Neurology -- Correspondence for Benson et al., 58 (1) 48-55

Correspondence published:

Older people with impaired mobility have specific loci of periventricular abnormality on MRI: Dennis Briley (5 April 2002)

Older people with impaired mobility have specific loci of periventricular abnormality on MRI 5 April 2002

Dennis Briley
Stoke Mandeville Hospital and Radcliffe Infirmary Oxford UK
Send Correspondence to journal:
Re: Older people with impaired mobility have specific loci of periventricular abnormality on MRI

dennis{at}dbriley.fsnet.co.uk Dennis Briley

I read the article by Benson et al. [1] with interest. My own data, based on CT imaging, support their conclusions. In a convenience sample of 343 patients, including patients with stroke, gait was examined with a standardized scale [2] and leukoaraiosis rated in seven brain regions using a modification of the van Swieten method [2, 3]. Neurologic abnormalities were quantified using the NIH stroke scale and supplemental scale. The brain region most correlated to gait disturbance was identified by analysis of variance. Ordered logit models were then used for further analysis (because of the ordinal nature of the gait scale).
The patients were predominantly male (96%) with a mean age of 68±10 years. Leukoaraiosis was found in 160 patients (47%). A history of stroke was present in 179 patients (52%), and radiologic evidence of stroke was present in 176 (51%). Leukoaraiosis correlated to the presence of subcortical stroke (64% versus 37%, p=0.001), but not to cortical stroke (47% vs 47%).
Analysis of variance found leukoaraiosis in the left frontal region had the highest correlation coefficient to the gait scale (r=0.49, p<0.0001; ordered logit coefficient 1.35, p<0.001). In the absence of left frontal leukoaraiosis, no other region showed statistical correlation to the gait scale (coefficients ranged from -0.13 to 0.19, p=ns). A history of stroke (coefficient 1.06, p<0.001 and radiologic evidence of stroke (particularly subcortical stroke: coefficient 0.73, p<0.001) both correlated to gait disturbance. Leg weakness or ataxia correlated to gait disturbance, but not to left frontal leukoaraiosis. In models including all of the above, only leg weakness and ataxia (coefficient 1.56, p<0.001) and left frontal leukoaraiosis (coefficient 1.32, p<0.001) were independent predictors of gait disturbance.
Thus, these data support the role of frontal white matter leukoaraiosis, particularly on the left side, as a necessary lesion in gait disturbance, but not more posterior leukoaraiosis. This may reflect either different methodology or the larger number of patients examined. Perhaps the specificity that Benson et al report with posterior leukoaraiosis reflects greater disease severity. While leukoaraiosis does appear to be a form of cerebrovascular disease [4], my data indicate the effects are independent of those of overt stroke. I agree that leukoaraiosis may be associated with a "significant portion of mobility impairment" in older individuals and that further natural history studies are necessary as this may portend a poor prognosis [5].
Acknowledgement: I acknowledge the help of Susan Sergent, PA-C in data collection and Stuart Thomas, PhD in data analysis and my patients of the Huntington VAMC, Huntington, WV.
References:
1) Benson RR, Guttmann CRG, Wei X et al. Older people with impaired mobility have specific loci of periventricular abnormality on MRI. Neurology 2002;58:48-55.
2) Briley DP, Wasay M, Sergent S, Thomas S. Cerebral white matter changes (Leukoaraiosis), Stroke and Gait Disturbance. JAGS 1997;45;1434 - 1438.
3) van Swieten JC, Hijdra A, Koudstaal PJ, van Gijn J. Grading white matter lesions on CT and MRI: a simple scale. J Neurol Neurosurg Psychiatry 1990;53:1080-1083.
4) Pantoni L, Garcia JH. Pathogenesis of leukoaraiosis. Stroke 1997;28:652-659.
5) Briley DP, Haroon S, Sergent SM, Thomas S. Does leukoaraiosis predict morbidity and mortality? Neurology 2000; 54:90-94.