Preverbal Visual Assessment Paper

Paper: Development of the Preverbal Visual Assessment (PreViAs) Questionnaire, V Pueyo et al, link at end of page.

This paper explains the research process from a Spanish team to create a questionnaire seeking to identify visual difficulties in very young children, from just a few weeks old.

The questionnaire is called PreViAs, which is short for Preverbal Visual Assessment.


  • Because standard vision tests carried out on babies are not designed to pick up brain based visual impairments, with the exception of reduced visual acuity, and 'rarely' (according to the paper) visual field impairments.
  • Because the earlier any problems affecting learning and development are correctly recognised, the sooner interventions can start, the earlier the correct intervention, the better the outcome.

There is no doubt that a questionnaire of this nature is needed, especially as we now know from the CVI Project findings that at least, on average, one child in thirty is likely to have CVI, and as a result 80% of these will probably struggle with aspects of learning. But...

  • what exactly does it seek out?
  • how do you test very young children who have not yet learnt to talk, so can't follow instructions nor answer questions?
  • does it work?

The PreViAs team recognised that:

Visual difficulties in infancy may not only be due to poor visual acuity or visual field impairment, they may also be due to problems integrating visual information and their relationship to other cerebral functions

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In relation to cerebral visual functions, how do we know if a baby is developing typically?

The PreViAs team set out to see if they could identify accurate markers for visual difficulties in children of different ages, between new-born and two years of age, to determine typical development, and to pick up visual processing issues.

A questionnaire with twenty questions, was devised. For example:

  • Can the child look towards the source of a sound? And...
  • Does the child look at pictures in a story book?

The answers to these questions were organised into four categories:

  • Visual Attention
  • Visual Communication
  • Visual Motor Coordination
  • Visual Processing

These four categories are not intended to relate to specific cerebral visual impairments. Many of the questions relate to more than one of the four categories.

298 children between new-born and 2 years old (24 months) were assessed... but not by the doctors.

This team recognised that

Parents or other primary caregivers are the most appropriate individuals to determine whether a child has acquired certain abilities, as they spend the most awake time with their infant

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That might sound pretty normal, doctors always ask parents questions about their child, but this is a little different. Parents were given the questionnaire to take home and complete themselves, so essentially, the parents were assessing their own child.

Parents as Assessors - Pros & Cons

Let's look at the pros and cons of this, because it is an area, certainly from our team's experiences, where opinion seems to be divided...

  • Pros
  • The parent knows their child best, and the child is likely to best demonstrate their range of their abilities at home.
  • Children are often uncomfortable in clinical environments and may show fewer abilities than they actually have, which could lead to misdiagnosis.
  • The parent can observe the child in their own time, without the rush of an appointment slot.
  • Cons
  • Parents might exaggerate their child's abilities, or even not be entirely truthful if they are worried something may be wrong.
  • Parents might not understand the assessment, or may not have the reading and writing skills to conduct it.
  • Parents might not feel comfortable assessing their own child.
  • Parents might feel they are unqualified or that it is the job of the doctor.

CVI Scotland champions the rights of parents, so you would imagine we would unquestionably agree with parents assessing their child, but one of these issues does, we think, need considering:

  • Parents might not feel comfortable assessing their own child.

That is quite a responsibility and a lot of pressure to put on a parent - what if they get it wrong? If you have children, how would you feel if you were asked to assess them at home, and the results of your assessment would have an impact on future interventions?

The thing is, as parents, we do this all the time anyway, but informally. If all other babies of a similar age are holding up their head and yours is not, then it is likely you will ask the doctor to check everything is ok. But sometimes parents don't know what to look for. A baby not holding their head up is obvious, but a baby not returning a smile, or not reaching for familiar things is less obvious.

The questionnaire was designed in consultation with a group of parents to keep it simple. The questions are not emotionally subjective.

Weighing up all the pros and cons, for accuracy, maybe it might be easier just to do the assessment in a clinic, but there is a problem. These assessments take time, they require thought, observation and reflection. Hospital clinics have to support all the infants in their community, and very simply, there isn't time, and the child has to be awake and alert to be best assessed.

Parents must feel assured that anything they detect would be further investigated. The PreViAs questionnaire is not a CVI diagnostic tool. PreViAs is simply a questionnaire to identify the presence of possible brain based visual processing issues in very young children and infants.

PreViAs does not discriminate individual CVIs, and this is where following suspicion of an issue, a full diagnostic CVI assessment should be conducted by a medical doctor.

What this research gives us, is markers of what is normal or typical development around twenty different skills, broken down into blocks of two months, so for example what is typical for a baby between 0-2 month, 2-4 months etc, across all of the twenty questions. This is called a normative data range.

Each question has a score, and this way it is potentially possible to assess whether an infant is developing typically. If not developing typically, then the score gives an indication of levels of severity. What it does not do is indicate what is specifically causing the issues raised, again, this is where diagnostic assessment is required.

So, PreViAs is an assessment questionnaire based on observed behaviours aiming to identify developmental issues related to brain based visual issues in very young children.

The research results show a very high level of consistency, and so can be considered reliable. Remember, it was parents who completed the assessments. The reliability factor is based on all of the different questionnaires coming back and being independently statistically analysed, and the findings showed remarkably high reliability. So looking back at the issue some may have that parents might exaggerate or are not capable of conducting assessments....well... this study shows that parents are actually highly reliable when it comes to assessing their own children at home.

This study shows that parents are actually highly reliable when it comes to assessing their own children at home.This study shows that parents are actually highly reliable when it comes to assessing their own children at home.

Non-Verbal Children

There is a group of children who are non-verbal, who often have profound multiple disabilities, whom we think would benefit from a similar evaluation.

Growing evidence we are sharing, is showing that in special schools, between a quarter to over a half of the children attending may well have CVI. As with babies who can't follow instructions or answer questions, identifying and diagnosing this group is tricky.

The questions in the PreViAs questionnaire are designed for children under two, and so may not be relevant to a fourteen year old non-verbal profoundly disabled child, but a similar questionnaire is definitely needed for this group, for whom visual processing difficulties go unidentified and so unaccommodated in the vast majority of cases.

This study show that we need not be frightened of letting parents be involved in assessment processes, they are anyway of course - every time a doctor asks a parent a question about their child they are part of the assessment process. Parents need to be both involved and empowered when it comes to brain based visual difficulties. Although there is no medical cure or treatment, appropriate intervention reaps dividends.

We just want to say this again, because it is important, this paper shows that...

Parents or other primary caregivers are the most appropriate individuals to determine whether a young child has acquired certain abilities, as they spend the most awake time with the infant.Parents or other primary caregivers are the most appropriate individuals to determine whether a young child has acquired certain abilities, as they spend the most awake time with the infant.


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At CVI Scotland we are devoted to helping people understand cerebral visual impairments, and together working towards developing the understanding of this complex condition.