Sensory perception testing by monofilaments in the digits of controls and workers with havs

Methods

Study population

Sensory perception was determined on the pulps of all the 

digits of both hands in three study populations: (1) office 

workers; (2) heavy manual workers not exposed to HTV 

and (3) workers with HAVS. The office workers were all 

employees of the HSE, who spent most of their time using 

computers, were tested by the same investigator. Any office 

worker who undertook heavy manual work, played competi-

tive sport with their hands, or had a medical problem that 

could affect sensory perception in the hands, such as carpal 

tunnel syndrome, was excluded from the study. All subjects 

were tested whilst comfortably seated in a quiet room.

The heavy manual workers were bricklayers, roofers and 

scaffolders who were working on large commercial build-

ing sites in the UK. Those who had regularly used vibrat-

ing tools, such as labourers, were excluded. They were all 

tested by the same investigator. The population with HAVS 

was made up of workers who were judged by the referring 

occupational physician to have been exposed to enough HTV 

to get HAVS. They had been referred to the HSE’s Science 

and Research Centre, Buxton, UK for high level (Tier 5) 

HAVS health surveillance with quantitative sensory tests 

of the digits. All of them were examined by CJMP and as 

appropriate confirmed to have neurological HAVS. They 

were then staged according to the International Consensus 

Criteria (ICC) (Poole et al. 

2019

), which unlike the Stock-

holm Workshop Scale, is prescriptive in how sensory per-

ception loss should be determined. No cases of neurological 

HAVS were excluded during the collection period unless 

they were associated with median or ulnar nerve neuropathy.

There were no available data to indicate the likely size of 

the difference in SWM thresholds between the three study 

populations. A large sample of office workers was recruited 

to define demographic parameters such as age and sex, 

however the size of the two smaller groups (heavy manual 

workers and HAVS cases) was determined by the numbers 

required to set limit values and the constraints of the budget.