The BSL Verbal Learning and Memory Test

The British Sign Language Verbal Learning and Memory Test (BSL-VLMT) is the first test of verbal learning and memory in British Sign Language. It adopts the format of the Hopkins Verbal Learning Test Revised (HVLT-R, Benedict, Schretlen, Gronninger, & Brandt, 1998) but uses novel BSL stimuli. Test items and instructions are wholly in BSL and there is no English language requirement. The test uses single nouns and is equally suited to deaf people who prefer signed supported English. Norms are available for older deaf adults aged 50-89 years (N= 224).

This test provides deeper investigation of verbal learning and verbal short term memory. Equally it can be used as a screening test to identify short term memory difficulties which may indicate dementia or neurological degeneration. It can also be a useful measure of how quickly a person is able to learn, organize and retain a lexical list.

 

Age group targets

The BSL-VLMT has been normed for older adults aged between 50-89. It is suitable for use with all age groups but norms are not available for younger groups.

 

Content of the test

Test content is designed to tap verbal learning and short term memory processes. The BSL-VLMT replicates the format of the HVLT-R and has three learning trials with immediate free recall of a 12 item list drawn from three semantic categories. This is followed by delayed free recall, after an interval period during which other tests are undertaken, and a final yes/no recognition trial made up of 12 target words and 12 distractor words, half of which are semantically related and half unrelated.

Responses are recorded on a written scoresheet by the test facilitator. Responses are video recorded so they can be checked again after testing for maximum accuracy.

Verbal learning and memory tasks are often used in assessments to identify memory impairments and dementia. Spoken language tests such as the HVLT-R cannot be translated into BSL without destroying the psychological integrity of the test. For example, items are organised into semantic categories, one of which is precious stones. This semantic category is problematic for a number of reasons. Signs for precious stones are typically fingerspelled or a generic sign for stones used in jewellery is used e.g. a sign indicating a small round object on the ring finger accompanied by mouthing of the equivalent English word (‘ruby’, ‘emerald’, ‘sapphire’, ‘opal’ and ‘pearl’). This dependence on English makes gemstones a poor category for testing BSL sign recall. For such reasons, we developed completely novel stimuli taking BSL as our starting point. We adopted the format of the HVLT-R with permission from the authors, to create the BSL-VLMT; however, our test is comprised of items that are appropriate for Deaf BSL users, which have been carefully selected on the basis of the BSL norms (Vinson, Cormier, Denmark, Schembri, & Vigliocco, 2008). We ensured that the BSL-VLMT took into account phonological structure, iconicity and gesturability, as well as minimizing regional and generational differences in the signs chosen for stimuli and instructions.

 

Test development and standardisation esp. re Deaf of deaf, deaf of hearing etc.

The BSL-VLMT was developed by a team of psychologists and sign linguists, led by a deaf psychologist and a hearing native signing psychologist.

 

The test was given to 224 deaf older adults aged between 50-89 at an annual holiday for older deaf signers. The sample comprised of 20 native signers and 204 non-native signers. A screening questionnaire was used to ensure participants had no neurological history, visual impairment, additional disability or substance abuse. Participants had not consumed alcohol within 8 hours and were not taking medication known to affect cognition. Participants were either born deaf or had become deaf before the age of 10.

 

Usability incl. administration procedure, scoring, time cost

The BSL-VLMT is user friendly and easy to use after short training. The BSL-VLMT takes approximately 25 minutes to complete, scoring is usually done live but we recommend that individuals administering the test check the video after testing to ensure they have scored the recall items correctly for greater accuracy.

 

The BSL-VLMT is being among assessments used at the cognitive disorders clinic at the  National Hospital for Neurology and Neurosurgery

 

Availability

This study provides normative data for a unique group older deaf signers, for clinical and research use, with the hope that the provision of norms will benefit the deaf community and clinicians working with deaf patients. More validation work needs to be done with deaf individuals with dementia before this test can be used for assessment purposes on a clinical basis. 

This test is not yet available to use for purposes other than within the cognitive disorders clinic, administration of the test is currently only being carried out by trained professionals in the DCAL team. We are currently piloting how it works when administered remotely with other service users outside of DCAL. Training is needed before administering the BSL-VLMT and only clinical professionals should use it for clinical assessment purposes.

 

Strengths and weaknesses

This is the first test of verbal learning and memory in BSL, it has been collected by a deaf led team and we now have normative data and are in the early stages of collecting clinical data. Further development using this test needs to be done, with the collection of more clinical data and further uses for the test. For example: the test is likely to have good validity when responses are interpreted from BSL to English due to its single noun format, however this needs to be confirmed by research.

 

An important translational outcome is that the format, methods and techniques used here are transferable to sign languages in other countries, although new test stimuli will be needed for each national sign language. This is a first step towards more equitable assessment and treatment for deaf users of sign language who present with memory and cognitive disorders.

One limitation of the BSL-VLMT is the existence of only one form, unlike the HVLT-R, which has six different forms designed to reduce practice-related error for patients undergoing serial testing. We were constrained by the fact that there is limited normed data on BSL signs from which to draw our stimuli.

Author

Summarized by Tanya Denmark, Joanna Atkinson-Hearn, Jane Marshall, and Bencie Woll (2013).

 

For more information regarding this test, please contact  Tanya Denmark at King's College London, UK.