Detecting developmental delay

Practice nurses see babies and young children on numerous occasions throughout their early childhood, placing them in a prime position to recognise when something is not quite 'right'. But when should you reassure and when should you refer?

Developmental delay means the child is not developing at the expected rate, and this can have significance for their physical, educational and social needs now and in the future.

Children develop their social, speech and motor skills at different rates — the range of normal is wide. A child would generally be considered to have developmental delay if they were amongst the last 2% of their age group to reach a particular developmental milestone.

Developmental delay is a symptom, not a diagnosis. It can have a myriad of causes — examples are given in Table 1. Some children with developmental delay will simply be on the late end of normal and will have no underlying problem or long-term developmental issues — but the later they are, the more chance there is of a significant problem.

Developmental delay can affect one area alone, several or all areas of development. Children who are delayed in reaching all their milestones are said to have global developmental delay.

HOW DO WE DETECT DEVELOPMENTAL DELAY?

We detect it in four ways:

1. By regularly reviewing children in whom a problem is already expected. Examples might include babies with Down's syndrome, who show developmental delay in several areas. This is to enable targeted support to be offered to those most in need, and these children are usually under specialist paediatric review.

2. Through a child health surveillance programme, largely led by health visitors, which checks all children at five key developmental stages and checks to see that they have attained certain milestones. (Box 1)

3. By responding to parents' or school concerns and assessing children who seem to be deviating from 'normal'.

4. Through observation, in the surgery, of something unusual or concerning that nobody else has yet noticed.

The role of the practice nurse comes in mainly with the last two, which perhaps seem most difficult. However, lots of children pass through our surgeries every day. We see them for immunisations, minor injuries, minor and major ailments. We soon build up a picture of the 'typical' child. If you back this up with an understanding of developmental paediatrics you are well prepared to routinely assess children against normal development whenever you see them.

Key skills

The key skills for detecting and assessing developmental delay are

• Appropriate suspicion
• Appropriate knowledge
• Understanding and support

The practice nurse therefore needs:

• A working grasp of what normal development is
• A 'feel' for abnormal development 'patterns'
• Awarenesss of when to refer
• Ability to reassure when appropriate

WHAT IS CHILD DEVELOPMENT?

Child development is the interaction of the child's genetic potential with their environment.

AREAS OF DEVELOPMENT

Child development can be classified into several separate areas:

• Hearing, speech and language
• Vision
• Motor skills
• Social behaviour

Speech and language

Early speech development is dependent upon hearing, so these two go together. Later, language development is also a social skill and so is related to conditions that affect social skills, such as autism.

Most parents can tell you when their baby said their first word. Babbling usually progresses to first attempted words by 9-12 months of age, and most children have said their first clear words by 18 months. A child who does not say their first word by 24 months is in the latest 2% for speech development. This puts them in a group of children who may still be normal, but who may have an underlying reason for their speech delay.

Causes of speech delay include:

• Familial tendency to speech delay
• Hearing impairment
• Social developmental disorders such as autism
• Abuse: speech delay can occur in those who are not being spoken to and nurtured. Emotional abuse usually accompanies physical or sexual abuse, but can also occur alone
• Poor parenting, lack of social stimulation of the child
• Psychological conditions causing regression of language skills: Stress, trauma, abuse, prolonged hospitalisation, elective mutism

Children with significant speech delay should be referred for developmental assessment by a paediatrician. Early intervention with speech and other therapies can make a difference.

Hearing

It's important to consider hearing when assessing language, learning and social skills. Sensorineural deafness occurs in 1 in 1000 children, while conductive hearing loss (due to blockage in the ears, e.g. wax, or 'glue ear') is common. All babies now have their hearing tested at birth, but hearing loss can develop after birth, either due to inherited or acquired conditions.

Hearing loss is more likely in children with Down's syndrome and other congenital disorders that affect the shape of the face and ear canal, such as William's and Turner's syndromes. These children are particularly prone to chronic glue ear. Some children show an abnormal response to hearing — suggesting pain or distress. This is suggestive of a more generalised disorder such as autism.

Vision

Vision develops gradually in children. A newborn baby should be able to fix their gaze on their mother's face. By the time they are 6-8 weeks old babies should display social smiling, which is an indication that they can see. Serious causes of visual defects in babies include retinoblastoma, cataract and glaucoma. Early detection is essential as some of these conditions are correctable if treated early, whereas if left too late normal visual development can fail to occur. Impaired vision affects all development.

Motor development

Early delay in motor development shows itself as floppiness, or asymmetry of limb movement or posture. There is a wide range of normal, particularly at birth when premature babies are floppier and babies who have had the head tilted back in utero tend to have floppier neck muscles. Floppiness may be associated with global delay or with specific syndromes. Examples include Down's syndrome (babies are characteristically floppy), and cerebral palsy (babies are initially floppy although limb stiffness and posturing may develop later.)

Disturbance of gait (walking style) can signify cerebral palsy or brain disorders including congenital abnormalities of the cerebellum (the part of the brain that organizes balance) and brain tumour.

A particularly worrying sign is regression of motor skills — loss of previously acquired abilities. This is seen, for instance, in Duchenne muscular dystrophy, when children (usually boys) lose the ability to get up from sitting and, later, to walk, as progressive muscle weakness starts to become apparent around the age of 3-4 years.

Muscle wasting with weakness is a worrying sign. It is seen in Duchenne muscular dystrophy, where the thigh muscles may show wasting although the calves initially look well developed. Polio, a flu-like viral illness, which can attack nerve cells in the spine, was once a common worldwide cause of loss of motor function with wasting.

Walking

By 12 months about half of children are starting to walk. Less than 1% emulate the Russian Tsar, Peter the Great (1672 — 1725) who is said to have walked at 8 months. Over 90% walk by 15 months, and by 18 months those children still not walking are by definition, in the bottom 2%. Amongst this group neuromuscular abnormalities with long-term consequences are more likely. This includes spina bifida and Duchenne muscular dystrophy. Children with spina bifida do not always have permanent impairment — in many cases despite late development they go on to have normal motor function.

Cerebral Palsy

Cerebral palsy (CP) deserves a separate mention. It is caused by damage — probably before birth — to the motor cortex, and it leads to a non-progressive motor defect. However, although the damage doesn't change, the signs of CP do change as the baby gets older and muscles fail to work as they should. Posture and movement are both affected, but mild cases may not show until children are over a year old. Most children have predominant muscle stiffness, but some remain floppy or develop abnormal movements. CP does not involve learning difficulties although these are often associated with CP when there has been damage before or at birth. However, many children with CP are socially intellectually unimpaired.

Social skills

Disorders of socialisation, play and communication can be difficult to detect. Parents usually notice first, although problems are sometimes not apparent until well into school life. Babies' social skills begin with smiling and, later, language so it is difficult to separate social skills from other developmental areas completely.

• Causes of delayed or abnormal social development include:
• Sensory impairment
• Natural shyness
• Autistic spectrum disorder
• Emotional and/or physical abuse
• Unreasonable parental expectations
• Global developmental delay
• Attention Deficit Hyperactivity Disorder (ADHD)

Later presenting conditions

• Learning difficulties
• Psychiatric illness (particularly in the early teens)
• Milder forms of autistic spectrum disorder (previously Asberger's syndrome)
• Behavioural problems and conduct disorder
• Abuse
• Bullying (peer abuse)
• Stress, post traumatic stress disorder

Autistic spectrum disorder

and ADHD

Diagnoses of autistic spectrum disorder (ASD) are increasing. ASD ranges from classical ('Kanner') autism (which causes profound disability and incidence of which has not increased in frequency) to various degrees of autistic spectrum disorder (which overlaps with what was formerly called Asperger's syndrome, now also referred to as ASD as there is no clear separation between the two.) Children with autism commonly show speech delay and in severe cases remain non-verbal throughout their lives.

ASD, particularly in higher functioning children, is difficult to diagnose and detailed assessment is required. The child's behaviour must be assessed in every situation (i.e. at home and at school) and educational psychologists may be involved. There are many books written on the perceptions that young people with autism have. These can include abnormal sensory experiences (such as pain on hearing music), obsessive behaviours (such as lining up play items or food), poor eye contact, difficulty making friends and lack of empathy. Autistic savants — children with a particularly remarkable skill in one area — are rare.

ADHD usually presents in school age children. It can affect socialisation as children have poor attention span and concentration, and a lack of impulse control, but it does not affect language and does not impair sensation.

ASSESSING THE CHILD: WHERE TO START?

The practice nurse faced by a child whose parents have concerns about development, or who herself feels that development may be abnormal, needs a thorough and organised approach to assessment, in order to determine which children need to be referred, and where to. Box 2 suggests important elements in the assessment.

WHAT ARE YOU LOOKING FOR?

Some would say it is difficult to say what you are looking for until you find it, because you are looking for abnormal deviations from the normal pattern. (Some deviations from the normal pattern are themselves normal, e.g. not all children crawl before they walk.)

However, some patterns are clearly abnormal — for example the child who makes no attempt at communication and avoids eye contact is not in a normal phase of development.

Abnormal patterns which should raise concern

• Any area: Regression
• Motor: Asymmetry, gait disturbance, scissoring, ballerina gait, posturing, hand flapping, tiptoe walking
• Social: Ritual behaviours, self-harm, avoidance of eye contact
• Visual: Squint, nystagmus, random eye movements, photophobia
• Hearing: Distress at normal sounds

Regression

This is when development moves backwards and skills are lost. It is always important and needs urgent referral.

Causes of global regression include

• Abuse
• Space occupying lesions
• Autism/autistic spectrum disorder
• Neuro-degenerative conditions e.g Rett's syndrome (these are rare).

Causes of motor regression include

• Muscular dystrophy (usually presents aged 3—4 years)
• Neuromuscular and muscular disorders
• Loss of vision

N.B. Cerebral palsy is not an evolving condition so it does not cause regression

Causes of language regression

• Neurological or hearing disorders
• Autism
• Elective mutism
• Abuse

WHEN TO REASSURE AND WHEN TO REFER

When to refer often seems straighforward — almost certainly you would have referred the conditions below before reading this article.

Refer for urgent paediatric assessment in the case of

• Severe concerns from health visitor or parents
• Dysmorphism with delay
• Severe delay in one area
• Milder but global delay
• Regression in any area
• Abnormal patterns such as motor asymmetry or gait disturbance, posturing or social withdrawal
• Gut feeling

More difficult is knowing when to reassure. To do this you need to develop confidence in your own assessments and thus a trust in your gut feelings. This comes with time and experience.

In the meantime, if in doubt, ask a colleague, and learn from each and every assessment you make of the development of every child you see. It is better to over refer than to miss a serious case.

SOME LATE PRESENTING CONDITIONS

Most major developmental conditions in children present early when they are young — so to a certain extent the older the child the less likely you are to find, for the first time, something significantly wrong.

There are however some late presenting conditions. Examples include

• Dyslexia
• Dyspraxia (clumsiness, poor motor skills)
• ADHD
• ASD/Asperger's syndrome
• Muscular dystrophies (sometimes)
• Psychiatric conditions
• Behavioural conditions
• Abuse (any age)

Genetic conditions such as Turner's syndrome can cause learning difficulties but often present late as delayed or absent puberty

• Growth disorders

A FEW FACTS

In the majority of developmentally delayed children, there is no clear diagnosis or cause. Some of the most disabled children have no diagnosis.

Parents generally receive little financial help. The stress on families can be enormous. Respite care is often offered and not wanted. Extra help at home is often wanted but not offered.

Children with special needs are more likely to be abused.

They are less likely to live in a two-parent household

Children with special educational needs in mainstream schools should be offered extra support to fulfil their potential, but this comes out of the regular school budget so they could often benefit from more.

WHO CAN HELP?

Some areas of community/developmental paediatrics are receiving ever-increasing levels of referral. Many now limit the cases they will review to those meeting fixed criteria. Other children see general paediatricians.

Most developmental problems occurring after school age fall into the remit of education rather than health. Unfortunately, there is an area in between education and health where a gap of funding and support can occur, and parents may feel the system offers their child very little in terms of equipment and care.

SUMMARY

Detecting developmental delay in any care offers the child a better chance of fulfilling their potential. Not all issues will be raised by parents. Practice nurses see children every day. Particularly, they see children in immunisation cohorts on a regular basis — babies, pre-schoolers and young teens. They are well placed to spot the abnormal, the different and the frankly worrying and should not be afraid to raise concerns.