the school age years, such as specific learning difficulties, behavioural problems and attention deficit hyperactivity disorder (ADHD), even in presence of normal intelligence.

Major neurologic disabilities include the following:

• moderate to severe cerebral palsy
  
• blindness in both eyes (registered blind)
  
• severe deafness (requiring hearing aid)
  
• significant delay in cognitive development
  
• intractable seizures (epilepsy).

Cerebral Palsy

The term cerebral palsy (CP) refers to a loop of non-progressive, but often changing, motor impairment syndromes secondary to lesions of the developing brain and includes three components:

• abnormalities of tone, reflexes, coordination, and movements
  
• delay in motor milestones
  
• aberration in primitive reflexes (retention> 6 months).

CP is classified by the number of limbs involved and the severity of the condition (see Box 23.1).

Another way to classify CP is to describe it as ‘non-disabling’ or ‘disabling’. A functional measure, the Gross Motor Function Classification System (GMFCS) has been developed to systematically evaluate functional skill in different motor activities such as sitting, walking, jumping and running, and this seems to provide a more stable measure of functional ability over time.

CP occurs more frequently among babies with extremely low birthweight (LBW) as compared to controls with normal birthweight. Recognized risk factors include abnormal cranial ultrasound findings, particularly large intraventricular/periventricular haemorrhage (PV-IVH) and periventricular leukomalacia (PVL), severe respiratory distress requiring prolonged ventilation, refractory hypotension, postnatal corticosteroid therapy and multiple births. In contrast, among term infants, in many cases no cause can be found despite extensive investigation.

As in most infants, neurological impairment may be transient; the diagnosis of CP should be delayed until a time when motor development has been established, which is usually 3–5 years of age unless the abnormalities are severe and obvious. Similarly, assessment of cognitive function may not be accurate until 3 years of age.

Clinical Risk Factors for Adverse Neurodevelopmental Outcomes

Certain perinatal and neonatal conditions which are recognized risk factors for adverse neurodevelopmental outcome, are listed in Box 23.2 and Box 23.3.

Structured Plan for Follow-Up Assessment

• Listening to the parents/caregivers’ concerns.
  
• Regular anthropometric measurements: weight, length, and head circumference.
  
• Review of systems particularly for any health problem including feeding.
  
• Assessment of vision and hearing.
  
• Neurological/neurodevelopmental assessment:

Most studies these days use BSID-III, which includes a Mental Developmental Index (MDI), a Psychomotor Development Index (PDI), and a Behaviour Rating Scale (BRS) to assess developmental outcomes of high-risk infants in the first 3 years of life with high reliability. Bayley scores of 100 represent the mean ± standard deviation of population of normal infants born at term. A score of less than 70 (two standard deviations below the mean) is used as evidence of significant developmental delay.

Hearing Impairment (Deafness)

The importance of early diagnosis in hearing-impaired children is obvious, as appropriate sound amplification and the provision of specialized educational facilities will enable the deaf child to realize his/her maximal potential. Speech in deaf children is much better if hearing aids are fitted in the first 6 months of life.

Hearing impairment takes one of the following forms:

• Conductive. This involves abnormalities of the external auditory meatus, the tympanic membrane or the ossicles within the middle ear. This can rarely be congenital if the meatus has not yet canalized; much more commonly it is due to infection or serous exudate within the middle ear.
  
• Sensorineural. Abnormalities or damage to the cochlea or brainstem nuclei cause ‘nerve’ deafness.
  
• Mixed. Not uncommonly children with sensorineural deafness may also develop infection, which may further impair hearing as a result of conductive loss.

Screening for Hearing in the Neonatal Period

Two methods for screening are used: the otoacoustic emissions (OAE) and auditory brainstem response (ABR) tests. All newborns in the UK have OAE testing and those at high risk will go on to have an automated ABR test.

Otoacoustic Emissions

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