Brain (1997), 120, 785–794
Spatial and temporal auditory processing deficits
following right hemisphere infarction
A psychophysical study
T. D. Griffiths,1,2,4 A. Rees,1 C. Witton,1 P. M. Cross,3 R. A. Shakir5 and G. G. R. Green1
1Department of Physiological Sciences, the 2Department of Correspondence to: Dr T. D. Griffiths, Department of
Clinical Neuroscience, the 3Department of Clinical Physiological Sciences, Newcastle University Medical
Psychology, Newcastle University, Newcastle upon Tyne, School, Newcastle upon Tyne NE2 4HH, UK
the 4Wellcome Department of Cognitive Neurology, Institute
of Neurology and the 5Regional Neurosciences Centre,
Charing Cross Hospital, London, UK
Summary
Higher auditory function in a patient was investigated provides further evidence for the existence of amusia as a
distinct form of auditory agnosia, but does not support thefollowing a right hemisphere infarction between the middle
and posterior cerebral artery territories involving the hypothesis that bilateral lesions are required to produce such
a deficit. Unexpectedly, the patient was also found to have ainsula. The patient complained of lack of musical appreciation
and a battery of tests confirmed a dissociated receptive deficit in the perception of apparent sound-source movement.
We suggest that this deficit is analogous to the visualmusical deficit in the presence of normal appreciation of
environmental sounds and speech. The ability to detect phenomenon of akinetopsia, and is in accord with PET work
suggesting involvement of areas outside primary auditorycontinuous changes in sound frequency in the form of
sinusoidal frequency modulation was preserved. There was, cortex in sound movement perception. A possible common
deficit in auditory temporal and spatial ‘scene analysis’ ishowever, a deficit in the analysis of rapid temporal sequences
of notes which could underlie his musical deficit. This case discussed.
Keywords: amusia; right hemisphere; stroke; auditory psychophysics
Abbreviations: FM 5 frequency modulation; IAM 5 interaural amplitude modulation; IPM 5 interaural phase modulation
Introduction
The term ‘auditory agnosia’ was originally introduced by of spatial sound analysis and found a striking deficit in the
perception of acoustic properties used as cues for sound-Freud (1891) for a deficit in perception of certain complex
movement analysis. This deficit has been reported as asounds in the absence of deafness. Early descriptions focused
striking deficit in its own right (Griffiths et al., 1996).on the speech domain (Lichtheim, 1885) but later work has
focused on whether dissociated deficits in appreciation of
environmental sounds and music constitute distinct agnosias
(Spreen et al., 1965; Peretz et al., 1994). Auditory agnosia Case report
is rare, and the low incidence has been attributed to an H.V. and age-matched controls all gave informed consent to
‘almost constant’ association with bilateral cortical lesions participate in this study, which was approved by the Ethics
(Peretz et al., 1994). We describe here a case of dissociated Committee of Newcastle University. H.V. was assessed at
loss of musical perceptual ability following a unilateral the age of 75 years, 1 year after a watershed infarction between
right hemisphere lesion, which we have characterized the right middle and posterior cerebral artery territories. He
psychophysically as a deficit in rapid auditory sequencing. had presented with left-sided arm and leg weakness and a
Apart from investigating the deficit in the temporal analysis left homonomous hemianopia without depression of his
conscious level. He was an in-patient for a period of 2 weeks,of sound, we have also carried out psychophysical assessment
© Oxford University Press 1997

786 T. D. Griffiths et al.
during which time his left-sided weakness resolved. He was EEG recording showed the presence of right-sided temporal
slow wave activity.admitted again 3 months after the first admission after an
episode of collapse and obtundation. He was found to
have left visual and tactile hemi-inattention, and was also
Psychological assessment (Table 1)documented to be in atrial fibrillation.
Premorbid Global IQ was estimated to be 122 using theDuring the second admission the patient complained of
National Adult Reading Test. Assessment using the reviseddifficulties with the comprehension of music which he had
Wechsler Adult Intelligence Scale gave a Full Scale IQ offirst noticed after discharge following the initial event. He
117, with no significant discrepancy between performancehad a lifelong interest in music, having been a chorister as
and verbal subscales. H.V. showed significant impairment ina boy, though with no formal training in reading or playing
the block design and digit symbol subtests of the performancemusic. After his voice broke he continued to sing frequently
scale. The Visual Object and Space Perception Batteryin amateur light opera and shows. He had always taken
confirmed the presence of visiospatial deficits with failure inpleasure in listening to music, and particularly enjoyed
the dot counting and cube analysis subtests. The Westernpopular classical piano pieces. H.V. fulfils the criteria for
Aphasia Battery revealed no abnormality of speechGrison’s (Grison, 1972) third level of musical culture.
perception, but a right hemisphere language battery showedFollowing the first admission, he noticed that he could not
scores slightly below the mean for non brain-damagedrecognize some tunes that had previously been familiar to
subjects but above the mean for right brain-damaged subjects.him, such as theme tunes to television programmes he knew
well. In some cases he was able to use particular clues in
the tune to help him recognize it. The most effective cues
Agnosia assessment (Table 2)were slowly changing notes, such as the long sustained brass
note at the onset of the theme to the UK television programme Tune recognition
‘Coronation Street’. Additionally, he described a difficulty Twenty-four melodies were sung by a female singer in the
recognizing piano music with which he had previously been form ‘la, la, la’ using tunes that the patient and his wife
familiar. A particular feature was that music no longer knew by title. The patient was given up to two lines of the
brought him any enjoyment, and actually sounded unpleasant, song. The melodies included simple nursery rhymes such as
like ‘an out of tune child’s dulcima’. Listening to stereo ‘Three Blind Mice’, popular songs such as ‘Summertime’,
sound no longer produced any improvement in sound quality and well-known hymns such as ‘Jerusalem’. For each tune
and he was unable to distinguish stereo from mono music he was scored with 0 (failed to identify), 1 (incorrect but
on his music system. He also felt that his ability to sing close) or 2 (correct). The patient scored 24 out of 48 for
had been impaired. H.V. had reported no difficulty with this task.
recognizing lyrics or speech or environmental sounds. In
particular, he had not noticed any difficulty with appreciation
of spatial qualities of environmental sounds, though he has Lyric recognition
led a very sheltered lifestyle after the initial event. The deficit Single-line lyrics from 10 popular tunes, again selected on
had changed little between discharge after the first admission the basis of those his wife said he knew well, were read out
and his assessment. as prose and the patient asked to identify the tune by name.
Neurological assessment 1 year after his event revealed H.V. scored 20 out of 20 using the same scoring as tune
left visual inattention and slightly brisker left limb reflexes recognition.
without any weakness. He is right-handed for writing and
scores 11 out of 12 correct on an Annett hand preference
Environmental sound recognitionquestionaire (Annett, 1970).
Twenty exerpts from a BBC sound effect CD (BBC CD 792)
were played and the subject asked to identify the sound.
Common sounds with which the patient would have been
Lesion localization (Fig. 1) familiar were selected from the CD. These included the
Figure 1 shows MRI scans performed 4 months and 12 sounds of animals such as dogs and cows, mechanical noises
months after the initial event. The early scan shows diffuse such as trains and aeroplanes, and other environmental noises
mild atrophy with a region of altered T2 signal in the such as footsteps and church bells. H.V. scored 36 out of 40
right hemisphere, consistent with an infarction between the compared with a mean of 39 out of 40 in age-matched
right middle and posterior cerebral artery territories. The controls .
region of altered signal extends forward along the bank of
the right insula. The scan also shows several small discrete
areas of altered signal in the white matter of both hemispheres. Prosody
The late scan shows regional atrophy affecting the temporal The nonsense sentence ‘fi gait schong gil gosser’ was said
by a male speaker in a variety of manners with the patientlobe and altered signal in the right insula.