Abnormalities in sensibility accompanying central poststroke pain

ABNORMALITIES

IN SENSIBILITY ACCOMPANYING CENTRAL POSTJ. Boiviel, G. Leijonl and I. Johansson*, STROKE PAIN. DeptFi Neurol.1 and Radiol.2 Univ. Hospital, Linkoping, Sweden. Central post-stroke pain (CPSP)can Aim of investigati&. be caused by thalamic as well as extrathalamic cerebrovascular lesions(CVL), including CVL located in the pons and medulla. In a clinical study of 27 CPSP patients (pts), presented separately at this congress, it was found that besides pain, abnormalities in cutaneous sensibility was the only symptom common to all pts. In the present study these abnormalities were investioated usina clinical tests and auantitative methods. Patients and Methods. CT scans and'symptoms indicated thalamic CVL in 9 pts, extrathalamic supratentorial CVL in 6 pts, lower brainstem CVL in B pts and CVL of unidentified location in 4 pts. All CVL were infarctions, except 3 thalamic haematomas. Clinical testing included sensibility for touch, prinprick, cold, dermography, 2-PD and kinesthesia. In the quantitative tests thresholds for vibration, touch, blunt skin pinch, innoxious temperature, noxious heat and cold were examined. Results. All pts had decreased sensibility for either warmth/cold/heat/

cold pain, except two who like 12 other pts had hyperaesthesia for cold. The thresholds for touch were raised in 89% and 36%, resp., following thalamic and lower brainstem CVL, those for vibration in 77% and 14% of these pts. 89% had dysaesthesias, which were radiating in 46%. Dermography, 2-PD and kinesthesia was not affected in the pts with CVL in the pons and medulla. Conclusions. From the present material it appears that central poststroke pain always is accompanied by abnormalities in cutaneous sensibility, most severely affecting temperature and pain. These results could indicate that the crucial factor for the development of this pain is a lesion affecting the spinothal. tract or its relay or thalmocortical projections.

Analgesic mechanisms THE EFFECT

AFFERENT lian*

OF TRADITIONAL

ACUPUNCTURE

ANALGESIA

ON VARIOUS

FIBPES OF PERIPHERAL

NERVES. -Zhao Yan* & HOU ZonInstitute of Anesthesiology,

(SPON: O.Mayrhofer,

University

Vienna)

Institute of Physiology

m

& Acupuncture

Anesthesia Mechanisms, Xi'an Medical University, Xi'an, P.R. of China Aim of Inverstigation: The previous work in our laboratory demonstrated that the analgesic

effect brought

about by electro-acupuncture

is higher in

small fibres than in large fibres. In the present work, the role of small fibres

(groups III & IV) and large fibres

al acupuncture Methods:

analgesia

The experiments

of reflex digastric dental pulpis was inserted

were performed

electromyogram

regarded

on 40 rabbits.

as the index of pain response.

into the "Zusanli" point, then inserting

was observed

by applying novocaine

The amplitude

(ARDE) induced by stimulation

peated. The ARDE was recorded every minute. puncture

(groups I & II) in the tradition-

was analysed. of the

The filiform needle and pulling were re-

The analgesic

effect of acu-

before and after a selective block of small fibres on the peroneal

nerve or of large fibres by apply-

ing direct current. Results:

In the control

(ARDE 41.5%). After blocking gesia was lower

the traditional

analgesia

small fibres the effect of acupuncture

(ARDE 89%), but after blocking

effect was near control Conclusions:

series there was a clear acupuncture

anal-

large fibres the analgesic

(ARDE 54.8%).

The small afferent acupuncture

fibres play the principal

(manual needling)

analgesia.

role in