Rehabilitacija - Letnih. VII. 11111/ . -1 (2008) 
INVESTIGATING THE CENTRAL 
CONTROL OF RESPIRATION IN ALS - A 
PILOT fMRI STUDY 
B. Koritnik
1
, S. Azam
2
, C. M. Andrew2, J. Zidar
1
, S. C. R. Willams
2
, P. N. Leigh
2 
1 
In stitute of Clinical Neu rophysiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
2 
Deparment of Clinical Neu roscien ce, In stitute of Psych iatry, King's Co llege London , London, UK
BACKGROUND 
How the brain controls breathing is stili not completely 
understood ( 1 ). In recent years, functional magnetic resonance 
imaging (fMR1) has been used to study voluntary brealhing 
in healthy subjects (2). Respiratory failure due to progressive 
respiratory muscle weakness is lhe usual cause of death in 
ALS. Maximal sniff nasal pressure measurement was the 
single respiratory test combining linear decline, sensitivity in 
mild disease, and feasibility in advanced disease. Therefore it 
appears well suited to assess the decline of respiralory muscle 
strength, the risk of respiratory failure and to provide prognoslic 
information in ALS palients (3). Upper motor neuron abnor­
malities could add to the respiratory dysfunclion in ALS. 
HYPOTHESES 
We hypothesised thal fMRI during sniffing would reveal 
sniff ing-associated brain activation palterns both in healthy 
Compared to healthy subjects, ALS paticnts showed reduced 
activation bilaterally in lhe pref
r
ontal corlex, and to a lesser 
extent also in temporal and occipilal lobes and cerebellum. 
lncreased activation in ALS patients was found in left tem­
poral lobe only. 
CONCLUSIONS 
Using fMRI during sniffing, it is possible to visualise the 
cor tical sensorimotor network associated with voluntary 
control of breathing both in healthy subjecls and in ALS 
patients. The reduced prefrontal activation suggesls lhat 
a central neural component to the respiratory dysfunction 
could exisl in ALS. Some clinical observalions support 
this hypothesis (4). Reduced pref
r
ontal activation was also 
described in ALS patients using fMRI during hand move­
ments (5). 
subjecls and in ALS patients, and that ALS patients would show 
References : 
reduced cortical activation compared to healthy subjects. 
METHODS 
Six ALS patients and five healthy subjects were stud ied. Static 
inspiratory and expiratory mouth pressure and maximal sniff 
nasal pressure were measured. lmaging was performed on a 
3T Siemens Trio scanner. In each subject, 221 functional seans 
were acquired. Nasal pressure and chest movements were 
rneasured during scanning. An event-related experimental 
design was used. A submaximal sniff manocuvre was per ­
formed every 20 s. Image pre-processing and stalistical analy­
sis werc done using the SPM5 software. A random effects 
group analysis was performed (p < O.OJ uncorrected). 
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RESULTS 
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was found to be activated during sniffing in both groups. 
rli