Monday, 23 May 2011

The nose knows

I always consider it a bit of bonus when PubMed lists a paper which is a bit out of left-field. Not that I am complaining when more "mainstream" science is also published. But every now and again something crops up leading to one of those 'mmm?' moments. The paper in question this time relates to the curious title of this post (which incidentally was a book I remember reading as a child, one of the few, I might add, myself not being a great reader of books in general): odor detection threshold, but not odor identification, is impaired in children with autism.

Why was I so drawn to this paper? Well, I can't say for sure. Maybe it was the connection to perception and the human senses, some of which I have blogged about previously in relation to autism (vision and hearing). Maybe it was the use of the unusual 'Sniffin Sticks' test. Maybe it was the focus on one of the more under-represented senses. I can't say.

The study and findings: a small-ish sized group with Asperger syndrome/high-functioning autism compared with age and gender matched non-AS controls.  The odor/odour detection threshold (the point at which a smell is smelled) using the Sniffin' Sticks method was different (higher) in the AS compared to control groups. The AS group were also better at smelling orange but worse at smelling cloves (no other significant differences in other smells were found). The same group have published in this area before and the other research in this area is equivocal.

Assuming that there is a biological explanation for the results, I do wonder if this might be a small part of the proposed social side of things relevant to autism. More and more the research seems to imply that the traditionally held beliefs on problems with social cues in autism for example are not being borne out by the research. Even eye movements in relation to attention in autism appear fairly typical.

Smell on the other hand is our hidden social moderator. Aside from providing us with quite a bit of information about the person or place or other thing we are presented with, smell is also tied into things like pheromones. I know that there is still some debate on 'the human sex scent' and whether we are so swayed by it. One however only needs to look at menstrual synchrony to see that there may still be something in it, even at a subconscious level.

One could also assume that issues with smell might also tie into problems with feeding behaviours given that the olfactory and gustational (taste) senses are inter-linked (as we all find out when we eat whilst having a cold). I do perhaps think it might be a step too far to say that the feeding problems described in autism are exclusively tied into a problem with smell, but you never know, it might be at least contributory.

I would be interested to see what other research comes out in this area in future.