Introduction - what is agnosia?

Agnosia is a neurological disorder that affects the processing of sensory information from the environment. It is characterised by disturbances in recognition or identification abilities, which usually manifests as a limited loss of function.¹  Several different types of agnosia exist, each affecting different elements of sensory processing. For example, visual agnosia is one general class of agnosia that affects sight. However, it can branch into more specific types, such as geometric-optic agnosia (the inability to interpret the orientation of different geometric shapes).¹ Another general type of agnosia includes acoustic/auditory agnosia, which can cause individuals to incorrectly use or place words within a sentence.¹ Tactile agnosia can cause deficits in recognising the qualities of objects, such as their size, shape or weight, when they are presented in a tactile manner (e.g. when a patient is blindfolded and handed an object).²

If left untreated, agnosia can negatively impact a child's social and educational development. Luckily, by identifying the issues early, the child can build up a support system and develop strategies to manage any perceptual difficulties they may experience.

Types of agnosia in children

Visual agnosia

Visual agnosia is the inability to recognise objects without having any vision-related or intelligence problems. Apperceptive agnosia refers to disturbances in the visual perception of an object. For example, if an individual with visual agnosia is asked to copy a drawing of an object, they will likely be unable to do it correctly. In 2003, Eriksson et al.. showed an example of this when their 8-year old patient was able to perceive the individual details of a picture but could not recognise its overall meaning.³

Auditory agnosia

Auditory agnosia refers to a general impairment in the recognition of sounds (including environmental and speech-related sounds and music).⁴ One patient in a study published by Kaga et al. - a 7-year-old boy - was able to talk fluently, but his articulation was impaired. He was able to respond to quiet human voices or subtle environmental sounds, but it seemed as if he was unable to understand what was being said to him.⁵

Tactile agnosia

Tactile agnosia refers to the impaired ability to recognise objects through palpation (touching). These impairments can manifest in three ways: 1) issues with receiving sensory data of the object, 2) the sensory data not matching any stored data or memories about the object, and 3) the failure to recognise is due to a deeper level of systemisation.⁶ There are not many case studies that show tactile agnosia in children. However, children can still be affected. 

Other forms of agnosia

Prosopagnosia is the inability to recognise familiar faces.³ Individuals with prosopagnosia can recognise that a face is a face, rather than a car or a rock, but they are unable to recognise it if it is familiar to them or whose face it is. Other identifying features are often relied upon, such as voice, but if something changes, like a hairstyle, the patient may have trouble identifying the person.⁷

Causes of agnosia

Neurological basis of agnosia

Several regions of the brain can be involved in agnosia, including the occipital lobes and the temporal lobes. However, agnosia can also be linked to widespread damage.² Lesions in the brain formed after strokes, head injuries, or other brain damage can spread throughout the brain and cause agnosia.² 

Specific regions of the brain, if damaged or malformed, have been linked to specific types of agnosia. For example, damage to the ventral visual areas is associated with prosopagnosia.²

Genetic and developmental factors

Genetics may be involved in the development of agnosia. A 1999 study by Bentin et al. showed how a parent’s face recognition problems could have resulted in the development of prosopagnosia in their child.⁸ There are other conditions that may co-occur with agnosia. Indeed, in children, visual agnosia is associated with symptoms such as autism and/or mental retardation.³ 

Identifying agnosia in children

Early signs and symptoms 

Symptoms of agnosia can be visible very early in a child’s life. Issues during pregnancy or infancy can lead to perceptual difficulties. For example, Eriksson et al. noted how A.V., an 8-year-old boy with major visual perception deficits, experienced only minor medical difficulties in infancy but was later diagnosed with learning difficulties after psychological examinations.

Diagnostic tools and techniques

Diagnostic testing is used to identify any problems that patients may have. In the case of A.V., testing was prompted by the return of his medical issues from infancy. These psychological exams showed learning disabilities. The exams involved the use of neuroimaging tools such as sleep EEG tests, which suggested that A.V. had visual agnosia caused by issues in the occipitotemporal regions of the brain.³ In further neuropsychological tests, A.V. was unable to identify pictures when tested, and if he was able to recognise objects, he responded slowly. Furthermore, a copying test called the Developmental Neuropsychological Assessment (NEPSY) was used (as shown in the picture below).³

The top half of the image showed the pictures A.V. was asked to copy; the bottom row shows his attempts. As illustrated, his performance was poor, and his line orientation was impaired. Other tests were used to measure A.V.’s perceptual difficulties. In the Hooper Visual Organization Test, the average score for A.V.’s age was around 20 out of 30 objects; A.V. was only able to identify 8. His auditory attention was present, and his tactile skills were intact, which suggested the presence of only visual agnosia.³ This case illustrates the importance of testing for multiple types of agnosia at once, as it 1) ensures that the right diagnosis is reached and 2) allows for a more tailored approach to managing an individual’s condition. 

Role of parents and educators in early detection

A.V.’s difficulties were only reported because a teacher believed that there were some issues with his vision. When referred to an eye doctor, nothing was found, but after psychological testing, a diagnosis of agnosia was reached.³ This shows the importance of parents and educators in the diagnostic process, as they are usually the first ones to detect any difficulties children are facing. 

Management and intervention strategies

Tailored educational approaches

Accommodations for education are made during the process of diagnosis and also after treatment begins. As shown in Eriksson et al. (2003), A.V., at the age of 9, was moved from a mainstream school into a special school because of his learning disabilities. This is important since it can help the child to be more supported in school and also have an individualised plan for his education. Since A.V. only had visual agnosia, teaching techniques to be utilised can include auditory and tactile strategies.³

Therapeutic interventions

Upon publishing their study in 2005, Kaga et al.. recommended that patients with auditory agnosia undergo energetic speech therapy, which aims to make speech therapy more engaging through the use of fun exercises.⁵ However, compensatory strategies have also been suggested for the treatment of deficits associated with agnosia. For example, patients with visual agnosia can be taught to use cues to interpret visual stimuli, with a teacher explaining images to them.⁹ 

Patients may need to see multiple specialists both during and after their diagnosis. In the case of auditory agnosia, psychologists and speech pathologists may work together to make a treatment plan.⁵

Family support and counseling

Educating patients’ families about agnosia and the strategies best suited to support their child’s development can provide them with emotional and psychological support whilst also benefitting the child’s care. This can be valuable both at the point of diagnosis and for future monitoring. Further assessments to measure a child’s progress can be very useful in evaluating the success of the interventions being used and indicating where adjustments need to be made.

Challenges and considerations

The symptoms of agnosia vary significantly between patients, as well as the response to treatment and/or management strategies. Consequently, when a child undergoes testing for visual agnosia, they would need to have undergo specific testing for other forms of agnosia (e.g. auditory or tactile agnosia). Even after a general diagnosis is reached, further testing may be needed to specify the type of agnosia (for example, colour agnosia as a sub-class of visual agnosia).10 As such, treatment strategies must be made on an individual basis and only after comprehensive testing.

Summary

The early identification of agnosia in children is vital for the effective management and treatment of perceptual difficulties. There are many types of agnosia, and individualised treatment plans are usually needed. Diagnostic tools and techniques used to diagnose the different types of agnosia include neuroimaging, intelligence testing and specific tests such as the Developmental Neuropsychological Assessment.³ The range of tests used to diagnose agnosia shows the importance of identifying the type of agnosia, as managing the different types of agnosia requires different support and management strategies. In the case of A.V., auditory and tactile cues could be used to compensate for visual agnosia. 

Monitoring a child’s progress and the efficacy of the interventions being used can help to support a child’s growth. Over time, the establishment of support systems can help improve children’s social and educational development, as well as their mental health.