Gill-Thwaites & Elliott Consultants Ltd

Accurate Assessment

To help ensure an accurate assessment of the individual with a PDOC, Gill-Thwaites & Elliott Consultants Ltd provides skilled and highly trained assessors. Their selection is based on their extensive experience, diverse range of skills, knowledge and availability, as well as their ability to determine and apply the appropriate assessment tools to meet each patient's specific needs.

Assessor Skills: The importance of an Experienced, Skilled Assessor

The Challenges Faced in the Assessment of PDOC

Giacino and Kalmar (1997) stated that Vegetative State (VS) is “one of the best known but least understood and most controversial neurological syndromes in medicine”. Several studies have revealed levels of misdiagnosis of the VS patient as high as 43% (Andrews et al 1996, Tresch et al 1991). It is evident from the literature, that detailed, standardised assessments by skilled assessors are required to optimise the accuracy of diagnosis, in order to provide the individual with the best possible opportunity to respond (Wade 1996).

Causes of Misdiagnosis

Given the rarity of this specialist group, there are very few assessors who have seen a sufficient number of these patients to gain a suitable level of experience and expertise. Therefore, many patients’ responses are overlooked or misinterpreted by assessors who lack experience and will interpret clinical features such as reflex responses as being meaningful, and may also miss potentially significant responses if they possess suboptimal observation skills (Gill-Thwaites 2006).

Childs et al (1993), Andrews et al (1976) and Godbolt et al (2012) consider that misdiagnosis is often due to the lack of extended observation of cognitive awareness by assessors who do not have the time to commit to providing a schedule of frequent assessments. They identified that extended assessment will help to more accurately discriminate between the VS and MCS patient and ensure that a correct and incontrovertible diagnosis of the patient can be reached.

Another factor contributing to misdiagnosis is the failure to systematically involve the family and the carers as active participants and observers of the patient’s behaviours. Wade (1996) acknowledged the value of the contributions made by the family and the carers, and defined the need to interview and formally document their observations of the patient’s behaviours over time. Freeman (1996) stated that the assessor is designated as the judge, who is not solely dependent on his or her own knowledge, but makes use of all the experience available thus allowing a correct verdict to be reached.

In the literature that reports on the rates of misdiagnosis, the assessors identifying the errors in the diagnosis have been experienced (Andrews et al 1996, Tresch et al 1991). In addition, each of the assessment tools recommended for use with the PDOC individual (Seel et al 2010, Royal College of Physicians 2013, 2020) has been based on the inter-rater reliability of trained assessors (Giacino et al 2004, Shiel et al 2000, Gill-Thwaites and Munday 1999). This illustrates the importance of not only selecting the correct standardised assessment tool, but also of ensuring that the assessor is experienced and adequately trained to implement the assessment, and to accurately interpret the behaviours exhibited by individuals with PDOC.

Providing Accurate Assessment

All of our consultants are in the elite group of SMART Masters, Expert SMART Assessors and Advanced SMART Assessors, demonstrating that they are highly trained, have extensive clinical experience (in some cases they have assessed in the region of 300 patients each), possess finely-tuned observation skills, teach the SMART course to other SMART assessors, and fully understand the principles of accurate assessment of the individual in a PDOC.

Gill-Thwaites & Elliott Consultants Ltd is also committed to providing specialised education programmes, which will help to ensure that professionals, carers and family members have the awareness and knowledge to recognise responses, and contribute positively to a thorough assessment of the patient.

Accredited SMART Assessors Standards of Practice

SMART Assessors are expected to meet the ‘Accredited SMART Assessors Standards of Practice’ (click here to view) in all aspects of their work in order to maintain a consistent, professional approach.

Assessment Tools We Use

The Royal College of Physicians’ guidelines (2020) recommend a select range of tools for use with PDOC, in order to help reduce diagnostic error and encourage some degree of consistency for recording longitudinal outcomes. SMART is our tool of preference due to its reported high level of clinical accuracy in diagnosis (Godbolt et al 2012); however, SMART is sometimes useful in clinical assessments to be used alongside the Wessex Head Injury Matrix (WHIM) or we can undertake assessments with any other PDOC tool as considered appropriate for the individual with a PDOC and your requirements.

The Sensory Modality Assessment and Rehabilitation Tool (SMART)

SMART (Gill-Thwaites and Munday 2004) is an an investigative assessment and intervention tool developed to detect awareness, and functional and communicative capacity in the VS and MCS patient, where there have been no consistent or reliable responses elicited and where the individual’s potential function has yet to be fully explored.

Research has shown that 43% of patients who were felt to be in VS were misdiagnosed and were found to be aware following assessment with SMART (Andrews et al 1996).

SMART provides an extended graded assessment of the individual’s level of sensory, motor and communicative responses to a structured and regulated sensory stimulation programme. SMART comprises a ten-session behavioural observation assessment followed by a multi-sensory assessment programme. The SMART assessment is conducted within a one to three-week period, resulting in a bespoke intervention and management plan.

The family, team and carers are fully involved and their observations are recorded, explored and monitored.

The five-point SMART hierarchical scale defines in which of the five sensory modalities (visual, auditory, tactile, olfactory and where appropriate, gustatory) the individual is able to demonstrate awareness. While there is a range of useful tools available for this patient group, SMART is the only tool designed to address all of the following key areas:

  • To identify potential awareness in the VS patient.
  • To optimise the individual’s arousal levels to elicit optimal responses.
  • To identify the widest possible range of communication and functional abilities in the MCS patient, through MCS– and MCS+ lower, mid and upper spectrum. thus ensuring that the identification of the individual’s behaviour and functional and communicative repertoire is fully explored and detection is not left to chance.
  • To optimise the individual’s progress in the future through a clear and logical intervention and management plan derived from an intensive assessment protocol.
When is SMART indicated?

When the individual with a PDOC:

  1. Has not been assessed previously by an expert PDOC assessor with a standardised assessment.
  2. Has not had a confirmed diagnosis, and further assessment is required to identify awareness and the extent of their functional and communicative ability.
  3. Has been identified as being in a VS or MCS following severe brain damage, and requires full assessment to provide objective evidence to contribute to an accurate clinical diagnosis.
  4. Is in a MCS and has an inconsistent motor function and/or method of communication, or where the pathways for potential motor function and/or communication have not been fully explored.
  5. Has potentially meaningful responses which have been observed by the MDT, carers and/or family but these responses have not yet been explored.
  6. Has been observed to respond differently according to the team, family and/or carers and these variable views regarding the individual’s level of awareness requires robust investigation and assessment.
  7. Has not had a recent assessment and the MDT or case manager require a new baseline of responses and recommendations for resource allocation and team goals.

SMART provides a highly sophisticated investigation and assessment, and probably the most definitive evaluation of the level of behavioural response for distinguishing patients in VS from those in MCS, which is the primary purpose for which it was designed. It can also offer useful clinical information on the individual’s strengths and weaknesses in terms of responsiveness, to inform and optimise intervention. SMART possesses a wider spectrum of sensory assessment techniques compared to other existing tools to ensure all responses are fully investigated. As it is a multi-modal assessment, SMART is especially useful for evaluating patients with sensory limitations, such as those with cortical blindness.

What can our assessment protocol offer you and the individual with a PDOC?
  1. Identification of the type, frequency and meaning of behaviours observed at rest.
  2. A comprehensive assessment of areas of strength across all of the sensory modalities.
  3. Comparison of the family and the carers’ observations with the results achieved in SMART.
  4. A suggested diagnosis based on analysis of the assessment.
  5. A graded and structured intervention and/or management plan incorporating all findings from the assessment and the family/team feedback.
  6. Identification of the resources, treatment and sensory programmes required to optimise the potential and quality of life of the individual with a PDOC.

A webinar is available to provide a detailed description of SMART – Click here to watch


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Childs, N.L., Mercer, W.N. and Childs, H.W. (1993) Accuracy of diagnosis of persistent vegetative state.

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Gill-Thwaites, H. (2006) Lotteries, loopholes and luck: misdiagnosis in the vegetative state patient.

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Morrissey A.M., Gill-Thwaites, H., Wilson, B., Leonard, R., McLellan, L., Pundole, A., & Shiel, A., (2017): The role of the SMART and WHIM in behavioural assessment of disorders of consciousness: clinical utility and scope for a symbiotic relationship.

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Shiel, A., Horn, S., Wilson, B.A., Watson, M.J., Campbell, M.J. and McLellan, D.L. (2000) The Wessex Head Injury Matrix (WHIM) Main Scale: a preliminary report on a scale to assess and monitor patient recovery after severe head injury.

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Tresch, D.D., Sims, F.H., Duthie, E.H., Goldstein, M.D. and Lane, P.S. (1991) Clinical characteristics of patients in the persistent vegetative state.

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