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Management of developmental speech and language disorders. Part 2: acquired conditions
  1. Anne O'Hare
  1. Correspondence to Professor Anne O'Hare, Child Life and Health, School of Clinical Sciences, University of Edinburgh, 20 Sylvan Place, Edinburgh EH9 1UW, UK; aohare{at}ed.ac.uk

Abstract

Many children who present with these acquired impairments of communication have a clear preceding event such as an acquired brain injury from a road traffic accident. Children often respond differently in this situation to adult presentations. They may have a period of mutism when the prognosis might look poor and yet they subsequently make rapid progress and recover speech. They have greater potential for neural plasticity and language recovery, although they often have persisting difficulties in oral and written language. Alternatively, there may be a presentation with a paroxysmal event such as a seizure or a period of depressed consciousness, and the unusual behaviour that may accompany dysphasia and dysarthria may be misinterpreted in the child, whereas for the adult with the more common ‘stroke-like’ presentation, it would be immediately considered. Rarely the aphasia/dysphasia may itself be the paroxysmal event where actually recognising that the child's disrupted communication is the basis of any observed behaviours can be the greater challenge.

  • Neurodevelopment
  • Neurodisability

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The speech production systems are as relevant for acquired disorders of speech as they are for developmental disorders (refer to Part 1: management of speech and language disorders. Part 1: developmental conditions). The phonological component incorporates cognitive and linguistic elements, and so it can be difficult, depending on the mechanism and distribution of the injury, to separate out the speech production from aphasic components. This means that while a child with acquired brain injury may appear to have more impact on the speech production system in dysarthria or, conversely, spoken language with dysphasia or aphasia, where language appears absent, there are frequently elements of the two. However, for the purposes of clarity, they are discussed below separately as either dysarthria or dysphasia according to which one predominates in the clinical picture.

Dysarthria

Dysarthria is a long-term and severe speech disorder of neuromuscular control of speech sound production and signals bilateral disruption of neural pathways.1 ,2 Three of the most frequent paediatric situations in which it is encountered among children affected by serious brain insults are cerebral palsy (discussed here under acquired conditions, recognising that some forms arise from developmental brain anomalies), where it effects around one-third,3 survivors of moderate-to-severe traumatic brain injury where it affects 20%4 and following resection of neoplasms in the posterior fossa where again it involves around one third.5

Although the articulatory misplacement is the primary mechanism impairing intelligibility in dysarthria, there are contributions from a wide range of difficulties that compromise the strength of the articulation and speed, maintenance of power, tone, phonation, resonance and prosody, that is, the suprasegmental aspects of speech that convey intonation and emotion. Speech can sound slurred and effortful. There may be associated dysphagia, and the clinical assessment of the integrity of the airway protection is crucial and assumes great importance as it is more frequently compromised in acquired dysarthria than in rare developmental syndromic dysarthrias (refer to Part 1). A framework of the clinical features in the different forms of dysarthria are shown in table 1 (figure 1). An onset dysarthria, when it occurs in a previously well child, requires referral to paediatric neurology as soon as possible because impairment of the airway integrity can be rapidly progressive secondary to some neurometabolic demyelinating motor neuron and brain stem tumour aetiologies.

Table 1

A framework of the clinical features in the different forms of dysarthria

Figure 1

Single T2 axial image showing high signal in the left cerebellar hemisphere secondary to viral cerebellitis.

Traumatic brain injury

In the acute phase following paediatric traumatic brain injury, there are often accompanying oromotor deficits with facial nerve dysfunction affecting buccal and labial movement, and hypoglossal nerve dysfunction with reduced tongue strength and coordination. A smaller number of children also display trigeminal nerve impairment affecting jaw movements and vagus nerve involvement that impairs velopharyngeal function. Ten per cent of children, in a series of those sustaining moderate-to-severe traumatic brain injuries, had accompanying dysphagia.4 Childhood dysarthria appears to differ from the acquired form in adults in that it primarily follows bilateral and not unilateral damage to the neural pathways. Liegeois and Morgan1 describes how lesions are seen in the white matter along the corticobulbar and spinal tracts (incorporating corona radiata, central semiovale, internal capsule), midbrain, grey matter lesions within the perisylvian and perirolandic cortices, basal ganglia of putamen, caudate nucleus, thalamus and cerebellum. The best predictor of dysarthria was involvement of the dorsal corticobulbar tract.

Dysarthria and posterior fossa syndrome

Following resection of cerebellar tumours, 8% of children develop the classical picture of ‘posterior fossa syndrome’, which is characterised by cerebellar dysfunction, oculomotor dyspraxia, oral motor dyspraxia, emotional lability and mutism. Up to a third of children overall will experience dysarthria in the acute postoperative phase. Recovering speech shows deficits that include distorted vowels, slow rate, voice tremor and monopitch, and these features differ from those found in adult onset ataxic dysarthria.6 While the postoperative mutism is associated with a poorer long-term prognosis with long-term dysarthria, even non-mute children experience long-term speech deficits of mild dysarthria affecting consonant production, pitch and rate.7

Rare causes of acquired dysarthria including neurometabolic disorders

Herpes virus infections of the brain have a predilection for the temporal lobes and can have a devastating encephalitic presentation. However, rarely, the neurological manifestations in childhood are those of an opercular syndrome with facial palsy, dysarthria and dysphasia. These conditions constitute a medical emergency requiring urgent treatment with high-dose intravenous acyclovir, and so the second, slightly more unusual, presentation needs to be recognised as a herpes virus brain infection.8

There is a small number of case reports in which dysarthria is associated with metabolic disorder.1 In contrast to adult practice, dysarthria resulting from basal ganglia dysfunction is very rare, but it is seen in juvenile Huntington's chorea and pantothenate kinase associated neurodegeneration. Dysarthria can result from white matter impairment across the cerebral hemispheres in leukodystrophies and, with disease of the cerebellum and basal ganglia, in gangliosidosis and Wilson's disease.

Onset dysarthria can occur in the context of some extremely rare diseases of childhood, and timely diagnosis is imperative as there are some indications that treatments such as riboflavin may slow down the degenerative process in some of the rare motor neuron diseases of childhood, for example, Brown–Vialetto–Van Laere syndrome and Fazio–Londe syndrome. Timely diagnosis is also important because there can be rapid progression of wider neurological features after the disease onset, for example, Fazio–Londe syndrome can manifest with onset dysarthria, and the child may show rapid progression with stridor, respiratory distress, ptosis and facial and limb weakness over the ensuing 16–18-month period. The scope of investigation including neurophysiology and electromyography, looking for anterior horn cell involvement in the cranial nerve nuclei and spinal cord, is outside the scope of this review and requires management in paediatric neurology.9

Aphasia/dysphasia

Aphasia/dysphasia is frequently comorbid with dysarthria and associated with mutism in the acute phase. It may be followed by long-term speech production and language impairments even though children show far greater recovery from acquired aphasia than adults. There can be relative preservation of comprehension in the acute phase and subsequent rapid improvement in speech and expressive language. Table 2 gives examples of acute neurological conditions associated with aphasia/dysphasia. The majority of children have a non-fluent dysphasia, which can be prefaced by mutism, although around one-third show features of fluent dysphasia.10 Cranial MRI imaging is usually indicated in the investigation of onset dysarthria and dysphasia, and the context in which these symptoms are occurring, for example, a stroke or cerebral vascular accident type presentation or post-traumatic injury, influences the optimum direction of imaging and is out of the scope of this article.

Table 2

Examples of acute neurological conditions associated with aphasia/dysphasia

As speech and language returns, dysphasic elements become apparent; telegrammatic speech in which elements of grammar are omitted, anomia which is a word-finding difficulty, phonemic paraphasias where there is non-fluent sound substitutions, logorrhoea or absence of speech flow, semantic jargon or verbal incoherence and neologistic jargon where there is scrambled sound structures resulting in non-words. There may be an abnormal speaking rate and longer term; there may be impairment of language comprehension with problems with narrative, particularly the ability to make inferences. In the long term, there may be continuing reduced syntax abilities and word-finding difficulties with a reduced speaking rate and unusual articulatory speed. Pragmatic impairments, that is to say how the language is used in conversation and functional context along with problems with making inferences can persist, and there will be written language difficulties. The dysphasia in ‘occult’ and paroxysmal aetiologies, including temporal lobe neoplasms and Landau–Kleffner dysphasia, may be more challenging to recognise. Aphasia is rare in children, but needs to be considered in ‘odd’ presentations of fluctuating behaviour and communication as these conditions are devastating, but potentially treatable. Due to the potentially devastating impact of the acute neurological conditions that underpin aphasia/dysphasia and the potential benefits of timely treatment, for example, acyclovir in herpes encephalitis, the acute management of occlusive vascular disease and steroid treatment in Landau–Kleffner dysphasia, the general paediatrician should always refer children as soon as possible to paediatric neurology. Figure 2A shows encephalitic changes in the left temporoparietal region and figure 2B shows the postinfective changes.

Figure 2

(A) Acute changes in the left parietal temporal region in keeping with encephalitic process with acute changes of cortical thickening, high signal on T2-weighted imaging and restricted diffusion on diffusion-weighted imaging. (B) Postinfectious findings showing thin cortex and prominent gyral pattern on the left side in the left parietal temporal region and thalamus with residual thinning of the cortex and prominence of the sulci in relation to the right hemisphere. This observation is consistent with postinflammatory loss of brain matter.

Classical perisylvian areas involved in recovery in non-fluent dysphasia are the anterior language areas of the inferior frontal gyrus and adjacent insular cortex and the posterior language areas including the superior temporal gyrus and the inferior parietal lobe. Functional brain imaging studies confirm that recovery from aphasia is protracted, but ‘dynamic’. The respective roles of the impaired left hemisphere and the greater right hemisphere lateralisation change over time. While right hemisphere lateralisation follows the acquired brain damage in children with cerebral vascular accident and aphasia, greater subsequent recovery is seen in those where there is some degree of reorganisation in the left hemisphere.11 Proficiency in linguistic tasks and a better prognosis is associated with increasing lateralisation to the left hemisphere in the anterior language regions. Despite significant recovery of aphasia, many individuals show persisting dysphasic features characterised by reduced naming and phonetic fluency in spoken and written language.11 ,12

Paroxysmal and fluctuating acquired aphasia

Herpes simplex encephalitis, in which approximately half the children have primary Herpes Simplex Virus-1 (HSV-1) infection and in half it is a reactivation, presents the classical frontotemporal syndrome of fever and personality and behaviour changes. There may be fluctuating aphasia with or without hallucinations in a minority, and over 90% have non-specific features.8

Acquired epileptic syndromes associated with language regression/aphasia

Landau–Kleffner syndrome (LKS) is an epileptic aphasia occurring in childhood, which can start insidiously or appear as an auditory agnosia in a child who was previously either developmentally normal or had straightforward developmental delay in speech and language acquisition.13 It has a peak presentation of between 5 and 7 years with an age range of 3–10 years. The majority of children have a receptive aphasia, and this comes first and may be associated with unusual behaviour arising from the intense difficulty understanding language and verbal instructions. There is then a rapid and severe loss in spontaneous speech. While the electroencephalogram (EEG) shows prominent epileptiform activity, there may be no outward signs of seizures. In that sense, although it is a disorder of language associated with epilepsy, the actual epilepsy may be unrecognised. It is important to record the EEG in drowsiness and sleep as the abnormalities, which include classically sharp waves in the bitemporal areas and sometimes frontal dysrhythmias, may not be immediately evident in a routine EEG (figure 3).

Figure 3

EEG appearances in Landau–Kleffner dysphasia.

This acquired epileptic aphasia is one of the epileptic encephalopathies of childhood and is related to continuous spike wave discharges in non-rapid eye movement (REM) sleep.14 The diagnosis can be delayed as a child might appear deaf, or there may be behaviour disturbances and anxiety with the child being unable to understand what is happening and unable to relate his/her experience. Sometimes when LKS has been longstanding, there can be more of an autism spectrum disorder picture emerging, but in the early stages of LKS, there remains a desire to communicate and make social overtures. In contrast, the regression seen typically in the second year of life in autism spectrum disorder is associated with a clear regression in non-verbal communication and reciprocal social interaction. It is important to think of dysphasia arising from an epileptic encephalopathy because, although clinical epileptic seizures will ultimately occur in 70%–80% of children with LKS, they may not be very evident initially. One should always consider whether a child with a deteriorating picture of cognition and/or language with or without overt seizures could have one of these occult epileptic encephalopathic processes and seek advice from an epileptologist as it is important to conduct EEG under the correct conditions.15

Medical treatment may improve long-term prognosis, and although oral steroids appear to confer benefit, the optimum timing, dosage and duration remain unresolved.14

Intervention

When one considers how fundamental communication is for quality of life, it is surprising that dysarthria has attracted relatively little interest in the literature until recently. However, with the advent of neuroimaging techniques, such as fMRI and voxel morphometry and indications of progress from therapy interventions, this is changing.

Despite the importance of acquired dysarthria and dysphasia for disrupting quality of life, there is very little evidence on which to base treatment.16 However, Hidecker17 argues that intervention outcomes now have a potential framework and “could be measured with the World Health Organisation's International Classification of Functioning, Disability and Health (ICF) Framework; so body function level can be judged through perception eg loudness, as well as physiological changes and acoustic speech measurements such as fundamental frequency changes and speech intelligibility, at an activity level through conversational intelligibility and communication effectiveness and at a participation level through increased societal roles within and/or across life situations”.

Children with severe dysarthria and impaired motor skills pose particular challenges too when measuring receptive language levels to avoid misconstruing the child's abilities. However, tests of receptive vocabulary and language comprehension, in which responses can be adapted so that the child can indicate a choice out of pictures with no time constraints and limited motor function, are feasible for children with severe cerebral palsy of Gross Motor Function Classification System (GMFCS) IV and V.18

Brief intensive therapy is associated with gains in intelligibility and communicative interactions for some younger children with dysarthria and cerebral palsy.3 Although there is a paucity of evidence for the treatment options for children with acquired brain injury and dysarthria, there is some emerging evidence of improvement in speech function following traditional and biofeedback treatment for speech breathing.16 However, there is presently insufficient evidence to recommend intensity and duration of treatment.

Similarly, any neurophysiology required in the context of an onset epileptic dysphasia must be informed with the input from an epileptologist to ensure that the correct scope of monitoring including appropriate caucuses of sleep is included.

Augmentative and alternative communication (AAC) can have a role both in the acute management of dysphasia and dysarthria or should be considered when there is persistence of severe impairment of speech intelligibility or lack of speech. AAC includes unaided modes such as gesture and aided communication modes that can be low-technology systems such as photographs and pictograms or high-technology systems, which include voice output communication aids. People with a disability have a right to access a chosen form of communication, but there are a wide range of factors that influence how successful or not the introduction of an AAC device might be. The impact of high-technology AAC depends on a whole range of factors as diverse as the availability of technical support, reliability of the device, the sound of the voice output to the individual, family perceptions and knowledge and skill of the staff supporting the AAC user.19 Families may need to be reassured that AAC will not prevent the recovery of speech as they can worry that the child would become dependant on the system. As speech recovers, the child will always opt to employ it. It is vitally important to maintain communication, and it is a fundamental component of good quality of life following recovery from these devastating acquired dysarthric and dysphasic conditions.

The intervention and management of children with aphasia/dysphasia are principally the remit of the speech and language therapist within the multidisciplinary team. The types of aphasic difficulty, for example, word-finding anomia, will be supported by therapy strategies that cue the child into the desired word. High-level language difficulties can persist, affecting narrative and understanding of inference and metaphor. The speech and language therapist is therefore an important partner for the child and his/her family, wider peer group and other significant people, such as teachers, to explain how these types of language impairment can impact on the child's function and to create an understanding receiving environment. Dysphasic elements will also affect written language, and support and monitoring may be required in the long term, particularly given the breadth of the new technical vocabulary that the child is likely to encounter as he/she moves through his/her educational settings.

Summary

Acquired disorders of speech production in dysarthria and language in dysphasia are common sequelae of acquired brain injury. Dysarthria and dysphasia can also have an insidious onset in rare neurodegenerative conditions such as in Fazio–-Londe syndrome or be difficult to recognise due to their paroxysmal or behaviourally masked presentations such as in LKS. Flaccid dysarthria can be associated with risk to integrity of the airway and for these acquired speech disorders, there can be potentially rapid progression and yet increasing scope for effective treatment, making it imperative that these conditions are recognised. Historically, there has been quite restricted study on these conditions despite the devastation of acquired loss of communication, but this is now being addressed with advances in neuroimaging, neurophysiology and evidence-based interventions including that of AAC.

References

Footnotes

  • Competing interests None declared.

  • Provenance and peer review Commissioned; externally peer reviewed.

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